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Infant Respiratory Symptoms Associated with Indoor Heating Sources
Abstract
This study examined the effects of indoor heating sources on infant respiratory symptoms during the heating season of the first year of life. Mothers delivering babies between 1993 and 1996 at 12 hospitals in Connecticut and Virginia were enrolled. Daily symptom and heating source use information about their infant was obtained every 2 weeks during the first year of life. Heating sources included fireplace, wood stove, kerosene heater, and gas space heater use. Four health outcomes were analyzed by reporting period: days of wheeze, episodes of wheeze, days of cough, and episodes of cough. A large percentage of infants had at least one episode of cough (88%) and wheeze (33%) during the heating season of the first year of life. Wood stove, fireplace, kerosene heater, and gas space heater use was intermittent across the study period. In adjusted Poisson regression models controlling for important confounders, gas space heater use was associated with episodes and days of wheeze. Wood stove use was associated with total days of cough, and kerosene heater use was associated with episodes of cough. Fireplace use was not associated with any of the respiratory symptoms. Use of some heating sources appears related to respiratory symptoms in infants.
... Wheeze. The pooled RR for the risk of wheeze for exposed versus not exposed subjects to wood burning was 0.96 (95% CI 0.85, 1.09), based on 15 studies (Honicky et al., 1985;Dekker et al., 1991;Maier et al., 1997;Spengler et al., 1994;Van Miert et al., n.d.;Volkmer et al., 1995;Ware et al., 2014;Zhou et al., 2013;Noonan et al., 2012a;Browning, 1990;Belanger et al., 2003;Merchant et al., 2005;Noonan and Ward, 2007;Triche et al., 2002;Zacharasiewicz et al., 1999) (Fig. 4). Influence analysis omitting one study in turn did not change the overall result (data not shown). ...
... Cough. The pooled RR for the risk of cough for exposed versus not exposed to indoor emissions deriving from any wood-burning device was 1.02 (95% CI 0.91, 1.15), based on 10 studies (Honicky et al., 1985;Levesque et al., 2001;Van Miert et al., n.d.;Volkmer et al., 1995;Ware et al., 2014;Noonan et al., 2012a;Browning, 1990;Belanger et al., 2003;Merchant et al., 2005;Triche et al., 2002) (Fig. 5). Influence analysis omitting one study in turn did not change the overall result (data not shown). ...
... A limitation of the available evidence is that most of the included studies evaluating the association between indoor solid fuel exposure and respiratory outcomes had a cross-sectional design. Cohort studies reported mixed results: some of them found an increased risk of respiratory effects among children exposed to wood burning (Honicky et al., 1985;Baker et al., 2006;Pettigrew et al., 2004) or coal burning (Baker et al., 2006;Hertz-Picciotto et al., 2007;Zejda and Kowalska, 2003); some found inconsistent results (Triche et al., 2002;Butterfield et al., 1989); while other cohort studies saw a null or inverse association between indoor wood or coal burning exposure and respiratory outcomes (McConnell et al., 2002;Zhou et al., 2013;Belanger et al., 2003;Merchant et al., 2005;Tin Tin et al., 2016;Lai et al., 2017). ...
Epidemiological studies have shown a positive association between exposure to outdoor and indoor solid fuel combustion and adverse health effects.
We reviewed the epidemiological evidence from Europe, North America, Australia and New Zealand on the association between outdoor and indoor exposure to solid fuel combustion and respiratory outcomes in children.
We performed a systematic review and meta-analysis. Pooled relative risks (RRs) and 95% confidence intervals (CI) were calculated using random-effects models.
We identified 74 articles. Due to limited evidence on other exposures and outcomes, we performed meta-analyses on the association between indoor wood burning exposure and respiratory outcomes. The RR for the highest vs the lowest category of indoor wood exposure was 0.90 (95% CI 0.77–1.05) considering asthma as an outcome. The corresponding pooled RRs for lower respiratory infection (LRI) and upper respiratory infection (URI) were 1.11 (95% CI 0.88, 1.41) and 1.11 (95% CI 0.85, 1.44) respectively. No association was found between indoor wood burning exposure and risk of wheeze and cough.
Inconsistent and limited results were found considering the relationship between indoor wood burning exposure and other respiratory outcomes (rhinitis and hay fever, influenza) as well as indoor coal burning exposure and respiratory outcomes in children. Results from epidemiological studies that evaluated the relationship between the exposure to outdoor emissions derived from indoor combustion of solid fuels are too limited to allow firm conclusions.
We found no association between indoor wood burning exposure and risk of asthma. A slight, but not significant, increased risk of LRI and URI was identified, although the available evidence is limited. Epidemiological studies evaluating the relationship between indoor coal burning exposure and respiratory outcomes, as well as, studies considering exposure to outdoor solid fuels, are too limited to draw any firm conclusions.
... only four sites in Connecticut (CT)), which doesn't allow for accurate modeling at sites far away from the monitoring sites. On the other hand, data collected at many different spatial locations using passive sampling as part of environmental epidemiological studies, such as the Acid/Aerosol study (Triche et al. 2002), generally provide an aggregate measure of the pollutant concentration over relatively long time periods (1-2 weeks), resulting in spatially dense but temporally sparse data. Such data sources do not allow accurate estimation of pollutant concentrations at a fine temporal scale. ...
... In this paper, we extend the SCARR model and fit it to the same data sources using the complete set of observations to develop a space-time model to estimate the concentration of NO 2 at a fine spatial and temporal resolution over the state of Connecticut for 1994 and 1995. Specifically, estimates of NO 2 from the CMAQ model available in a grid-cell format with relatively large pixel sizes (12 × 12 km) are calibrated in space and time while also refining their spatial resolution using observations from two sources (Acid/Aerosol epidemiologic study data (Triche et al. 2002), and US Environmental Protection Agency monitoring data (US Environmental Protection Agency 2011) measured at different spatial and temporal resolutions. In this analysis, the SCARR model is extended in three ways: (a) the first step of the model is developed as a space-time model instead of a purely spatial model; (b) a parameter is included in the second step of the model that controls the influence of the estimated spatiotemporal calibration bias from the first step; and (c) additional covariates potentially correlated with atmospheric NO 2 are included. ...
... In the Acid/Aerosol study, 138 families were recruited from mothers delivering babies at seven Connecticut hospitals between 1993 and 1996 (Triche et al. 2002). Of these, 129 families had outdoor NO 2 concentrations measured at their residences by passive sampling using Palmes Tubes (Palmes et al. 1976). ...
A spatiotemporal calibration and resolution refinement model was fitted to calibrate nitrogen dioxide () concentration estimates from the Community Multiscale Air Quality (CMAQ) model, using two sources of observed data on that differed in their spatial and temporal resolutions. To refine the spatial resolution of the CMAQ model estimates, we leveraged information using additional local covariates including total traffic volume within 2 km, population density, elevation, and land use characteristics. Predictions from this model greatly improved the bias in the CMAQ estimates, as observed by the much lower mean squared error (MSE) at the monitor sites. The final model was used to predict the daily concentration of ambient over the entire state of Connecticut on a grid with pixels of size 300 300 m. A comparison of the prediction map with a similar map for the CMAQ estimates showed marked improvement in the spatial resolution. The effect of local covariates was evident in the finer spatial resolution map, where the contribution of traffic on major highways to ambient concentration stands out. An animation was also provided to show the change in the concentration of ambient over space and time for 1994 and 1995.
... only four sites in Connecticut (CT)), which doesn't allow for accurate modeling at sites far away from the monitoring sites. On the other hand, data collected at many different spatial locations using passive sampling as part of environmental epidimiologic studies, such as the Acid/Aerosol study (Triche et al. 2002), generally provide an aggregate measure of the pollutant concentration over relatively long time periods (1-2 weeks), resulting in spatially dense but temporally sparse data. Such data sources do not allow accurate estimation of pollutant concentrations at a fine temporal scale. ...
... In this paper, we extend the SCARR model and fit it to the same data sources using the complete set of observations to develop a space-time model to estimate the concentration of NO 2 at a fine spatial and temporal resolution over the state of Connecticut for 1994 and 1995. Specifically, estimates of NO 2 from the CMAQ model available in a grid-cell format with relatively large pixel sizes (12 x 12 km) are calibrated in space and time while also refining their spatial resolution using observations from two sources (Acid/Aerosol epidemiologic study data (Triche et al. 2002), and US Environmental Protection Agency monitoring data (US EPA, 2011)) measured at different spatial and temporal resolutions. In this analysis, the SCARR model is extended in three ways: (a) the first step of the model is developed as a space-time model instead of a purely spatial model; (b) a parameter is included in the second step of the model that controls the influence of the estimated spatiotemporal calibration bias from the first step; and (c) additional covariates potentially correlated with atmospheric NO 2 are included. ...
... Acid/Aerosol Study Data (Y 2 (s, [t s ])) In the Acid/Aerosol study, 138 families were recruited from mothers delivering babies at seven Connecticut hospitals between 1993 and 1996 (Triche et al. 2002). Of these, 129 families had outdoor NO 2 concentrations measured at their residences by passive sampling using Palmes Tubes (Palmes et al. 1976). ...
A spatiotemporal calibration and resolution refinement model was fitted to calibrate nitrogen dioxide (NO) concentration estimates from the Community Multiscale Air Quality (CMAQ) model, using two sources of observed data on NO that differed in their spatial and temporal resolutions. To refine the spatial resolution of the CMAQ model estimates, we leveraged information using additional local covariates including total traffic volume within 2 km, population density, elevation, and land use characteristics. Predictions from this model greatly improved the bias in the CMAQ estimates, as observed by the much lower mean squared error (MSE) at the NO monitor sites. The final model was used to predict the daily concentration of ambient NO over the entire state of Connecticut on a grid with pixels of size 300 x 300 m. A comparison of the prediction map with a similar map for the CMAQ estimates showed marked improvement in the spatial resolution. The effect of local covariates was evident in the finer spatial resolution map, where the contribution of traffic on major highways to ambient NO concentration stands out. An animation was also provided to show the change in the concentration of ambient NO over space and time for 1994 and 1995.
... Wheezing is often used as a surro-gate measure but is unreliable; in a Tucson, Arizona, cohort, by age 3 years, 19.9 percent of the children had at least one lower respiratory tract illness with wheeze but were no longer wheezing at age 6 years, 15.0 percent did not wheeze before age 3 years but did so at age 6 years, and 49.5 percent wheezed by age 6 years (33). Wheeze has been reported in the winter of the first year of life in 33 percent of infants (34) and to occur for 30 or more days in one third of infants who do wheeze (35). The difficulty in diagnosing childhood asthma has led to suggestions that the increase is in milder symptoms only and that some children may be treated inappropriately (29,36). ...
... Viral (251)(252)(253) and respiratory (44,254,255) infections before the age of 2 years have been associated with increased risk of asthma. Indoor heating sources (34,256), use of gas stoves (34,257,258), and nitrogen dioxide exposure (258)(259)(260)(261)(262)(263) have all been related to increased infant respiratory symptoms. ...
... Viral (251)(252)(253) and respiratory (44,254,255) infections before the age of 2 years have been associated with increased risk of asthma. Indoor heating sources (34,256), use of gas stoves (34,257,258), and nitrogen dioxide exposure (258)(259)(260)(261)(262)(263) have all been related to increased infant respiratory symptoms. ...
... In Connecticut and Virginia, Triche et al. [9] followed a cohort of children up to their first birthdays, noting episodes of coughing and wheezing. The authors linked the incidence of both symptoms to the type of fuel used for heating, finding a positive and significant relationship between the symptoms observed and gas heating, for example (RR 1.25; IC 95% 1.05-1.50). ...
... In the cohort study conducted in Connecticut by Triche et al. (2002) [9], mentioned above in the section on gas energy sources, the incidence of wheezing and cough was evaluated during the first year of life. The number of total days of coughing was correlated to the use of wood-burning stoves (OR = 1.10; ...
... In the cohort study conducted in Connecticut by Triche et al. (2002) [9], mentioned above in the section on gas energy sources, the incidence of wheezing and cough was evaluated during the first year of life. The number of total days of coughing was correlated to the use of wood-burning stoves (OR = 1.10; ...
We carried out bibliographic searches in PubMed and Embase.com for the period from 1996 to 2008 with the aim of reviewing the scientific literature on the relationship between various sources of indoor air pollution and the respiratory health of children under the age of five. Those studies that included adjusted correlation measurements for the most important confounding variables and which had an adequate population size were considered to be more relevant. The results concerning the relationship between gas energy sources and children's respiratory health were heterogeneous. Indoor air pollution from biomass combustion in the poorest countries was found to be an important risk factor for lower respiratory tract infections. Solvents involved in redecorating, DYI work, painting, and so forth, were found to be related to an increased risk for general respiratory problems. The distribution of papers depending on the pollution source showed a clear relationship with life-style and the level of development.
... Exposure to these harmful substances, due to a lack of ventilation, has been reported to increase the risk of various respiratory diseases [36][37][38][39]. For example, Sun et al. investigated the relationship between the amount of ventilation and sick building syndrome in Chinese homes [13]. ...
... Various pollutants such as CO, NO x , SO 2 , and VOCs are likely to be retained in houses with high CO 2 concentrations and insufficient ventilation, which may cause Sick Building Syndrome and respiratory diseases caused by long-term exposure [13,14,[36][37][38][39]. In addition, even when considering the effects of CO 2 alone, high concentrations have negative effects, such as reducing the ability to think, concentrate, and sleep [26][27][28]. ...
Indoor air quality (IAQ) in houses is often deteriorated by chemical substances emitted from heating, building materials, or other household goods. Since it is difficult for occupants to recognize air pollution, they rarely understand the actual conditions of the IAQ. An investigation into the actual condition of IAQ in houses was therefore conducted in this study. Carbon dioxide (CO2) concentrations in 24 occupied houses was measured, and the results from our analysis showed that the use of combustion heaters increased the concentration of CO2 and led to indoor air pollution. Results indicate that as outdoor temperature decreased, the frequency of ventilation decreased simultaneously, and CO2 concentration increased. Results of the questionnaire survey revealed that the actual IAQ in each house did not match the level of awareness its occupants had regarding ventilation. Along with this difficulty in perceiving air pollution, the lack of knowledge about ventilation systems and the effects of combustion heating may be additional barriers to IAQ awareness.
... A cohort study in Australia found that home gas appliance use was significantly associated with developing sensitisation to house dust mite and poor lung function tests (Ponsonby et al, 2001). Increased rates of wheezing in the first year of life of infants in homes using gas space heating has also been found (Triche et al, 2002). ...
... Inadequate building standards and unsafe buildings: injuries in the home; increased incidence of respiratory diseases, allergies, asthma (Licari et al, 2005;Breysse et al, 2004;Bonnefoy et al, 2004). Emissions of pollutants from using unflued gas for cooking and heating: respiratory disease, respiratory infections, increased susceptibility to asthma and changes in lung function (Bonnefoy et al, 2004Ponsonby et al, 2001Institute of Medicine, 2000;Triche et al, 2002). Tobacco smoke in the home: asthma, sudden infant death syndrome (SIDS), bronchitis, pneumonia and other respiratory diseases. ...
... A Connecticut study investigated the effects of acid aerosol exposure on respiratory symptoms in infants for which NO 2 levels were measured outside each subject's residence [19]. The primary source of outdoor NO 2 is thought to be vehicular engine exhaust, and thus related to ADT [20]. ...
... The primary source of outdoor NO 2 is thought to be vehicular engine exhaust, and thus related to ADT [20]. A full description of the health study methods is provided elsewhere [19,21]. Families were recruited from mothers delivering babies at seven Connecticut hospitals between 1993 and 1996. ...
Traffic exhaust is a source of air contaminants that have adverse health effects. Quantification of traffic as an exposure variable is complicated by aerosol dispersion related to variation in layout of roads, traffic density, meteorology, and topography. A statistical model is presented that uses Geographic Information Systems (GIS) technology to incorporate variables into a generalized linear model that estimates distribution of traffic-related pollution. Exposure from a source is expressed as an integral of a function proportional to average daily traffic and a nonparametric dispersion function, which takes the form of a step, polynomial, or spline model. The method may be applied using standard regression techniques for fitting generalized linear models. Modifiers of pollutant dispersion such as wind direction, meteorology, and landscape features can also be included. Two examples are given to illustrate the method. The first employs data from a study in which NO(2) (a known pollutant from automobile exhaust) was monitored outside of 138 Connecticut homes, providing a model for estimating NO(2) exposure. In the second example, estimated levels of nitrogen dioxide (NO(2)) from the model, as well as a separate spatial model, were used to analyze traffic-related health effects in a study of 761 infants.
... 12 Further, a US infant study reported that gas space heater use was associated with wheezing, wood stoves with cough, and kerosene heaters with cough. 13 Fragranced consumer products may be related to asthma or asthmatic symptoms among the general population, 14,15 although there has been a negative opinion. 16 A study among primary school children in China reported that the use of air fresheners reduced children's peak expiratory flow and small airway function, 17 and a Canadian study among 2-year children reported that air fresheners in the home were significantly associated with respiratory outcomes, including wheezing and coughing. ...
This prospective cohort study aimed to examine the associations between mold growth, type of stoves, and fragrance materials and early childhood wheezing and asthma, using data from the Japan Environment and Children's Study. Mold growth at home, usage of kerosene/gas stove, wood stove/fireplace, and air freshener/deodorizer were surveyed using a questionnaire at 1.5‐year‐old, and childhood wheezing and doctor‐diagnosed asthma during the previous year were obtained using a 3‐year‐old questionnaire. Multilevel logistic regression analysis was performed to evaluate the association between exposure to childhood wheezing and asthma. A total of 60 529 children were included in the analysis. In multivariate analyses, mold growth and wood stove/fireplace had significantly higher odds ratios (ORs) for wheezing (mold growth: 1.13; 95% CI, 1.06−1.22; wood stove/fireplace: 1.23; 95% CI, 1.03−1.46). All four exposures had no significant ORs for childhood doctor‐diagnosed asthma; however, in the supplemental analysis of northern regions, wood stove/fireplace had a significantly higher OR for asthma. Mold growth and wood stove/fireplace had significant associations with childhood wheezing in the northern regions. Mold elimination in the dwellings and use of clean heating (no air pollution emissions) should be taken into consideration to prevent and improve childhood wheezing and asthma.
... Household characteristics and individual activities both affect indoor air quality and thus, partially explain the disparity in respiratory disease among residents living in Navajo Nation. Household crowding, use of a household woodstove, poor indoor ventilation, and indoor tobacco smoke have been associated with higher risk of respiratory diseases [6,11,12]. In a 2013 Urban Institute Household survey, 15.9% of homes in tribal areas were overcrowded (defined by having more than one person per room) compared with 2.2% of U.S. households [13]. ...
Background
Indoor air pollution is associated with adverse health effects; however, few studies exist studying indoor air pollution on the Navajo Nation in the southwest U.S., a community with high rates of respiratory disease.
Methods
Indoor PM2.5 concentration was evaluated in 26 homes on the Navajo Nation using real-time PM2.5 monitors. Household risk factors and daily activities were evaluated with three metrics of indoor PM2.5: time-weighted average (TWA), 90th percentile of concentration, and daily minutes exceeding 100 μg/m³. A questionnaire and recall sheet were used to record baseline household characteristics and daily activities.
Results
The median TWA, 90th percentile, and daily minutes exceeding 100 μg/m³ were 7.9 μg/m³, 14.0 μg/m³, and 17 min, respectively. TWAs tended to be higher in autumn and in houses that used fuel the previous day. Other characteristics associated with elevated PM exposure in all metrics included overcrowded houses, nonmobile houses, and houses with current smokers, pets, and longer cooking time.
Conclusions
Some residents of the Navajo Nation have higher risk of exposure to indoor air pollution by Environmental Protection Agency (EPA) standards. Efforts to identify the causes and associations with adverse health effects are needed to ensure that exposure to risks and possible health impacts are mitigated.
... When comparing children whose parents did not use wood and coal, those who used wood and coal for heating indoors during humid weather conditions were 2.42 times more likely to develop respiratory symptoms. Evidence has shown that respiratory symptoms are a common problem with wood smoke exposure [27]. Studies suggest that wood smoke particles cause harm to human health through oxidative stress, cell toxicity, defects in cell regeneration, resulting in lung damage, and genotoxicity [28,29]. ...
Introduction:
Acute respiratory infections are still a major public health problem resulting in morbidity and mortality among under-five children. This study aims to assess the extent of respiratory symptoms and associated risk factors among under-five children in Gondar city, Northwest Ethiopia.
Methods:
A community-based cross-sectional study was carried out from February to June 2019. From 792 study participants, data were collected via face to face interviews by using a semi-structured pre-tested questionnaire. Data were entered in Epi Info version 7, then exported to Stata 14.00 for analysis. Binary (Bivariable and Multivariable) logistic regression analysis was used to test the association of explanatory and outcome variables. Variables with p<0.05 were considered as significantly associated with the outcome variable.
Results:
The prevalence of respiratory symptoms among under-five children was 37.5% at [95% (CI: 34.3-41)]. Uterine irritability during pregnancy [AOR = 1.89 at 95% CI: (1.11-3.23)], physical exercise during pregnancy [AOR = 0.60 at 95% CI: (0.41-0.89)], using wood and coal for heating [AOR = 2.42 at 95% CI: (1.65-3.53)], cockroaches infestation [AOR = 1.95 at 95% CI: (1.36 - 2.90)], presence of new carpets [AOR = 2.38 at 95% CI: (1.33-4.29)], damp stain [AOR = 2.45 at 95% CI: (1.02-2.69)], opening windows during cooking [AOR = 0.58 at 95% CI: (0.36-0 .93)], living less than 100 m heavy traffic [AOR = 1.94 at 95% CI: (1.16-3.27)], and living less than 100 m (unpaved roads/streets) [AOR= 2.89 at 95% CI: (1.89-4.55)] were significantly associated with respiratory symptoms.
Conclusion:
The prevalence of respiratory symptoms among under-five children was relatively high in the study area. Personal and environmental characteristics influencing symptom occurrence were identified. Respiratory symptoms will be minimized by reducing exposure to indoor and outdoor air pollution and enhancing housing quality.
... Household size, number of children under 5 years of age, child's playgrounds and maternal education level were not also found to be significantly associated with the prevalence of ARIs. However, several studies have shown that these socio-economic factors are related to the prevalence of ARI in children under the age of 05 [23,29,33,39,40,41]. ...
... La préparation des peaux d'animaux peut augmenter le taux de divers contaminants intérieurs, de même que les taux d'humidité. Les poêles à gaz et les poêles au kérosène s'associent à un risque plus élevé de toux et de respiration sifflante chez les nourrissons (54). ...
L’asthme est un grave problème de santé pour les enfants inuits et des Premières nations. Chez les enfants de moins d’un an, il faut distinguer l’asthme de la bronchiolite virale, anormalement fréquente chez les enfants autochtones du Canada. Chez les enfants de moins de six ans, le diagnostic dépend de la présence de symptômes classiques, de l’absence de caractéristiques atypiques et de la consignation de la réponse au traitement, notamment la réponse rapide et transitoire aux bronchodilatateurs. Chez les enfants plus âgés, il faut, dans la mesure du possible, déterminer la présence d’une obstruction réversible des voies aériennes par spirométrie afin de confirmer le diagnostic, ainsi qu’évaluer et corriger les déclencheurs environnementaux. L’utilisation régulière de corticoïdes en aérosol est la principale mesure à prendre pour maintenir un bon contrôle de l’asthme chez les enfants asthmatiques. Les clients et leur famille devraient recevoir une formation sur l’asthme. Il faut réévaluer régulièrement le contrôle aux visites de suivi dans des centres de santé et rajuster le traitement à la dose la plus basse possible pour le maintien de ce contrôle.
... Indoor sources of air pollution include gas and wood burning for heating and cooking which have been associated with respiratory symptoms and effects in children (Triche et al., 2002;Fuentes-Leonarte et al., 2009;Gillespie-Bennett et al., 2011). Contrary findings have also been reported (Bennett et al., 2010). ...
The environmental factors which may affect children’s respiratory health are complex, and the influence and significance of factors such as traffic, industry and presence of vegetation is still being determined. We undertook a cross-sectional study of 360 school children aged 5 to 12 years who lived on the outskirts of a heavy industrial area in Western Australia to investigate the effect of a range of environmental factors on respiratory health using the forced oscillation technique (FOT), a non-invasive method that allows for the assessment of the resistive and reactive properties of the respiratory system. Based on home address, proximity calculations were used to estimate children’s exposure to air pollution from traffic and industry and to characterise surrounding green space. Indoor factors were determined using a housing questionnaire. Of the outdoor measures, the length of major roads within a 50 m buffer was associated with increased airway resistance (Rrs8). There were no associations between distance to industry and FOT measures. For the indoor environment the presence of wood heating and gas heating in the first year of life was associated with better lung function. The significance of both indoor and outdoor sources of air pollution and effect modifiers such as green space and heating require further investigation.
... Historically, in air pollution epidemiology, most research has focused on characterizing the relationship between most severe asthma outcomes, such as hospital and emergency department (ED) visits, and air quality (Skoner, et al., 2002) (Roux, et al., 1999) (Abbey, et al., 1999) (Naeher, et al., 1999) (Triche, et al., 2002). But medication such as short-term beta-agonists may be a more sensitive marker for asthma than ED visits or hospital admission. ...
... Studies on gas heating often lacked information on whether the heater was directly vented to the outside, in which case it would not be a source of indoor air pollution. For this reason, we did not include gas heating [14][15][16][17][18][19] in the meta-analysis; indoor NO 2 and gas cooking were the exposure variables that we focused on. ...
Since the meta-analysis on the association between indoor nitrogen dioxide (NO2) and childhood respiratory illness in 1992, many new studies have been published. The quantitative effects of indoor NO2 on respiratory illness have not been estimated in a formal meta-analysis since then. We aimed to quantify the association of indoor NO2 and its main source (gas cooking) with childhood asthma and wheeze.
We extracted the association between indoor NO2 (and gas cooking) and childhood asthma and wheeze from population studies published up to 31 March 2013. Data were analysed by inverse-variance-weighted, random-effects meta-analysis. Sensitivity analyses were conducted for different strata. Publication bias and heterogeneity between studies were investigated.
A total of 41 studies met the inclusion criteria. The summary odds ratio from random effects meta-analysis for asthma and gas cooking exposure was 1.32 [95% confidential interval (CI) 1.18-1.48], and for a 15-ppb increase in NO2 it was 1.09 (95% CI 0.91-1.31). Indoor NO2 was associated with current wheeze (random effects OR 1.15; 95% CI 1.06-1.25). The estimates did not vary much with age or between regions. There was no evidence of publication bias.
This meta-analysis provides quantitative evidence that, in children, gas cooking increases the risk of asthma and indoor NO2 increases the risk of current wheeze.
... In relation to health outcomes, some articles in the literature have shown that the use of certain alternative fuels, the lack of heating or hot water, the existence of moisture and insufficient home ventilation are risk factors for respiratory health in household members (Dasgupta et al. 2004;Duflo et al. 2008). The medical literature in particular, remarks that the quality of the fuel and the kind of devices used to cook and provide heating inside the dwelling may affect the respiratory health of its inhabitants, especially that of children (Triche et al. 2002). In dwellings with building deficiencies and bad ventilation, the frequent use of fuel to cook in the same room that the household members use to sleep is a risk factor that increases the possibilities of suffering respiratory diseases (D'Souza 1997). ...
This study examines the programme Redes Solidarias, a public-private initiative that connected to natural pipelined gas 4,000 households in the Great Buenos Aires Area during 2005. The main features of the institutional framework are described and the main results of an impact estimation analysis are reported. The mechanism of selection of neighbourhoods for the connection represents a ‘natural experiment’, which allows the estimation of the causal effects of the programme on several indicators, including housing improvements, health and happiness related variables. We perform this analysis using data from two surveys we collected on the neighbourhoods in 2006 and 2007. The programme was found to generate improvements on dwelling walls, and the …
... In communities where wood-burning stoves are used, emissions may be associated with an increased risk of lower respiratory tract infection in Aboriginal children (19). Gas space heaters and kerosene heaters are associated with an increased risk of cough and wheeze in infants (20). ...
First Nations and Inuit Children are disproportionately affected by respiratory infections such as viral bronchiolitis, pneumonia and tuberculosis. Rates of long-term lung disease following severe respiratory infections early in life, such as bronchiectasis, are also elevated. In contrast, rates of asthma may be somewhat less than in other Canadian children, although rates of poor asthma control are increased. Causes for the high rates of infections include poverty, overcrowding, housing in need of major repairs and better ventilation, and increased exposure to environmental tobacco smoke. Improving these issues will require addressing the social origins of health in First Nations and Inuit communities, including poverty and employment, building more and improving existing housing, and will likely require developing enhanced immunization and surveillance strategies.
... The study of ancient Egyptian mummies with preserved internal organs (such as lungs) has shown cases of anthracosis that may have resulted from breathing indoor air polluted by open fires for cooking and heating. Nowadays, cooking and heating can affect respiratory illnesses in developed countries, albeit to a lesser degree than in developing countries, especially in children (Triche et al., 2002, Burr et al., 1999. Achieving levels of indoor air pollutants that are acceptable from a health point of view requires eliminating or controlling the sources of these compounds (Raw et al., 2004) and maintaining adequate ventilation in homes (Engvall et al., 2003). ...
The LARES Housing and Health survey conducted in representative samples of eight European towns provides substantial data from 3,373 households about housing conditions and the health of 8,519 residents. We assessed the relation between residential thermal comfort, weather-tightness, ventilation, mould or dampness and some common diseases and symptoms. We observed that reporting bad health was significantly associated with temperature, weather-tightness and mould or dampness problems. Asthma was significantly linked with mould or dampness, temperature, and ventilation problems. Hypertension and cold/throat illness were associated with temperature, mould or dampness, and weather tightness problems in the dwellings. These results make it possible to recommend improvements in existing dwellings, in particular of the weather tightness accompanied by better information and verification of the ventilation systems. These simple and not too costly actions might have a beneficial impact not only on comfort but on health too, as well as for energy savings.
... Curing animal hides may increase various indoor contaminants and indoor humidity levels. Gas space heaters and kerosene heaters are associated with a higher risk of cough and wheeze in infants (54). ...
Asthma is a serious health problem for First Nations and Inuit children. In
children younger than one year of age, asthma needs to be distinguished from
viral bronchiolitis, which is unusually common in Canadian Aboriginal children.
In children younger than six years of age, the diagnosis depends on the presence
of typical symptoms, the absence of atypical features and the documentation of
response to therapy - particularly a rapid, transient response to
bronchodilators. In older children, the presence of reversible airway
obstruction should be determined using spirometry whenever feasible to confirm
the diagnosis. Environmental triggers should be evaluated and corrected whenever
possible. Regular use of inhaled steroids is the most important measure for
maintaining good asthma control in children with asthma. Clients and their
families should receive asthma education. Control should be regularly reassessed
at follow-up visits in health centres, with therapy adjusted to the lowest level
capable of maintaining good control.
... A study of the association between winter respiratory symptoms and home heating sources was carried out in 890 infants, aged 3-5 mo, born in Connecticut and Virginia hospitals in (Triche et al. 2002. Mothers recorded wheeze and cough in their children. ...
Kerosene has been an important household fuel since the mid-19th century. In developed countries its use has greatly declined because of electrification. However, in developing countries, kerosene use for cooking and lighting remains widespread. This review focuses on household kerosene uses, mainly in developing countries, their associated emissions, and their hazards. Kerosene is often advocated as a cleaner alternative to solid fuels, biomass and coal, for cooking, and kerosene lamps are frequently used when electricity is unavailable. Globally, an estimated 500 million households still use fuels, particularly kerosene, for lighting. However, there are few studies, study designs and quality are varied, and results are inconsistent. Well-documented kerosene hazards are poisonings, fires, and explosions. Less investigated are exposures to and risks from kerosene's combustion products. Some kerosene-using devices emit substantial amounts of fine particulates, carbon monoxide (CO), nitric oxides (NO(x)), and sulfur dioxide (SO(2)). Studies of kerosene used for cooking or lighting provide some evidence that emissions may impair lung function and increase infectious illness (including tuberculosis), asthma, and cancer risks. However, there are few study designs, quality is varied, and results are inconsistent. Considering the widespread use in the developing world of kerosene, the scarcity of adequate epidemiologic investigations, the potential for harm, and the implications for national energy policies, researchers are strongly encouraged to consider collecting data on household kerosene uses in studies of health in developing countries. Given the potential risks of kerosene, policymakers may consider alternatives to kerosene subsidies, such as shifting support to cleaner technologies for lighting and cooking.
... As people nowadays spend most of time indoors, indoor air environment (IAE) is receiving increasing concern for its direct link with the health, comfort, and productivity of the occupants [1,2]. Compared to other industrial processes, indoor environment is of more complicated structure due to the discrete heat and contaminant sources, such as cooking, smoking, burning furnace, blazing window, o ce automation equipments, and building materials and furnishings, which intermittently or continuously produce heat, gas components (CO 2 ,CO,NO x ), particulate matter (PM 10 ; PM 2:5 ), and volatile organic compounds (VOCs) [3][4][5][6]. To control and/or remove these heat and contaminant so as to prevent them from doing harm to health, and also to provide thermal comfort, ventilation or air-conditioning is usually implemented as an indispensable measure. ...
A convection transport visualization technique is suggested to analyze the indoor air environment (IAE). A two-dimensional and laminar displacement ventilated room with discrete heat and contaminant sources is numerically investigated. Based on the governing equations, three convection transport functions, i.e. streamfunction, heatfunction, and massfunction, are derived to describe the fluid, heat, and contaminant transport processes, respectively. Main attentions are focused on the effects of the strength of heat source (Gr), the strength of contaminant source (Br), the strength of external ventilation (Re), and the positions of inlet/outlet openings on IAE. Numerical results illustrated that the abstract transport behaviors of the fluid, heat, and contaminant indoors are clearly exhibited by the convection transport functions which provides a simple but practical means of assessing IAE.
... 001 ). Indoor aerosol concentration is often higher than outdoor aerosol concentration and may potentially induce significant health effects, considering that people usually spend as much as 80–90% of their life indoors. For example, the PM levels indoors are very high when combustion processes, originating from cooking, heating or smoking , occur. Triche et al. (2002) studied the health effects (days and episodes of wheeze and cough) from indoor heating sources and revealed a significant association with respiratory symptoms. Similarly, Tan and Zhang (2003) concluded that indoor PM sources may be responsible for respiratory dysfunctions. Aerosols enter the human body mainly through the inhalation rou ...
Unlabelled:
Some indoor activities increase the number concentration of small particles and, hence, enhance the dose delivered to the lungs. The received particle dose indoors may exceed noticeably the dose from ambient air under routine in-house activities like cooking. In the present work, the internal dose by inhalation of ultrafine and fine particles is assessed, using an appropriate mechanistic model of lung deposition, accommodating aerosol, and inhalation dynamics. The analysis is based on size distribution measurements (10-350 nm) of indoor and outdoor aerosol number concentrations in a typical residence in Athens, Greece. Four different cases are examined, namely, a cooking event, a no activity period indoors and the equivalent time periods outdoors. When the cooking event (frying of bacon-eggs with a gas fire) occurred, the amount of deposited particles deep into the lung of an individual indoors exceeded by up to 10 times the amount received by an individual at the same time period outdoors. The fine particle deposition depends on the level of physical exertion and the hygroscopic properties of the inhaled aerosol. The dose is not found linearly dependant on the indoor/outdoor concentrations during the cooking event, whereas it is during the no activity period.
Practical implications:
The necessity for determining the dose in specific regions of the human lung, as well as the non-linear relationship between aerosol concentration and internal dose makes the application of dosimetry models important. Lung dose of fine and ultrafine particles, during a cooking event, is compared with the dose at no indoor activity and the dose received under outdoor exposure conditions. The dose is expressed in terms of number or surface of deposited particles. This permits to address the dosimetry of very small particles, which are released by many indoor sources but represent a slight fraction of the particulate matter mass. The enhancement of the internal dose resulting from fine and ultrafine particles generated during the cooking event vs. the dose when no indoor source is active is assessed. The results for those cases are also compared with the dose calculated for the measured aerosol outdoors.
... The acute and chronic health effects associated with woodsmoke from forest fire and residential wood burning are summarized in recent reviews by Naeher et al. [20] and Bølling et al. [21]. Epidemiology studies have revealed that young children are particularly susceptible to the effects of wood smoke with increased incidence of respiratory symptoms [22][23][24], asthma emergency department visits [25,26], and asthma symptoms [27,28]. Wood smoke has also been associated with increased cardiovascular emergency department visits [29]. ...
Wood burning for residential heating is prevalent in the Rocky Mountain regions of the United States. Studies have shown that wood stoves can be a significant source of PM
2.5
within homes. In this study, the effectiveness of an electrostatic filter portable air purifier was evaluated (1) in a home where a wood stove was the sole heat source and (2) in a home where a wood stove was used as a supplemental heat source. Particle count concentrations in six particle sizes and particle mass concentrations in two particle sizes were measured for ten 12-hour purifier on and ten purifier off trials in each home. Particle count concentrations were reduced by 61–85 percent. Similar reductions were observed in particle mass concentrations. These findings, although limited to one season, suggest that a portable air purifier may effectively reduce indoor particulate matter concentrations associated with wood combustion during home heating.
... A total of 3140 samples were available for use in model development: 508 (52%) contributed 4 samples, 262 (27%) contributed 3 and 22% contributed 2 (N ¼ 107) or 1 (N ¼ 108). Similarly collected NO 2 data from Connecticut residents participating in a study conducted in 1994 were used to validate the model and assess its accuracy (Beckett et al., 2006; Pettigrew et al., 2004; Triche et al., 2002 Triche et al., , 2005 Triche et al., , 2006). The 120 NO 2 samples used here for model validation were used previously for our earlier model development (Holford et al., 2010). ...
An integrated exposure model was developed that estimates nitrogen dioxide (NO(2)) concentration at residences using geographic information systems (GIS) and variables derived within residential buffers representing traffic volume and landscape characteristics including land use, population density and elevation. Multiple measurements of NO(2) taken outside of 985 residences in Connecticut were used to develop the model. A second set of 120 outdoor NO(2) measurements as well as cross-validation were used to validate the model. The model suggests that approximately 67% of the variation in NO(2) levels can be explained by: traffic and land use primarily within 2 km of a residence; population density; elevation; and time of year. Potential benefits of this model for health effects research include improved spatial estimations of traffic-related pollutant exposure and reduced need for extensive pollutant measurements. The model, which could be calibrated and applied in areas other than Connecticut, has importance as a tool for exposure estimation in epidemiological studies of traffic-related air pollution.
... Burning candles may be a source of particles in the indoor environment, but the health effects of such an exposure have not been fully elucidated. In some studies woodstoves have been associated with poor respiratory outcomes [14][15][16][17][18][19][20] . Two studies have shown that exposure to woodstoves was associated with decreased bronchial hyperresponsiveness, as well as lower prevalence of asthma, atopic sensitization and allergic rhinitis [21,22] , whereas others have not shown an association [23][24][25] . ...
Exposure to particulate matter (PM) outdoors can induce airway inflammation and exacerbation of asthma in adults. However, there is limited knowledge about the effects of exposure to indoor PM. The aim of this study was to investigate the association of exposure to indoor sources of PM with rhinitis symptoms, atopy and nitric oxide in exhaled air (FeNO) as a measure of airway inflammation.
We conducted a population-based cross-sectional study of 3,471 persons aged 18-69 years. Exposure to indoor sources of PM and prevalence of rhinitis symptoms were assessed by a self-administered questionnaire. Atopy was defined as at least 1 positive test (≥0.35 kU/l) for serum-specific IgE against grass, birch, cat or Dermatophagoides pteronyssinus. Regression analyses were used to adjust for confounders.
Self-reported exposure to the use of woodstoves, candles or gas kitchen cookers was not significantly associated with either increased prevalence of rhinitis symptoms or atopy or increased levels of FeNO. The prevalence of atopy and allergic rhinitis and the levels of FeNO were significantly decreased among current and previous smokers. Exposure to environmental tobacco smoke (ETS) for 0.5-5 h, but not above 5 h, was significantly associated with a slightly increased prevalence of rhinitis symptoms.
Self-reported exposure to the use of woodstoves, candles or gas cookers was not significantly associated with an increased risk of rhinitis symptoms or atopy, nor increased FeNO. Self-reported exposure to ETS was associated with a slightly higher prevalence of self-reported rhinitis symptoms without any clear dose-response relationship.
... Relatively few studies have been conducted in developed countries to directly assess the health impacts among children due to the more moderately elevated PM from residential woodstove usage. A prospective study of respiratory symptoms among infants observed an association between frequency of cough and woodstove use, but respiratory symptoms were not associated with fireplace use in the home (Triche et al., 2002). Cross-sectional observational studies indicated lung function decrement (Johnson et al., 1990) and higher frequency of symptoms that can be loosely described as asthma related (Butterfield et al., 1989; Honicky et al., 1985) among children living in woodstove homes compared to children living in homes without woodstoves. ...
Epidemiological studies of biomass smoke health effects have been conducted in a variety of settings and with a variety of study designs. The Health Effects Workgroup discussed several approaches for the investigation of health effects in communities exposed to wood smoke from nearby wildland fires, intentional agricultural burning, or residential biomass burning devices such as woodstoves or cookstoves. This presentation briefly reviews observational and intervention studies that have been conducted within these exposure settings. The review is followed by a summary of discussion points among the workgroup members with particular emphasis on study design and the use of biomarkers for assessing outcomes in biomass smoke-exposed populations.
... 18,19 Alternative heating sources that many poor families use can lead to adverse health consequences in young children, such as increased incidence of burns, 19 carbon monoxide exposure, and respiratory illnesses. 20,21 In 2002, 24% of all fatal home candle fires occurred in homes in which the power had been shut off, and children who were younger than 5 years faced the highest relative risk (RR) for death (2.5) from home candle fires of all age groups. 22 Despite the widespread need for LIHEAP, however, combined state and federal funding for the program enabled only 16% of eligible families to receive energy assistance in 2006. ...
Household energy security has not been measured empirically or related to child health and development but is an emerging concern for clinicians and researchers as energy costs increase. The objectives of this study were to develop a clinical indicator of household energy security and assess associations with food security, health, and developmental risk in children <36 months of age.
A cross-sectional study that used household survey and surveillance data was conducted. Caregivers were interviewed in emergency departments and primary care clinics form January 2001 through December 2006 on demographics, public assistance, food security, experience with heating/cooling and utilities, Parents Evaluation of Developmental Status, and child health. The household energy security indicator includes energy-secure, no energy problems; moderate energy insecurity, utility shutoff threatened in past year; and severe energy insecurity, heated with cooking stove, utility shutoff, or >or=1 day without heat/cooling in past year. The main outcome measures were household and child food security, child reported health status, Parents Evaluation of Developmental Status concerns, and hospitalizations.
Of 9721 children, 11% (n = 1043) and 23% (n = 2293) experienced moderate and severe energy insecurity, respectively. Versus children with energy security, children with moderate energy insecurity had greater odds of household food insecurity, child food insecurity, hospitalization since birth, and caregiver report of child fair/poor health, adjusted for research site and mother, child, and household characteristics. Children with severe energy insecurity had greater adjusted odds of household food insecurity, child food insecurity, caregivers reporting significant developmental concerns on the Parents Evaluation of Developmental Status scale, and report of child fair/poor health. No significant association was found between energy security and child weight for age or weight for length.
As household energy insecurity increases, infants and toddlers experienced increased odds of household and child food insecurity and of reported poor health, hospitalizations, and developmental risks.
... On the other hand, in the same study, woodstove but not fireplace use was associated with total days of cough in these infants (RR 1.08, CI 1.00,1.16) (Triche et al., 2002). In a panel study of adults (ages 18–70) in Denver, CO (Ostro et al., 1991), the use of a fireplace or woodstove was associated with an increase in daily moderate or severe shortness of breath(OR 1.3, CI 1.1, 1.4). ...
The sentiment that woodsmoke, being a natural substance, must be benign to humans is still sometimes heard. It is now well established, however, that wood-burning stoves and fireplaces as well as wildland and agricultural fires emit significant quantities of known health-damaging pollutants, including several carcinogenic compounds. Two of the principal gaseous pollutants in woodsmoke, CO and NOx, add to the atmospheric levels of these regulated gases emitted by other combustion sources. Health impacts of exposures to these gases and some of the other woodsmoke constituents (e.g., benzene) are well characterized in thousands of publications. As these gases are indistinguishable no matter where they come from, there is no urgent need to examine their particular health implications in woodsmoke. With this as the backdrop, this review approaches the issue of why woodsmoke may be a special case requiring separate health evaluation through two questions. The first question we address is whether woodsmoke should be regulated and/or managed separately, even though some of its separate constituents are already regulated in many jurisdictions. The second question we address is whether woodsmoke particles pose different levels of risk than other ambient particles of similar size. To address these two key questions, we examine several topics: the chemical and physical nature of woodsmoke; the exposures and epidemiology of smoke from wildland fires and agricultural burning, and related controlled human laboratory exposures to biomass smoke; the epidemiology of outdoor and indoor woodsmoke exposures from residential woodburning in developed countries; and the toxicology of woodsmoke, based on animal exposures and laboratory tests. In addition, a short summary of the exposures and health effects of biomass smoke in developing countries is provided as an additional line of evidence. In the concluding section, we return to the two key issues above to summarize (1) what is currently known about the health effects of inhaled woodsmoke at exposure levels experienced in developed countries, and (2) whether there exists sufficient reason to believe that woodsmoke particles are sufficiently different to warrant separate treatment from other regulated particles. In addition, we provide recommendations for additional woodsmoke research.
Use of wood for residential heating is regaining popularity in developed countries. Currently, over 11 million US homes are heated with a wood stove. Although wood stoves reduce heating costs, wood smoke may adversely impact child health through the emission of gaseous and particulate air pollutants. Our purpose is to raise awareness of this environmental health issue among pediatricians. To summarize the state of the science, we performed a narrative review of articles published in PubMed and Web of Science. We identified 36 studies in developed countries that reported associations of household wood stove use and/or community wood smoke exposure with pediatric health outcomes. Studies primarily investigated respiratory outcomes, with no evaluation of cardiometabolic or neurocognitive health. Studies found community wood smoke exposure to be consistently associated with adverse pediatric respiratory health. Household wood stove use was less consistently associated with respiratory outcomes. However, studies of household wood stoves always relied on participant self-report of wood stove use, while studies of community wood smoke generally assessed air pollution exposure directly and more precisely in larger study populations. In most studies, important potential confounders, such as markers of socioeconomic status, were unaccounted for and may have biased results. We conclude that studies with improved exposure assessment, that measure and account for confounding, and that consider non-respiratory outcomes are needed. While awaiting additional data, pediatricians can refer patients to precautionary measures recommended by the US Environmental Protection Agency (EPA) to mitigate exposure. These include replacing old appliances with EPA-certified stoves, properly maintaining the stove, and using only dry, well-seasoned wood. In addition, several studies have shown mechanical air filters to effectively reduce wood stove pollution exposure in affected homes and communities.
Each year, the general public and wildland firefighters in the US are exposed to smoke from wildland fires. As part of an effort to characterize health risks of breathing this smoke, a review of the literature was conducted using five major databases, including PubMed and MEDLINE Web of Knowledge, to identify smoke components that present the highest hazard potential, the mechanisms of toxicity, review epidemiological studies for health effects and identify the current gap in knowledge on the health impacts of wildland fire smoke exposure. Respiratory events measured in time series studies as incidences of disease-caused mortality, hospital admissions, emergency room visits and symptoms in asthma and chronic obstructive pulmonary disease patients are the health effects that are most commonly associated with community level exposure to wildland fire smoke. A few recent studies have also determined associations between acute wildland fire smoke exposure and cardiovascular health end-points. These cardiopulmonary effects were mostly observed in association with ambient air concentrations of fine particulate matter (PM2.5). However, research on the health effects of this mixture is currently limited. The health effects of acute exposures beyond susceptible populations and the effects of chronic exposures experienced by the wildland firefighter are largely unknown. Longitudinal studies of wildland firefighters during and/or after the firefighting career could help elucidate some of the unknown health impacts of cumulative exposure to wildland fire smoke, establish occupational exposure limits and help determine the types of exposure controls that may be applicable to the occupation.
Spatiotemporal calibration of output from deterministic models is an increasingly popular tool to more accurately and efficiently estimate the true distribution of spatial and temporal processes. Current calibration techniques have focused on a single source of data on observed measurements of the process of interest that are both temporally and spatially dense. Additionally, these methods often calibrate deterministic models available in grid-cell format with pixel sizes small enough that the centroid of the pixel closely approximates the measurement for other points within the pixel. We develop a modeling strategy that allows us to simultaneously incorporate information from two sources of data on observed measurements of the process (that differ in their spatial and temporal resolutions) to calibrate estimates from a deterministic model available on a regular grid. This method not only improves estimates of the pollutant at the grid centroids but also refines the spatial resolution of the grid data. The modeling strategy is illustrated by calibrating and spatially refining daily estimates of ambient nitrogen dioxide concentration over Connecticut for 1994 from the Community Multiscale Air Quality model (temporally dense grid-cell estimates on a large pixel size) using observations from an epidemiologic study (spatially dense and temporally sparse) and Environmental Protection Agency monitoring stations (temporally dense and spatially sparse). Copyright
Poor domestic air quality creates challenges for adults and children living with lung disease. This review will describe the role of household environmental triggers in the occurrence and exacerbation of respiratory illnesses such as asthma and chronic obstructive pulmonary disease. Major sources of air pollution in households include nitrogen dioxide, endotoxin, allergens, environmental tobacco smoke and volatile organic compounds. Remediation of the environment to prevent or reduce indoor exposures that can exacerbate lung disease and affect quality of life requires knowledge of the properties of indoor pollutants as well as an understanding of groups at risk for symptoms or disease. Gene-environment and environment-environment interactions with respiratory outcomes challenge the remediation process and require consideration when evaluating the effects of environmental interventions. Strategies must reflect the unique circumstances of the individual and the environment.
Energy insecurity may result in adverse consequences for children's health, particularly for children with special health needs or chronic health conditions. We aimed to determine whether a multimodal intervention addressing energy insecurity within the framework of a medical-legal partnership (MLP) resulted in an increase in the provision of certifications of medical need for utility coverage in an inner city academic primary care practice.
Working within a medical-legal partnership, we standardized criteria for providers approving medical need utility certification requests. We compared prior-year utility certification requests and approvals (pre-intervention) with the intervention year for families who reported energy insecurity on a waiting-room screening questionnaire.
Between the first and second years of the study, certification of medical need approvals increased by 65%, preventing utility shut-offs for 396 more families with vulnerable children.
Energy insecurity can be screened for and addressed in a busy urban practice, potentially improving the wellbeing of vulnerable children.
Background Kerosene is a widely used cooking and lighting fuel in developing countries. The potential respiratory health effects of cooking with kerosene relative to cooking with cleaner fuels such as liquefied petroleum gas (LPG) have not been well characterised.
Methods We sampled 600 households from six urban neighbourhoods in Bangalore, India. Each household's primary cook, usually the woman of the house, was interviewed to collect information on current domestic fuel use and whether there was any presence of respiratory symptoms or illness in her or in the children in the household. Our analysis was limited to 547 adult females (ages 18–85) and 845 children (ages 0–17) in households exclusively cooking with either kerosene or LPG. We investigated the associations between kerosene use and the likelihood of having respiratory symptoms or illness using multivariate logistic regression models.
Results Among adult women, cooking with kerosene was associated with cough (OR=1.88; 95% CI 1.19 to 2.99), bronchitis (OR=1.54; 95% CI 1.00 to 2.37), phlegm (OR=1.51; 95% CI 0.98 to 2.33) and chest illness (OR=1.61; 95% CI 1.02 to 2.53), relative to cooking with LPG in the multivariate models. Among children, living in a household cooking with kerosene was associated with bronchitis (OR=1.91; 95% CI 1.17 to 3.13), phlegm (OR=2.020; 95% CI 1.29 to 3.74) and chest illness (OR=1.70; 95% CI 0.99 to 2.90) after adjusting for other covariates. We also found associations between kerosene use and wheezing, difficulty breathing and asthma in adults and cough and wheezing in children, though these associations were not statistically significant.
Conclusions Women and children in households cooking with kerosene were more likely to have respiratory symptoms and illnesses compared with those in households cooking with LPG. Transitioning from kerosene to LPG for cooking may improve respiratory health among adult women and children in this population.
Background and objective: Mongolia is experiencing rapid urbanization, and this presents a unique opportunity to assess the effects of this process on the lung health of children.
Methods: Two cross-sectional cohorts of school-age children (5–15 years of age) from the capital (Ulaanbaatar) (n = 116) and a rural district (Tuv Aimag) (n = 108) were studied. Demographical information, exposure to tobacco smoke, and ambient and exhaled CO, as well as FEV1 and FEF25–75% were recorded for each child.
Results: Ambient CO levels were threefold higher in the capital city than in the rural Aimag (0.63 vs 0.21 parts per million (ppm), P < 0.00005), while exhaled CO was twofold higher (0.94 vs 0.47 ppm, P < 0.00001). Rural Mongolian children were 6 cm shorter on average than urban children. However, when adjusted for age and height, FEV1 was 140% of predicted in rural children compared with 106% of predicted in urban children (P < 0.00001). There was no significant difference in small airway expiratory flow (FEF25–75%; 104 in urban children, 100 in rural children, P = 0.63).
Conclusions: ‘Normal’ FEV1 was actually 40% higher in rural Mongolian children than in urban children, suggesting that the FEV1 of apparently healthy children living in urbanized societies may in fact not be normal, but may instead reflect the deleterious effects of air pollution in cities, as indicated by increased levels of both environmental and exhaled CO.
Exposure to particulate matter (PM) can induce airway inflammation and exacerbation of asthma. However, there is limited knowledge about the effects of exposure to indoor sources of PM. We investigated the associations between self-reported exposure to indoor sources of PM and lower airway symptoms and lung function.
A population-based cross-sectional study of 3471 persons aged 18-69 years was conducted. Information about exposure to indoor sources of PM and airway symptoms was obtained from a self-administered questionnaire.
Exposure to wood stoves, candles and gas cookers was not significantly associated with an increased prevalence of lower respiratory symptoms or decreased lung function. In contrast, persons exposed to environmental tobacco smoke for >5 h/day had a significantly increased risk of 'wheeze' (OR 1.69, 95% CI: 1.24-2.30) and 'chronic cough' (OR 1.57, 95% CI: 1.12-2.20), as well as decreased lung function (FEV(1)% predicted), compared with those who were not exposed. Similar trends were observed in never smokers.
In this cross-sectional study of an adult general population, self-reported exposure to environmental tobacco smoke, but not self-reported exposure to wood stoves, candles or gas cookers, appeared to be associated with an increased prevalence of lower airway symptoms and decreased lung function.
Book description: In this cross-disciplinary research David Ormandy and expert contributors explain the nature and development of the World Health Organization's study of housing across Europe. In-depth analysis provides new evidence of links between the health of inhabitants and their housing conditions, with focus on critical topics such as:
* indoor air pollution
* the effect of cold homes and dampness
* noise effects
* domestic accidents.
With practical examples of survey tools, the attention given to methodological approaches makes this text an important resource for policy professionals as well as housing, planning and public health academics.
In a cohort of 849 infants with an asthmatic sibling, the authors examined the relations of exposure to allergens (dust mite, cockroach, cat, and dog), nitrogen dioxide, and mold with symptoms of wheeze and persistent cough in the first year of life (1998-2000). Among infants whose mothers had physician-diagnosed asthma, neither dust mite allergen nor dog allergen was associated with either symptom. Exposure to cockroach allergen (Bla g 1 at >or=2 U/g) modestly increased the risk for wheeze (odds ratio (OR) = 1.87, 95% confidence interval (CI): 0.94, 3.71), and exposure to cat allergen modestly decreased the risk (OR = 0.60, 95% CI: 0.35, 1.03). Among infants of mothers with no asthma history, exposure to gas stoves (OR = 1.50, 95% CI: 1.05, 2.15) and wood-burning stoves (OR = 2.09, 95% CI: 1.12, 3.91) increased the risk of persistent cough. Similarly, measured nitrogen dioxide concentration was associated with persistent cough (OR = 1.21, 95% CI: 1.05, 1.40). Persistent mold affected both infants of mothers with asthma (for wheeze, OR = 2.27, 95% CI: 1.27, 4.07; for cough, OR = 1.83, 95% CI: 1.04, 3.22) and infants of mothers without asthma (for cough, OR = 1.55, 95% CI: 1.04, 2.31). Reported exposure was confirmed by an association of measured fungi with wheeze (OR = 1.23, 95% CI: 1.01, 1.49). This appears to have been the first study to measure all of these home exposures (indoor allergens, nitrogen dioxide, fungi) and to prospectively measure the frequency of infant wheeze and persistent cough.
This prospective study investigated the association of exposure to indoor secondary heating sources with otitis media and recurrent otitis media risk in infants.
We enrolled mothers living in nonsmoking households and delivering babies between 1993 and 1996 in 12 Connecticut and Virginia hospitals. Biweekly telephone interviews during the first year of life assessed diagnoses from doctors' office visits and use of secondary home heating sources, air conditioner use, and day care. Otitis media episodes separated by more than 21 days were considered to be unique episodes. Recurrent otitis media was defined as 4 or more episodes of otitis media. Repeated-measures logistic regression modeling evaluated the association of kerosene heater, fireplace, or wood stove use with otitis media episodes while controlling for potential confounders. Logistic regression evaluated the relation of these secondary heating sources with recurrent otitis media.
None of the secondary heating sources were associated with otitis media or with recurrent otitis media. Otitis media was associated with day care, the winter heating season, birth in the fall, white race, additional children in the home, and a maternal history of allergies in multivariate models. Recurrent otitis media was associated with day care, birth in the fall, white race, and a maternal history of allergies or asthma.
We found no evidence that the intermittent use of secondary home heating sources increases the risk of otitis media or recurrent otitis media. This study confirms earlier findings regarding the importance of day care with respect to otitis media risk.
Socioeconomic status (SES) may contribute to the trajectory of pulmonary function over the life course. Studies suggest that people with lower (versus higher) SES during childhood subsequently have lower levels of adult pulmonary function. But prospective studies are sparse across young adulthood, an important phase in pulmonary development.
Participants were from the Coronary Artery (Disease) Risk Development in (Young) Adults (CARDIA) study: 5113 young adults ages 18-30 at baseline, approximately balanced within centres across gender, self-identified race/ethnicity (Black, White), and current SES. Childhood SES was ascertained from baseline self-reports of parents' highest completed education. Pulmonary function in young adulthood was measured using FEV(1) (forced expiratory volume in one second) and FVC (forced vital capacity), assessed on three occasions over a period of 5 years.
Longitudinal analyses suggested that rates of change in both FEV(1) and FVC differed in a gradient fashion by childhood SES. As shown by significant childhood SES by time interaction terms, these associations with FEV(1) were robust for men (b = 1.59E-3, SE = 5.21E-4, P < 0.001) and women (b = 1.93E-3, SE = 4.80E-4, P < 0.001), and adjusted for multiple potential confounders including smoking. Results were similar for FVC. Subsequent examination of the interaction terms suggested that FEV(1) and FVC declined for participants in the lowest childhood SES group, showed continued plateau or growth for those in the highest group, and were intermediate for the middle group.
Childhood SES may influence men's and women's young adult pulmonary function in two ways. First, individuals with lower childhood SES may not attain as high levels of pulmonary function in early adulthood relative to individuals with higher childhood SES. Second, pulmonary function may decline earlier and faster for individuals with lower childhood SES.
Effects of nitrogen dioxide (NO2) on respiratory health have been the subject of extensive research. The outcomes of these studies were not consistent. Exposure to nitrous acid, which is a primary product of combustion, and is also formed when NO2 reacts with water, may play an important role in respiratory health. We estimate the independent effects of exposure to nitrogen dioxide and nitrous acid on respiratory symptoms during the first year of life.
Nitrogen dioxide and nitrous acid concentrations were measured once (1996-1998) in the homes of 768 infants who were at risk for developing asthma. Infants were living in southern New England. The frequency of respiratory symptoms in these children was recorded during the first year of life.
Infants living in homes with an NO2 concentration exceeding 17.4 ppb (highest quartile) had a higher frequency of days with wheeze (rate ratio = 2.2; 95% confidence interval = 1.4-3.4), persistent cough (1.8; 1.2-2.7), and shortness of breath (3.1; 1.8-5.6) when compared with infants in homes that had NO2 concentrations lower than 5.1 ppb (lowest quartile), controlling for nitrous acid concentration. Nitrous acid exposure was not independently associated with respiratory symptoms.
Among infants at risk for developing asthma, the frequency of reported respiratory symptoms in the first year of life was associated with levels of NO2 not currently considered to be harmful.
Knowledge of respiratory diseases in an arctic population with increasingly westernized lifestyles provides the opportunity to obtain new information in this field.
To investigate the influence of environment and lifestyle on the presence of respiratory symptoms in a genetically homogenous population sample living under widely differing conditions.
Greenland is a part of Denmark, but its climate is mainly arctic, as opposed to the temperate climate of southern Denmark. A random sample of Inuits who had immigrated to Denmark and Inuits from 3 towns and 4 remote settlements in Greenland were studied. Of the 6,695 invited Inuits, 4,162 (62%) completed a questionnaire concerning respiratory symptoms and risk factors.
Of the 4,162 Inuits, 847 (20%) had respiratory symptoms. Bronchitis was more frequent in the areas of Greenland than in Denmark (26% and 20% vs 13%; P < .001), whereas the pattern of asthma was contradictory (6% and 9% vs 10%; P = .057). Bronchitis was associated with living area (P = .01), tobacco consumption (P < .001), and asthma (P = .001), whereas asthma was related to living area (P = .03), hay fever (P < .001), low intake of whale (P = .04), years in Denmark (P = .09), and bronchitis (P < .001).
Inuits' prevalence of bronchitis and asthma differed, with a higher frequency of bronchitis and a lower frequency of asthma in Inuits living in Greenland compared with Denmark. Living conditions or areas, diet, tobacco use, climate, and atopy are important for the presence of symptoms.
Further evidence for the role of indoor pollutants in the development of childhood asthma
The prevalence of asthma (especially childhood asthma) is high, and children in particular spend a lot of time in their homes. In addition, our homes contain many pollutants so, understandably, we’d like to know to what extent pollutants in the home environment cause and/or worsen asthma in our children.
In many children asthma is closely associated with allergy, and many asthmatic children are allergic to dust mite and pet allergens. For them, reduction of exposure is likely to be beneficial. But does this mean that mite and pet exposure causes asthma? This issue is surprisingly complex. Whereas studies suggest that exposure to specific allergens increases sensitisation to those allergens, this does not necessarily mean that such exposures also increase the incidence of asthma.1,2 Some studies even suggest that early life exposure to pets (and other animals) may reduce the incidence of asthma.3–7
Compared with the already complex role of exposure to allergens and other biological contaminants, the evidence with respect to chemicals such as nitrogen oxides, sulfur oxides, and particles produced by combustion appliances, environmental tobacco smoke, and volatile organic compounds (VOCs) is even less clear.
In this issue of Thorax two new studies from Australia attempt to provide further evidence for the role of unvented heating appliances and of VOCs, respectively. Phoa et al 8 retrospectively collected data on unvented heater exposure in a sample of children aged 8–11 …
Secondary heating appliances are important indoor sources of air pollution, including particulate matter, nitrogen dioxide (NO2), and sulfur dioxide (SO2). We hypothesized that the use of secondary heating sources increases respiratory symptoms in women living in nonsmoking households and specifically that concentrations of SO2 and NO2 emitted from heating sources are associated with respiratory symptoms.
Mothers who delivered babies at 12 hospitals in Connecticut and Virginia (1993-1996) were enrolled. There were 888 women who contributed symptom and exposure information during the winter heating season (15 October to 15 April), for a total of 9783 reporting periods (median = 12 reporting periods per woman, interquartile range 11-12). Adjusted rate ratios (RRs) of effects of source use and measured concentrations on rate of days with symptoms were obtained using generalized estimating equations for a log-linear Poisson model, controlling age, education, race, history of allergies, number of children, dwelling type, and residence state.
In adjusted models, each hour-per-day increase in kerosene heater use is associated with an increase in wheezing (RR = 1.06; 95% confidence interval (CI) = 1.01-1.11). Each hour of fireplace use is associated with increased cough (1.05; 1.01-1.09), sore throat (1.04; 1.00-1.08), and marginally with chest tightness (1.05; 0.99-1.12). Each 10 ppb increase in SO2 (a proxy for sulfate aerosol) is associated with increased wheezing (1.57; 1.10-2.26) and chest tightness (1.32; 1.01-1.71).
Emissions from fireplaces, gas space heaters, and kerosene heaters may contribute to respiratory symptoms in a population of nonsmoking women.
To investigate if exposure to firewood smoke and other indoor pollutants is a potential risk factor for obstructive airways disease (OAD) among women in Bogota in whom cigarette smoking and other known risk factors may not be the most frequent.
We conducted a hospital-based case-control study to identify risk factors for OAD among women in Bogota. An interview was conducted using a modified questionnaire recommended by the American Thoracic Society for epidemiologic studies.
We compared 104 OAD cases with 104 controls matched by hospital and frequency matched by age.
The odds ratio (OR) was used as the basic statistic to evaluate risk. Multivariate analysis (MA) was conducted by the Mantel-Haenszel procedure and by logistic regression.
Univariate analysis showed that tobacco use (OR = 2.22; p < 0.01), wood use for cooking (OR = 3.43; p < 0.001), passive smoking (OR = 2.05; p = 0.01), and gasoline use for cooking (OR = 0.52; p = 0.02) were associated with OAD. Trends for years of tobacco use and years of wood cooking were present (p < 0.05). After MA, variables remained significant except gasoline use.
This study showed that among elderly women of low socioeconomic status in Bogota, woodsmoke exposure is associated with the development of OAD and may help explain around 50% of all OAD cases. The role of passive smoking remains to be clarified. This work may set the basis for interventional studies in similar settings.
To investigate the relation between different types of heating and the prevalence of atopic diseases, skin test reactivity, and bronchial hyperresponsiveness.
Cross sectional survey among school-children aged 9-11 years. Skin prick tests, pulmonary function tests, and bronchial challenge in the children and self completion of a written questionnaire by the children's parents.
1958 children in a rural area in southern Bavaria, Germany.
Prevalence of asthma, hay fever, and atopic dermatitis as determined by parents' answers to a questionnaire; the atopic status of the child assessed by skin prick tests; and bronchial responsiveness to cold air challenge in the children.
After possible confounders were controlled for, the risk of developing hay fever (odds ratio = 0.57; 95% confidence interval 0.34 to 0.98), atopy defined as at least one positive reaction to a panel of common aeroallergens (0.67; 0.49 to 0.93), sensitisation to pollen (0.60; 0.41 to 0.87), and of bronchial hyperresponsiveness (0.55; 0.34-0.90) was significantly lower in children living in homes where coal or wood was used for heating than in children living in homes with other heating systems.
Factors directly or indirectly related to the heating system used in rural Bavarian homes decrease the susceptibility of children to becoming atopic and to developing bronchial hyperresponsiveness.
The relation between air pollution and the exacerbation of childhood asthma was studied in a panel of 71 children (aged 5 to 7 yr) with mild asthma who resided in the northern part of mexico City. During the follow-up, ambient measures of particulate matter less than 10 microns (PM10, 24-h average) and ozone (1-h maximum) frequently exceeded the Mexican standards for these contaminants. The peak expiratory flow rate (PEFR) was strongly associated with PM10 levels and marginally with ozone levels. Respiratory symptoms (coughing, phlegm production, wheezing, and difficulty breathing) were associated with both PM10 and ozone levels. An increase of 20 micrograms/m3 of PM10 was related to an 8% increase in lower respiratory illness (LRI) among children on the same day (95% confidence interval [CI] = 1.04-1.15), and an increase of 10 micrograms/m3 in the weekly mean of particulate matter less than 2.5 microns (PM2.5) was related to a 21% increase in LRI (95% CI = 1.08-1.35). A 50 parts per billion (ppb) increase in ozone was associated with a 9% increase in LRI (95% CI = 1.03-1.15) on the same day. We concluded that children with mild asthma are affected by the high ambient levels of particulate matter and ozone observed in the northern part of Mexico City.
This paper examines the associations between average daily particulate matter less than 10 microns in diameter (PM10) and temperature with daily outpatient visits for respiratory disease including asthma, bronchitis, and upper respiratory illness in Anchorage, Alaska, where there are few industrial sources of air pollution. In Anchorage, PM10 is composed primarily of earth crustal material and volcanic ash. Carbon monoxide is measured only during the winter months. The number of outpatients visits for respiratory diagnoses during the period 1 May 1992 to 1 March 1994 were derived from medical insurance claims for state and municipal employees and their dependents covered by Aetna insurance. The data were filtered to reduce seasonal trends and serial autocorrelation and adjusted for day of the week. The results show that an increase of 10 micrograms/m3 in PM10 resulted in a 3-6% increase in visits for asthma and a 1-3% increase in visits for upper respiratory diseases. Winter CO concentrations were significantly associated with bronchitis and upper respiratory illness, but not with asthma. Winter CO was highly correlated with automobile exhaust emissions. These findings are consistent with the results of previous studies of particulate pollution in other urban areas and provide evidence that the coarse fraction of PM10 may affect the health of working people.
There is growing concern about health effects of air pollution in the UK. Studies in the USA have reported adverse effects on lung function among children but no comparable studies have been published in the UK. This study investigates the relationship between daily changes in ambient air pollution and short term variations in lung function in a panel of school children.
One hundred and fifty four children aged 7-11 attending a primary school adjacent to a major motorway in Surrey, south-east England, were studied. Bellows spirometry was performed daily on 31 schooldays between 6 June and 21 July 1994. Levels of ozone, nitrogen dioxide, and particulates of less than 10 microns in diameter (PM10) were measured continuously at the school and the pollen count was measured six miles away. Relationships between daily changes in forced expiratory volume in 0.75 seconds (FEV0.75), forced vital capacity (FVC), the FEV0.75/FVC ratio and pollutants were analysed using separate autoregressive models for each child. A weighted average of the resulting slopes was then calculated.
There was a significant inverse relationship between daily mean PM10 levels lagged one day and FVC, with a reduction in lung function of 1% (95% CI 0.3% to 2%) across the whole range of PM10 levels (20-150 micrograms/m3). The effect on FEV0.75 was similar (-0.5%) but was not significant when weighted by 1/SE2 (95% CI -1.2% to 0.2%). There was no effect of PM10 levels on the FEV0.75/FVC ratio. No significant association was seen between FEV0.75, FVC, or the FEV0.75/FVC ratio and either ozone or nitrogen dioxide levels. There was no evidence that wheezy children were more affected than healthy children. Pollen levels on the previous day had no effect on lung function and did not change the air pollution results.
There is a very small, but statistically significant, adverse effect of airborne respirable particulate matter, measured as PM10, on lung function in this study group. There is no evidence for an inverse association of lung function with levels of ozone or NO2 measured on the previous day.
The association between fine and ultrafine particles and respiratory health was studied in adults with a history of asthma in Erfurt, Eastern Germany. Twenty-seven nonsmoking asthmatics recorded their peak expiratory flow (PEF) and respiratory symptoms daily. The size distribution of ambient particles in the range of 0.01 to 2.5 microm was determined with an aerosol spectrometer during the winter season 1991-1992. Most of the particles (73%) were in the ultrafine fraction (smaller than 0.1 microm in diameter), whereas most of the mass (82%) was attributable to particles in the size range of 0.1 to 0.5 microm. Because these two fractions did not have similar time courses (correlation coefficient r = 0.51), a comparison of their health effects was possible. Both fractions were associated with a decrease of PEF and an increase in cough and feeling ill during the day. Health effects of the 5-d mean of the number of ultrafine particles were larger than those of the mass of the fine particles. In addition, the effects of the number of the ultrafine particles on PEF were stronger than those of particulate matter smaller than 10 microm (PM10). Therefore, the present study suggests that the size distribution of ambient particles helps to elucidate the properties of ambient aerosols responsible for health effects.
Short-term effects of air pollution (consisting primarily of sulphur dioxide and particulate matter but with low acidity) on respiratory morbidity were studied in asthmatic children from Sokolov, Czech Republic. Eighty nine children with asthma, who recorded daily peak expiratory flow measurements, symptoms and medication use in a diary, were analysed for 7 months during the winter of 1991-1992. Air pollution measurements included: SO2, total suspended particulates (TSPs), inhalable particles, ie. particulate matter of aerodynamic diameter < or = 10 microm, particle strong acidity (PSA) and fine particle sulphate concentration (SO4). Linear and logistic regression analyses estimated the impact of air pollutants adjusted for trend, temperature and weekend and autocorrelated errors. Exposure to elevated levels of air pollution was associated with decreased peak expiratory flow rates, increased respiratory symptoms, increased prevalence of school absence and fever, and increased medication use. Prolonged exposure to particle SO4 showed the largest effect estimates. At the end of January, an air pollution episode occurred, during which respiratory symptoms, prevalence of fever, school absence and asthma medication increased. The association between respiratory symptoms and particulate SO4 was highly dependent on this episode, whilst the associations between lung function and SO4 as well as between fever and SO4 were still observed when this air pollution episode was excluded. Some evidence was found that exposure to air pollution might have enhanced the respiratory symptoms while children were experiencing respiratory infections. In this study, a panel of children with mild asthma experienced small decreases in peak expiratory flow and increased dyspnoea in association with fine particles formed during air pollution episodes.
Previous controlled studies have indicated that asthma medication modifies the adverse effects of sulfur dioxide (SO2) on lung function and asthma symptoms. The present report analyzed the role of medication use in a panel study of children with mild asthma. Children from Sokolov (n = 82) recorded daily peak expiratory flow (PEF) measurements, symptoms, and medication use in a diary. Linear and logistic regression analyses estimated the impact of concentrations of sulfate particles with diameters less than 2.5 microns, adjusting for linear trend, mean temperature, weekend (versus weekday), and prevalence of fever in the sample. Fifty-one children took no asthma medication, and only 31 were current medication users. Most children were treated with theophylline; only nine used sprays containing beta-agonist. For the nonmedicated children, weak associations between a 5-day mean of sulfates and respiratory symptoms were observed. Medicated children, in contrast, increased their beta-agonist use in direct association with an increase in 5-day mean of sulfates, but medication use did not prevent decreases in PEF and increases in the prevalence of cough attributable to particulate air pollution. Medication use was not a confounder but attenuated the associations between particulate air pollution and health outcomes.
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Exacerbations of asthma have been associated with exposure to ozone or particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10). We postulated in this study that the association of summertime air pollution (i.e. ozone and PM10) with acute respiratory symptoms, medication use and peak expiratory flow differs among patients grouped according to asthma severity. During the summer of 1995, effects of ambient air pollution on these parameters were studied in a panel of 60 nonsmoking patients with intermittent to severe persistent asthma. These patients were recruited from our Pulmonary Out-patient Clinic. Subgroup analysis was performed on the degree of hyperresponsiveness and lung steroid use before the start of the study, as indictors for the severity of asthma. Associations of the parameters studied with ozone, PM10, nitrogen dioxide (NO2), sulphur dioxide (SO2) and black smoke were evaluated using time series analysis. Several episodes with increased summertime air pollution occurred during the 96 day study period. Eight hour average ozone concentrations exceeded the World Health Organization (WHO) Air Quality Guidelines (120 microg x m(-3)) on 16 occasions. Daily mean levels of PM10 were moderately elevated (range 16-98 microg x m(-3)). Levels of the other measured pollutants were low. There was a consistent, positive association of the prevalence of shortness of breath (maximal relative risk (RRmax) 1.18) with ozone, PM10, black smoke and NO2. In addition, bronchodilator use was associated with both ozone and PM10 levels (RRmax 1.16). Stratification by airway hyperresponsiveness and steroid use did not affect the magnitude of the observed associations. No associations with peak expiratory flow measurements were found. We conclude that the severity of asthma is not an indicator for the sensitivity to air pollution.
Many epidemiological studies conducted in the last several years have reported associations between exposure to airborne particulate matter, measured as PM10 (<10 microm in diameter), and daily morbidity and mortality. However, much of the evidence involves effects on the elderly population; there is less evidence about the effects of particulates on children, especially those under 2 years of age. To examine these issues, we conducted time-series analyses of 2 years of daily visits to primary health care clinics in Santiago, Chile, where counts were computed for either upper or lower respiratory symptoms and for cohorts of children 3-15 years of age and below age 2. Daily PM10 and ozone measurements and meteorological variables were available from instruments located in downtown Santiago. The multiple regression analysis indicates a statistically significant association between PM10 and medical visits for lower respiratory symptoms in children ages 3-15 and in children under age 2. PM10 is also associated with medical visits related to upper respiratory symptoms in the older cohort, while ozone is associated with visits related to both lower and upper respiratory symptoms in the older cohort. For children under age 2, a 50- microg/m3 change in PM10 (the approximate interquartile range) is associated with a 4-12% increase in lower respiratory symptoms. For children 3-15 years of age, the increase in lower respiratory symptoms ranges from 3 to 9% for a 50- microg/m3 change in PM10 and 5% per 50 ppb change in ozone. These magnitudes are similar to results from studies of children undertaken in Western industrial nations.
Many epidemiological studies have shown positive short-term associations between health and current levels of outdoor air pollution. The aim of this study was to investigate the association between air pollution and the number of visits to accident and emergency (A&E) departments in London for respiratory complaints. A&E visits include the less severe cases of acute respiratory disease and are unrestricted by bed availability. Daily counts of visits to 12 London A&E departments for asthma, other respiratory complaints, and both combined for a number of age groups were constructed from manual registers of visits for the period 1992-1994. A Poisson regression allowing for seasonal patterns, meteorological conditions and influenza epidemics was used to assess the associations between the number of visits and six pollutants: nitrogen dioxide, ozone, sulphur dioxide, carbon monoxide, and particles measured as black smoke (BS) and particles with a median aerodynamic diameter of <10 microm (PM10). After making an allowance for the multiplicity of tests, there remained strong associations between visits for all respiratory complaints and increases in SO2: a 2.8% (95% confidence interval (CI) 0.7-4.9) increase in the number of visits for a 18 microg x (-3) increase (10th-90th percentile range) and a 3.0% (95% CI 0.8-5.2) increase for a 31 microg x m(-3) increase in PM10. There were also significant associations between visits for asthma and SO2, NO2 and PM10. No significant associations between O3 and any of the respiratory complaints investigated were found. Because of the strong correlation between pollutants, it was difficult to identify a single pollutant responsible for the associations found in the analyses. This study suggests that the levels of air pollution currently experienced in London are linked to short-term increases in the number of people visiting accident and emergency departments with respiratory complaints.
Active smoking is the most important risk factor for pulmonary emphysema in subjects with severe alpha 1-antitrypsin (AAT) deficiency. The aim of this study was to analyse the effects of environmental risk factors other than active smoking on lung function and on respiratory symptoms in non-smoking PiZZ individuals.
Lifetime exposure to passive smoking, domiciliary use of a kerosene (paraffin) heater or gas cooker, and all occupations since leaving school were reported by 205 non-smoking PiZZ individuals (95 men and 110 women) included in the Swedish AAT deficiency register. Lung function test results and histories of respiratory symptoms (chronic bronchitis, recurrent wheezing, and exertional dyspnoea) were elicited from the AAT register records.
After adjustment for age, agricultural employment and domiciliary kerosene heater usage, but not gas cooker usage or passive smoking, were both associated with significantly decreased lung function. Multiple linear regression analysis showed age, sex, kerosene heater usage, and agricultural employment to be independent determinants of lung function impairment. Age and passive smoking for 10 years or more, both at home and at the work place, were associated with the presence of chronic bronchitis. Age and agricultural employment for > or = 10 years were associated with recurrent wheezing and exertional dyspnoea.
Domiciliary kerosene heater usage and an agricultural occupation therefore appear to be environmental factors associated with decreased lung function in non-smoking PiZZ individuals, and passive smoking is associated with an increased frequency of chronic bronchitis, but not with impaired lung function.
Asthma is the most common chronic illness of childhood and its prevalence is increasing, causing much concern for identification of risk factors such as air pollution. We previously conducted a study showing a relationship between asthma visits in all persons < 65 years of age to emergency departments (EDs) and air pollution in Seattle, Washington. In that study the most frequent zip codes of the visits were in the inner city. The Seattle-King County Department of Public Health (Seattle, WA) subsequently published a report which showed that the hospitalization rate for children in the inner city was over 600/100,000, whereas it was < 100/100,000 for children living in the suburbs. Therefore, we conducted the present study to evaluate whether asthma visits to hospital emergency departments in the inner city of Seattle were associated with outdoor air pollution levels. ED visits to six hospitals for asthma and daily air pollution data were obtained for 15 months during 1995 and 1996. The association between air pollution and childhood ED visits for asthma from the inner city area with high asthma hospitalization rates were compared with those from lower hospital utilization areas. Daily ED counts were regressed against fine particulate matter (PM), carbon monoxide (CO), sulfur dioxide, and nitrogen dioxide using a semiparametric Poisson regression model. Significant associations were found between ED visits for asthma in children and fine PM and CO. A change of 11 microg/m3 in fine PM was associated with a relative rate of 1.15 [95% confidence interval (CI), 1.08-1.23]. There was no stronger association between ED visits for asthma and air pollution in the higher hospital utilization area than in the lower utilization area. These findings were seen when estimated PM2.5 concentrations were below the newly adopted annual National Ambient Air Quality Standard of 15 microg/m3.
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The very young and elderly are most vulnerable to health impairments 'secondary' to air pollution. A study was conducted in the winter of 1985-1986 to analyze the impact of woodstove burning on the general respiratory health of pre-school children living in homes where wood was burned. There was no attempt to separate out the potential impacts from the various types of woodstoves, for example, airtight or catalytic filters. The frequency and severity of 10 respiratory symptoms in 59 children were recorded by parents over a six-week period. The study focused on eliciting symptoms of upper respiratory tract irritations and upper respiratory illness. Data analysis yielded a significant correlation between hours of woodstove use and wheeze frequency, wheeze severity, cough frequency and waking up with cough (P = 0.01). The correlation between woodstove use and cough severity was significant at the P = 0.05 level. No evidence was found suggesting an association between hours of woodstove use and the symptoms of fever, shortness of breath or runny nose.
• Some studies suggest that home use of wood-burning stoves is an independent risk factor for lower respiratory tract infection in young children. To test this hypothesis in a population with a high prevalence of wood-burning stove use, we studied Navajo children with diagnosed pneumonia or bronchiolitis. We matched each case (≤24 months of age) with a child of identical sex and age who was seen for well-child care or a minor health problem, and we interviewed an adult caretaker about family history and environmental exposures. Analyzing 58 case-control pairs, we found that home wood-burning stove use, recent respiratory illness exposure, family history of asthma, dirt floors, and lack of running water in the home increased the risk of lower respiratory tract infection. On multiple logistic regression analysis, however, only wood-burning stove use and respiratory illness exposure were independently associated with higher risk.
(AJDC. 1990;144:105-108)
Background: Acute lower respiratory illnesses (ALRI) have been associated with exposure to domestic smoke. To examine further this association, a case-control study was conducted among Navajo children seen at the Public Health Service Indian Hospital at Fort Defiance, AZ.
Methods: Cases, children hospitalized with an ALRI (n = 45), were ascertained from the inpatient logs during October, 1992, through March, 1993. Controls, children who had a health record at the same hospital and had never been hospitalized for ALRI, were matched 1:1 to cases on date of birth and gender. Home interviews of parents of subjects during March and April, 1993, elicited information on heating and cooking fuels and other household characteristics. Indoor air samples were collected for determination of time-weighted average concentrations of respirable particles (i.e. <10 μm in diameter).
Results: Age of cases at the time of admission ranged from 1 to 24 months (median, 7 months); 60% of the cases were male. Matched pair analysis revealed an increased risk of ALRI for children living in households that cooked with any wood (odds ratio (OR), 5.0; 95% confidence interval (CI), 0.6 to 42.8), had indoor air concentrations of respirable particles ≥65 μg/m3 (i.e. 90th percentile) (OR 7.0, 95% CI 0.9 to 56.9), and where the primary caretaker was other than the mother (OR 9, 95% CI 1.1 to 71.4). Individual adjustment for potential confounders resulted in minor change (i.e. <20%) in these results. Indoor air concentration of respirable particles was positively correlated with cooking and heating with wood (P < 0.02) but not with other sources of combustion emissions.
Conclusions: Cooking with wood-burning stoves was associated with higher indoor air concentrations of respirable particles and with an increased risk of ALRI in Navajo children.
We assessed the contributions of particulate matter with aerodynamic diameters less than or equal to 10 and less than or equal to 2.5 mu m (PM2.5 and PM10) and ozone (O-3) to peak expiratory flow (PEF) and respiratory symptoms in 40 schoolchildren 8-11 years of age for 59 days during three periods in 1991 at a school in southwest Mexico City. We measured peak expiratory flow in the morning on the children's arrival at school and in the afternoon before their departure from school. Separately for morning and afternoon, we normalized each child's daily measurement of peak flow by subtracting his or her mean peak flow from the daily measurement. Child-specific deviations were averaged to obtain a morning and afternoon mean deviation (Delta PEF) for each day. Mean 24-hour O-3 level was 52 parts per billion (ppb; maximum 103 ppb); mean 24-hour PM2.5 and PM10 were 30 mu g/m(3) (maximum 69 mu g/m(3)) and 49 mu g/m(3) (maximum 81 mu g/m(3)), respectively. We adjusted moving average and polynomial distributed lag multiple regression analyses of Delta PEF us pollution for minimum daily temperature, trend, and season. We examined effects of PM2.5, PM10, and O-3, on Delta PEF separately and in joint models. The models indicated a role for both particles and O-3 in the reduction of peak expiratory flow, with shorter lags between exposure and reduction in peak expiratory flow for O-3 than for particle exposure (0-4 vs 4-7 days). The joint effect of 7 days of exposure to the interquartile range of PM2.5 (17 mu g/m(3)) and O-3 (25 ppb) predicted a 7.1% (95% confidence interval = 11.0-3.9) reduction in morning peak expiratory flow. Pollutant exposure also predicted higher rates of phlegm; colinearity between pollutants limited the potential to distinguish the relative contribution of individual pollutants. In an area with chronically high ambient O-3 levels, school children responded with reduced lung function to both O-3 and particulate exposures within the previous 1 to 2 weeks.
The article discusses chamber studies of four unvented kerosene space heaters to assess emissions of total particle, sulfate, and acidic aerosol. The heaters tested represented four burner designs currently in use by the public. Kerosene space heaters are a potential source of fine particles (= or < 2.5 micrometer diameter), sulfate, and acidic aerosol indoors. Fine particle concentrations in houses in which the heaters are used may be increased in excess of 20 micrograms/m3 over background levels. Sulfate and acidic aerosol levels in such houses could exceed average and peak outdoor concentrations. Maltuned heaters could produce exceptionally high levels of all air contaminants measured.
A prospective epidemiologic study was carried out for 12 weeks in the winter of 1983 to evaluate the impact of indoor air contaminant levels on respiratory health. A group of 121 children below the age of 13 (59 with unvented kerosene space heaters in the home; 62 without) were enrolled in the study and nitrogen dioxide levels were measured in 93% of the subjects' homes for one two-week period. When socioeconomic status and history of respiratory illness were controlled, children under the age of seven exposed to 30 μg/m3 or more of nitrogen dioxide were found to have a risk of reporting lower respiratory symptoms 2.25 times (95% C.I. 1.69–4.79) that of children who were not exposed. Aspects of our study design, including increased precision of exposure classification and the inclusion of very young children, may explain our findings.
The effect of maternal smoking during pregnancy on the morbidity and mortality of the child up to the age of five was studied in 12068 births. The children of the smokers were compared with those of controls of similar age, parity, marital status and place of residence. Perinatal mortality was no higher among the smokers, but postneonatal mortality from 28 days to 5 years was almost significantly (p less than 0.05) higher. The children of the smokers were highly significantly (p less than 0.001) more often hospitalized in pediatric departments, the difference being clearest below the age of one. The average duration of hospital admissions was longer among the children of the smokers, and similarly the numbers of visits to the doctor and hospital admissions to any hospital under the age of one were more frequent among the children of the smokers. Respiratory diseases caused highly significantly more hospitalizations among these children.
The use of meta-analysis is becoming more common in the medical literature, but it is not common in the environmental literature. Although meta-analysis cannot combine a group of poorly executed, conflicting studies to get an unequivocal answer, there are certain situations where it can be helpful. The inability of studies to produce similar results may be a function of the power of the studies rather than a reflection of their quality. The literature on the effects of nitrogen dioxide on the odds of respiratory illness in children is such an example. Three quantitative methods for the synthesis of this evidence are presented. Although the methods produce slightly different results, the conclusion from all three methods is that the increase in the odds of respiratory illness in children exposed to a long-term increase of 30 micrograms/m3 (comparable to the increase resulting from exposure to a gas stove) is about 20 percent. This estimated increase is not sensitive to the method of analysis.
The effect of indoor nitrogen dioxide on the cumulative incidence of respiratory symptoms and pulmonary function level was studied in a cohort of 1,567 white children aged 7-11 years examined in six US cities from 1983 through 1988. Week-long measurements of nitrogen dioxide were obtained at three indoor locations over 2 consecutive weeks in both the winter and the summer months. The household annual average nitrogen dioxide concentration was modeled as a continuous variable and as four ordered categories. Multiple logistic regression analysis of symptom reports from a questionnaire administered after indoor monitoring showed that a 15-ppb increase in the household annual nitrogen dioxide mean was associated with an increased cumulative incidence of lower respiratory symptoms (odds ratio (OR) = 1.4, 95% confidence interval (95% Cl) 1.1-1.7). The response variable indicated the report of one or more of the following symptoms: attacks of shortness of breath with wheeze, chronic wheeze, chronic cough, chronic phlegm, or bronchitis. Girls showed a stronger association (OR = 1.7, 95% Cl 1.3-2.2) than did boys (OR = 1.2, 95% Cl 0.9-1.5). An analysis of pulmonary function measurements showed no consistent effect of nitrogen dioxide. These results are consistent with earlier reports based on categorical indicators of household nitrogen dioxide sources and provide a more specific association with nitrogen dioxide as measured in children's homes.
This case-control study investigated the possible association between home environmental air pollutants and their effect on otitis media and asthma in children. Patients with physician-diagnosed otitis (n = 125, 74% response), with asthma (n = 137, 80% response), and controls (n = 237, 72% response) from a private pediatric practice seen between October 1986 and May 1987 were studied. A questionnaire inquired about housing characteristics (i.e., age, insulation, heating system) and sources of indoor air pollution such as cigarette smoking, use of woodburning stoves, household pets, etc. Analysis of the responses confirmed previous findings of significant relationships between maternal smoking (P = .021), and the presence of pets (P = .034) and the occurrence of asthma. A newly reported relationship between exposure to woodburning stoves and the occurrence of otitis (P less than .05) was reported. This implicates yet another risk factor (wood burning) in the etiology of otitis media.
Suggested aetiological factors were evaluated in 244 consecutive children presenting with lower respiratory disease at Marondera Hospital, Zimbabwe. Data obtained from these children were compared with information obtained from 500 children seen at the local well baby clinic. There were no differences in the prevalence of malnutrition, breast feeding, overcrowding, poor housing conditions and poverty in these two groups of children. A significant association was identified between lower respiratory disease and exposure to atmospheric woodsmoke pollution in young children. Air sampling within the kitchens of 40 children revealed levels of atmospheric pollution far in excess of the WHO recommended exposure limit. Elevated carboxyhaemoglobin concentrations confirmed childhood smoke inhalation. We suggest that in many Third World communities a chemical pneumonitis resulting from the inhalation of noxious constituents of woodsmoke predisposes to lower respiratory disease in children.
The health effects of both indoor and outdoor air pollutants are of increasing concern. The health effects of outdoor air pollutants traditionally have been assessed through measurements of lower respiratory tract changes. However, it has been shown that one outdoor air pollutant, sulfur dioxide, decreases nasal mucus flow and increases nasal airway resistance. Along with cigarette smoke, indoor air pollutants such as formaldehyde, cadmium, and ammonium or sulfate ions have been shown to alter upper airway mucociliary function. Emissions from wood stoves are known to irritate the upper airways. Measurement of nasal airway resistance using posterior rhinomanometry allows quantification of nasal function. This technique recently has been used to demonstrate that adolescents with allergic asthma have increased work of breathing after inhalation of 0.5 ppm sulfur dioxide. Another study using posterior rhinomanometry showed that clerical workers had increased work of breathing after exposure to carbonless copy paper as compared with bond paper. This brief review of upper respiratory tract changes after pollutant exposure should serve as a reminder that a complete clinical history must include questions designed to ascertain the patient's exposure history to both outdoor and indoor air pollutants. These exposures can have a major impact on the health of the upper respiratory system.
In 1977 an association was reported between the prevalence of respiratory illness and use of gas for cooking at home in a national sample of six to 11 year olds living in England and Scotland (p less than .10). Other variables such as social class and number of cigarette smokers at home did not seem to explain the association. As the gas cooker is an unflued appliance emitting a variety of pollutants during gas combustion it was suggested that indoor air pollution might explain the finding. Nitrogen dioxide (NO2) was suspected so a series of studies was conducted to investigate the distribution of levels of NO2 in the home, the relative contribution of sources of NO2 to indoor exposure and the relation between respiratory illness in six to 11 year olds and levels of NO2 in the home. The gas cooker was found to be one of the main sources of NO2 in the home. Winter weekly averages in kitchens with gas cookers had a mean of 112.2 ppb (n = 428, range 5-317 ppb). Levels in electric cooking kitchens were significantly lower (n = 87, mean 18 ppb, range 6-188 ppb). Studies of health indicated a relation between respiratory illness and bedroom levels of NO2 over the range 4-169 ppb (p .10). Results for living room levels of NO2 suggested a similar but non-significant relationship (p greater than .10). No relation was found for kitchen levels of NO2. For schoolchildren any effect on health from indoor NO2 is likely to be weak. However other sections of the population such as infants and the elderly who may spend more time indoors and are particularly susceptible to respiratory illness need to be studied to assess fully the impact that NO2 may be having on health.
Recurrent or persistent lower respiratory disease in children may present in various ways. The differential diagnosis includes reactive airways disease (asthma), prolonged viral pneumonia (in the young infant) and foreign body aspiration-the most common causes of persistent respiratory symptoms. The differential diagnosis also includes a long list of rare conditions. Because of the many diagnostic possibilities, the evaluation of a child with persistent lower respiratory disease should be carried out in a systematic, stepwise fashion.
The occurrence of symptoms of respiratory illness among preschool children living in homes heated by wood-burning stoves was examined by conducting an historical prospective study (n = 62) with an internal control group (matched for age, sex, and town of residence). Exposures of subjects were not significantly different (P greater than .05) with respect to parental smoking, urea-formaldehyde foam insulation, and use of humidifiers. The control group made significantly greater use of gas stoves for cooking whereas the study group made greater use of electric stoves for cooking and of air filters (P less than .05). Only one home used a kerosene space heater. During the winter of 1982, moderate and severe symptoms in all categories were significantly greater for the study group compared with the control group (P less than .001). These differences could not be accounted for by medical histories (eg, allergies, asthma), demographic or socioeconomic characteristics, or by exposure to sources of indoor air pollution other than wood-burning stoves. Present findings suggest that indoor heating with wood-burning stoves may be a significant etiologic factor in the occurrence of symptoms of respiratory illness in young children.
Admissions to hospital during the first year of life were recorded in a prospective study of 10,672 infants whose mothers' smoking habits were known. Infants with major congenital malformations, and those dying before their first birthday, were excluded. The infants of mothers who smoked had significantly more admissions for bronchitis or pneumonia, especially in the winter, and more injuries. They were also admitted more frequently, though not significantly so, for upper-respiratory-tract infections, gastroenteritis, childhood infectious diseases, and other diagnoses. The excess of bronchitis and pneumonia in the group exposed to smoke increased with increasing number of cigarettes smoked by the mother. It occurred within subgroups of birth-weight, social class, and birth order. It was seen mainly in infants aged 6-9 months, while at older and younger ages there was no significant effect of maternal smoking. The findings support the hypothesis that atmospheric pollution with tobacco smoke endangers the health of non-smokers.
This article has no abstract; the first 100 words appear below.
RESPIRATORY infections are the major cause of morbidity due to acute illnesses in the United States.¹ Children may experience six to eight acute respiratory illnesses per year,²³⁴ many of which, particularly in infancy, will involve the lower respiratory tract.⁴,⁵ Mortality resulting from acute lower respiratory disease is a serious problem in children under five years of age.⁶⁷⁸ A large proportion of these illnesses have been ascribed to specific respiratory viruses and Mycoplasma pneumoniae.⁹,¹⁰ Despite this information and the scientific knowledge and technical advances that have led to control of diseases such as poliomyelitis and measles, little progress has been . . .
Supported in part by the Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health (Contract PH 43–67–48), and by a contract (DADA-17–71 -C-1095) with the U. S. Army Medical Research and Development Command under the sponsorship of the Commission on Acute Respiratory Disease of the Armed Forces Epidemiological Board.
We are indebted to the pediatricians of the group practice (Drs. Robert J. Senior, Charles I. Sheaffer and William G. Conley) for their contributions to this work, to our colleagues in the laboratory, Drs. Wallace A. Clyde, Jr., Frank A. Loda, Gerald W. Fernald and Albert M. Collier, and to the many who provided technical assistance, especially Mrs. Ann Y. Williams, M.T.
Source Information
From the Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill, N.C. 27514, where reprint requests should be addressed to Dr. Glezen.
Telephone interviews were completed in Western Massachusetts in April 1983 for 399 households (91.5 per cent) in a random sample of households with elementary school children. Woodstoves were used in 64.7 per cent of the homes, but such use was not associated with acute respiratory illness. However, formaldehyde exposure was significantly related, with a risk ratio of 2.4 (95 per cent confidence interval 1.7-3.4). New construction/remodeling and new upholstered furniture had additive effects. Neither woodstove use nor formaldehyde exposure were significantly associated with asthma, chronic bronchitis, or allergies.
This study investigated the relationship between indoor air quality and the prevalence of respiratory symptoms in South Australian preschool children.
Data were collected from 14,124 families with a child aged 4 years 3 months to 5 years of age. This sample represents 73% of the targeted State preschool population. At the time of a routine preschool health check, parents completed a questionnaire regarding: their child's respiratory health and place of residence (postcode), parental smoking, type of fuel used for cooking and heating and method used for home cooling.
For preschool children residing in the greater Adelaide region, logistic regression analyses found that having a natural gas stove compared to an electric stove was significantly associated with increased prevalence rates for: (i) asthma (odds ratio [OR] 1.24); (ii) wheezing in the preceding 12 months (OR 1.16); excessive colds (OR 1.14); and hay fever (OR 1.13). The use of a liquid petroleum gas stove compared to an electric stove was not associated with any respiratory symptoms. The use of a flueless gas heater compared to other forms of heating was significantly associated with increased prevalence rates for dry cough (OR 1.26), ever having wheezed (OR 1.15) and wheezing in the preceding 12 months (OR 1.18). The use of a wood fire/heater compared to other forms of heating was significantly associated with a reduced prevalence rate for dry cough (OR 0.84) and ever having wheezed (OR 0.82). Parental smoking was significantly associated with increased prevalence rates for bronchitis (OR 1.21) and ever having wheezed (OR 1.24). The form of home cooling used was not associated with prevalence rates, after accounting for geographic location. Socio-economic status (postcode level) was not generally associated with prevalence rates.
These results suggest that respiratory symptom prevalence is related to the fuel used for cooking and heating and parental smoking. Prospective investigation regarding indoor air quality and respiratory symptoms is required.
Many young children wheeze during viral respiratory infections, but the pathogenesis of these episodes and their relation to the development of asthma later in life are not well understood.
In a prospective study, we investigated the factors affecting wheezing before the age of three years and their relation to wheezing at six years of age. Of 1246 newborns in the Tucson, Arizona, area enrolled between May 1980 and October 1984, follow-up data at both three and six years of age was available for 826. For these children, assessments in infancy included measurement of cord-serum IgE levels (measured in 750 children), pulmonary-function testing before any lower respiratory illness had occurred (125), measurement of serum IgE levels at nine months of age (672), and questionnaires completed by the children's parents when the children were one year old (800). Assessments at six years of age included measurement of serum IgE levels (in 460), pulmonary-function testing (526), and skin allergy testing (629).
At the age of six years, 425 children (51.5 percent) had never wheezed, 164 (19.9 percent) had had at least one lower respiratory illness with wheezing during the first three years of life but had no wheezing at six years of age, 124 (15.0 percent) had no wheezing before the age of three years but had wheezing at the age of six years, and 113 (13.7 percent) had wheezing both before three years of age and at six years of age. The children who had wheezing before three years of age but not at the age of six had diminished airway function (length-adjusted maximal expiratory flow at functional residual capacity [Vmax FRC]) both before the age of one year and at the age of six years, were more likely than the other children to have mothers who smoked but not mothers with asthma, and did not have elevated serum IgE levels or skin-test reactivity. Children who started wheezing in early life and continued to wheeze at the age of six were more likely than the children who never wheezed to have mothers with a history of asthma (P < 0.001), to have elevated serum IgE levels (P < 0.01), to have normal lung function in the first year of life, and to have elevated serum IgE levels (P < 0.001) and diminished values for VmaxFRC (P < 0.01) at six years of age.
The majority of infants with wheezing have transient conditions associated with diminished airway function at birth and do not have increased risks of asthma or allergies later in life. In a substantial minority of infants, however, wheezing episodes are probably related to a predisposition to asthma.
A daily diary of respiratory symptoms was collected from the parents of 1,844 school children in six U.S. cities to study the association between ambient air pollution exposures and respiratory illness. A cohort of approximately 300 elementary school children in each of six communities were asked to keep a daily log of the study child's respiratory symptoms for one year. Daily measurements of ambient sulfur dioxide, nitrogen dioxide, ozone, inhalable particles (PM10), respirable particles (PM2.5), light scattering, and sulfate particles were made, along with integrated 24-h measures of aerosol strong acidity. The analyses were limited to the five warm season months between April and August. Significant associations were found between incidence of coughing symptoms and incidence of lower respiratory symptoms and PM10, and a marginally significant association between upper respiratory symptoms and PM10. There was no evidence that other measures of particulate pollution including aerosol acidity were preferable to PM10 in predicting incidence of respiratory symptoms. Significant associations in single pollutant models were also found between sulfur dioxide or ozone and incidence of cough, and between sulfur dioxide and incidence of lower respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)
In conclusion, this review reveals much about the constituents and fate of wood smoke but not enough about the health effects. Animal toxicological studies show that wood smoke exposure can disrupt cellular membranes, depress macrophage activity, destroy ciliated and secretory respiratory epithelial cells, and cause aberrations in biochemical enzyme levels. With respect to the human epidemiological data, the literature summarized in Table 4 shows a coherence of the data from young children, with 7/8 studies especially in children with asthma, reporting increased respiratory symptoms, lower respiratory infection, and decreased pulmonary function as a result of exposure to wood smoke. As Bates (6) has discussed, coherence of the data, although not amenable to statistical tests, carries the weight of linkage and plausibility. These adverse respiratory effects associated with wood smoke exposure also comply with many of Brandon Hill's aspects of association necessary to establish causation (40). There is strength of association, consistency (7/8 studies showing positive associations), temporality, plausibility, coherence, and analogy (using ETS exposure; 70, 94). A biological gradient has not been shown, although one is suggested in the study of pulmonary function in wildfire fighters. We conclude that the preponderance of the data suggest a causal relationship between elevated wood smoke levels and adverse respiratory health outcomes in young children.
There is evidence from some studies that people living in homes with gas stoves and other unvented gas appliances experience more respiratory symptoms than those who use other fuels for cooking and heating, but other studies have found no such association. We have investigated whether the use of gas appliances is associated with an increased risk of respiratory symptoms and whether sensitisation to common environmental allergens modifies any such association.
A stratified random sample of 15,000 adults aged 20-44 years, living in three towns in East Anglia, UK, were sent a questionnaire on asthma and hayfever. From those who responded, a random sample of 1864 were invited to complete an extended questionnaire that included questions on use of gas appliances, to give blood samples for measurements of total IgE and specific IgE to common allergens, and to undergo tests of respiratory function, 659 women and 500 men agreed to an interview. The association of the use of gas appliances with respiratory symptoms, total IgE, specific IgE, and respiratory function was assessed by logistic and multiple regression models.
Women who reported they mainly used gas for cooking had an increased risk of several asthma-like symptoms during the past 12 months including wheeze (odds ratio 2.07 [95% CI 1.41-3.05]), waking with shortness of breath (2.32 [1.25-4.34]), and asthma attacks (2.60 [1.20 -5.6]). Gas cooking increased the risk of symptoms more in women who were atopic than in non-atopic women but the difference did not reach significance (p . 0.05). Women who used a gas stove or had an open gas fire had reduced lung function (forced expiratory volume in 1 s [FEV1]) and increased airways obstruction (FEV1 as a percentage of forced vital capacity) compared with women who did not. These associations were not observed in men.
In East Anglia, the use of gas cooking is significantly associated with subjective and objective markers of respiratory morbidity in women but not in men. Women may be more susceptible than men to the products of gas combustion or they may have greater exposure to high concentrations of these products because they cook more frequently than men.
Environmental exposure to tobacco smoke and contaminants from unvented cooking stoves has been linked to impaired pulmonary function and respiratory diseases. These risk factors exist to a greater extent in developing countries and, in the case of exposure to tobacco smoke, they are reported to be increasing. In this study, pulmonary function studies were performed on 1905 children in Jordan. The effect of exposure to these environmental factors on respiratory function was analyzed. A significant negative impact was found with regard to environmental exposure to both passive smoking and wood and kerosene unvented cooking stoves. The mean values of lung function in children exposed and not exposed to passive smoking were, respectively, FVC (L): 1.29-1.49; FEV1 (L): 1.2-1.4; FEF25-75 (L/S): 1.84-2.24; PEFR (L/S): 2.6-3.21, and to wood and kerosene were FVC (L): 1.02-1.32; FEV1 (L): 0.91-1.25; FEF25-75 (L/S): 1.24-1.86; PEFR (L/S): 1.67-2.64. This is a major problem in developing countries because of the increasing incidence of smoking and the high exposure to pollution risk factors.
The association between exposure to air pollution from cooking fuels and health aspects was studied in Maputo. Mozambique. Almost 1200 randomly selected women residing in the suburbs of Maputo were interviewed and 218 were monitored for air pollution. The fuels most commonly used were wood, charcoal, electricity, and liquified petroleum gas (LPG). Wood users were exposed to significantly higher levels of particulate pollution during cooking time (1200 micrograms/m3) than charcoal users (540 micrograms/m3) and users of modern fuels (LPG and electricity) (200-380 micrograms/m3). Wood users were found to have significantly more cough symptoms than other groups. This association remained significant when controlling for a large number of environmental variables. There was no difference in cough symptoms between charcoal users and users of modern fuels. Other respiratory symptoms such as dyspnea, wheezing, and inhalation and exhalation difficulties were not associated with wood use. Reducing wood use would likely improve acute respiratory health effects in wood users and possibly improve the ambient air pollution conditions in Maputo. To reduce the health impact of wood smoke exposure, it appears that the least costly and quickest method would be to encourage charcoal use to a greater extent, although high carbon monoxide levels would have to be addressed. Turning to modern fuels is beyond the means of most these households in the short term and could not be shown to be more effective.
To study the association between ambient air pollutants (AAP) and respiratory symptoms complex (RSC) in preschool children, a cohort of 664 children between the ages of 1 month to 4.5 yr were randomly selected from 28 slums (anganwadi centres) of Lucknow, north India. They were followed up fortnightly for six months. The outcomes assessed were presence of RSC at the time of interview and days on which symptoms had occurred in the past week. Exposure to ambient air sulphur dioxide (SO2), oxides of nitrogen (NOx) and suspended particulate matter (SPM) on the day of the interview or in the week prior, was assessed by ambient air monitoring at 9 centres within the city. The cumulative incidence of RSC was 1.06 and the incidence density per 100 days of follow up was 1.63. All three pollutants were positively correlated with each other and negatively correlated with temperature. Ambient air SPM and SO2 and cooking and heating fuels like dung cakes, wood, coal and kerosene and remaining indoors while the food was cooked were associated with increased incidence of RSC, increased duration of symptoms, or both. We conclude that to improve the respiratory health of preschool children, ambient air SPM and SO2 levels should be kept as low as possible and mothers should be advised to keep children in another room while cooking.
We studied 269 school children from three Southern California communities of contrasting air quality in two successive school years, to investigate short-term effects of ambient ozone (O3), nitrogen dioxide (NO2), or particulate matter (PM) on respiratory health. We measured lung function and symptoms twice daily for one week each in fall, winter and spring; and concurrently assessed time-activity patterns and personal exposures. Average daily personal exposures correlated with pollutant concentrations at central sites (r = 0.61 for O3, 0.63 for NO2, 0.48 for PM). Questionnaire-reported outdoor activity increased slightly in communities/seasons with higher pollution. Lung function differences between communities were explainable by age differences. Morning forced vital capacity (FVC) decreased significantly with increase in PM or NO2 measured over the preceding 24 hours. Morning-to-afternoon change of forced expired volume in one second (FEV1) became significantly more negative with increase in PM, NO2, or O3 on the same day. Predicted FVC or FEV1 loss on highest- vs lowest-pollution days was < 2%. Daily symptoms showed no association with current or prior 24-hour pollution, but increased with decreasing temperature. Parents' questionnaire responses suggested excess asthma and allergy in children from one polluted community while children in the other polluted community reported more symptoms, relative to the cleaner community. We conclude that Los Angeles area children may experience slight lung function changes in association with day-to-day air quality changes, reasonably similar to responses seen by others in less polluted areas. Although short-term pollution effects appear small, they should be assessed in longitudinal lung function studies when possible, to allow maximally accurate measurement of longer-term function changes.
In the early summer of 1995, the acute respiratory effects of ambient air pollution were studied in a panel of 61 children, ages 7 to 13 yr, of whom 77% were taking asthma medication. Peak flow was measured twice daily with MiniWright meters at home and the occurrence of acute respiratory symptoms and medication use was registered daily by the parents in a diary. Exposure to air pollution was characterized by the ambient concentrations of ozone, PM10, and black smoke. During the study period, maximal 1-h ozone concentrations never exceeded 130 microg/m3, and 24-h black smoke and PM10 concentrations were never higher than 41 and 60 microg/m3 respectively. Associations of air pollution and health outcomes were evaluated using time series analysis. After adjusting for pollen, time trend, and day of the week, black smoke in particular was associated with acute respiratory symptoms and with medication use. Less strong associations were found for PM10 and ozone. These results suggest that in this panel of children, most of whom had asthma, relatively low levels of particulate matter and ozone in ambient air are able to increase symptoms and medication use.
It has been suggested that ultrafine particles in urban air may cause the health effects associated with thoracic particles (PM10). We therefore compared the effects of daily variations in particles of different sizes on peak expiratory flow (PEF) during a 57-day follow-up of 39 asthmatic children aged 7-12 years. The main source of particulate air pollution in the area was traffic. In addition to the measurements of PM10 and black smoke (BS) concentrations, an electric aerosol spectrometer was used to measure particle number concentrations in six size classes ranging from 0.01 to 10.0 microns. Daily variations in BS and particle number concentrations in size ranges between 0.032 and 0.32 micron and between 1.0 and 10.0 microns were highly intercorrelated (correlation coefficients about 0.9). Correlations with PM10 were somewhat lower (below 0.7). All these pollutants tended also to be associated with declines in morning PEF. However, the only statistically significant associations were observed with PM10 and BS. Different time lags of PM10 were also most consistently associated with declines in PEF. Therefore, in the present study on asthmatic children, the concentration of ultrafine particles was no more strongly associated with variations in PEF than PM10 or BS, as has earlier been suggested.
Although increases in inhalable particle (PM10) concentrations have been associated with acute reductions in the level of lung function and increased symptom reporting in children, including children with asthma, it is not clear whether these effects occur largely in asthmatic children, or even whether asthmatic children are more likely to experience these effects than children without asthma. To address these points, the following subgroups of children were selected from a survey population of all 2,200 elementary school children (6 to 13 yr of age) in a pulp mill community on the west coast of Vancouver Island: (1) all children with physician-diagnosed asthma (n = 75 participated), (2) all children with an exercise-induced fall in FEV1 without diagnosed asthma (n = 57), (3) all children with airway obstruction (FEV1/FVC < 0.76) without either of the above (n = 18), and (4) control children without any of the above (n = 56). The children were followed for as long as 18 mo with twice daily measurements of peak expiratory flow (PEF) and daily symptom diary recording. Maximum daily PM10 concentration was 159 microm/m3 (median, 22.1), but only 8 d (1.2%) had concentrations above 100 microg/m3. In an analysis that accounted for time-varying covariates, and serially correlated and missing data, for the entire sample of children, increases in PM10 were associated with reductions in PEF and increased reporting of cough, phlegm production, and sore throat. For the subgroup of children with diagnosed asthma, PEF in the time period with the highest PM10 concentrations fell by an estimated 0.55 L/min (95% CI, 0.06 to 1.05) for a 10 microg/m3 PM10 increase above the mean daily PM10 concentration of 27.3 microg/m3 and the odds of reported cough increased by 8% (95% CI, 0 to 16%); no consistent effects were observed in the other groups of children. It is concluded that children experience reductions in PEF and increased symptoms after increases in relatively low ambient PM10 concentrations, and that children with diagnosed asthma are more susceptible to these effects than are other children.
Pulmonary function studies were carried out in 3318 healthy, nonsmoking asymptomatic housewives to evaluate the role of different cooking fuels in domestic use. The women used four different types of cooking fuels: biomass fuel, liquified petroleum gas (LPG), kerosene used in stoves, and a combination of two or more of these (mixed). Four parameters of ventilatory function (FVC, FEV1, PEFR and MMEF) were evaluated. A positive correlation was observed between all these parameters except PEFR with that of height, but a negative correlation was observed between the age, duration of cooking and exposure index. Mixed fuels and biomass fuels affected FVC values (F = 6.39, p = 0.0003) more adversely. Similar trend was observed for FEV1 also. Users of biomass fuel had the lowest mean value for PEFR. Small airways function represented by MMEF was the lowest in users of kerosene. In users of mixed fuels, there was a decline in FVC, FEV1 and PEFR, as the exposure increased. Thus, it is concluded that, mixed fuel has more deleterious effects on pulmonary function than other fuels.
Nitrogen dioxide levels were measured in 80 homes in the Latrobe Valley, Victoria, Australia, using passive samplers. Some 148 children between 7 and 14 yr of age were recruited as study participants, 53 of whom had asthma. Health outcomes for the children were studied using a respiratory questionnaire, skin prick tests, and peak flow measurements. Nitrogen dioxide concentrations were low, with an indoor median of 11.6 microgram/m3 (6.0 ppb), and a maximum of 246 microgram/m3 (128 ppb). Respiratory symptoms were more common in children exposed to a gas stove (odds ratio 2.3 [95% CI 1. 0-5.2], adjusted for parental allergy, parental asthma, and sex). Nitrogen dioxide exposure was a marginal risk factor for respiratory symptoms, with a dose-response association present (p = 0.09). Gas stove exposure was a significant risk factor for respiratory symptoms even after adjusting for nitrogen dioxide levels (odds ratio 2.2 [1.0-4.8]), suggesting an additional risk apart from the average nitrogen dioxide exposure associated with gas stove use. Atopic children tended to have a greater risk of respiratory symptoms compared with nonatopic children with exposure to gas stoves or nitrogen dioxide, but the difference was not significant.
A study was carried out in 200 school children from north India to find out the effects of passive smoking and exposure to domestic cooking fuels on their lung functions. Forced vital capacity and FEV1 were the lowest in boys whose households used biomass fuel (p < 0.05) and PEFR and FEF 25% and 50% were lowest in boys with their homes using kerosene as fuels. All these were the best for LPG fuel. However, in girls there was no significant difference in different parameters, although the values were lower in those using kerosene and biomass fuel. All parameters were lower in passive smokers irrespective of the type of fuel used although they were not statistically significant. However, FEF 50% was significantly less in passive smokers whose households used mixed fuels. The same was true for PEFR, PEFR %, and FEF 25% in cases of LPG fuel use.
A relation between water hardness and cardiovascular death has been shown in previous studies. In this case-control study, we investigated the levels of magnesium and calcium in drinking water and death from acute myocardial infarction among women. The study population encompassed 16 municipalities in southern Sweden. Cases were women who had died from acute myocardial infarction between the ages of 50 and 69 years during 1982-1993 (N = 378), and controls were women who had died from cancer (N = 1,368). We obtained magnesium and calcium concentrations of the individual water sources. We divided the subjects into quartiles and found that odds ratios (ORs) were lower at higher levels of both magnesium and calcium. For the quartile with the highest magnesium levels (> or =9.9 mg/liter), the OR adjusted for age and calcium was 0.70 (95% confidence interval = 0.50-0.99). For calcium, the adjusted OR for the quartile with the highest level (> or =70 mg/liter) was 0.66 (95% confidence interval = 0.47-0.94). The results suggest that magnesium and calcium in drinking water are important protective factors for death from acute myocardial infarction among women.
Twenty-four-hour samples of PM10 (mass of particles with aerodynamic diameter < or = 10 microm), PM2.5, (mass of particles with aerodynamic diameter < or = 2.5 microm), particle strong acidity (H+), sulfate (SO42-), nitrate (NO3-), ammonia (NH3), nitrous acid (HONO), and sulfur dioxide were collected inside and outside of 281 homes during winter and summer periods. Measurements were also conducted during summer periods at a regional site. A total of 58 homes of nonsmokers were sampled during the summer periods and 223 homes were sampled during the winter periods. Seventy-four of the homes sampled during the winter reported the use of a kerosene heater. All homes sampled in the summer were located in southwest Virginia. All but 20 homes sampled in the winter were also located in southwest Virginia; the remainder of the homes were located in Connecticut. For homes without tobacco combustion, the regional air monitoring site (Vinton, VA) appeared to provide a reasonable estimate of concentrations of PM2.5 and SO42- during summer months outside and inside homes within the region, even when a substantial number of the homes used air conditioning. Average indoor/outdoor ratios for PM2.5 and SO42- during the summer period were 1.03 +/- 0.71 and 0.74 +/- 0.53, respectively. The indoor/outdoor mean ratio for sulfate suggests that on average approximately 75% of the fine aerosol indoors during the summer is associated with outdoor sources. Kerosene heater use during the winter months, in the absence of tobacco combustion, results in substantial increases in indoor concentrations of PM2.5, SO42-, and possibly H+, as compared to homes without kerosene heaters. During their use, we estimated that kerosene heaters added, on average, approximately 40 microg/m3 of PM2.5 and 15 microg/m3 of SO42- to background residential levels of 18 and 2 microg/m3, respectively. Results from using sulfuric acid-doped Teflon (E.I. Du Pont de Nemours & Co., Wilmington, DE) filters in homes with kerosene heaters suggest that acid particle concentrations may be substantially higher than those measured because of acid neutralization by ammonia. During the summer and winter periods indoor concentrations of ammonia are an order of magnitude higher indoors than outdoors and appear to result in lower indoor acid particle concentrations. Nitrous acid levels are higher indoors than outdoors during both winter and summer and are substantially higher in homes with unvented combustion sources.
This investigation reports the association between air pollution and paediatric respiratory emergency visits in São Paulo, Brazil, the largest city in South America. Daily records of emergency visits were obtained from the Children's Institute of the University of São Paulo for the period from May 1991 to April 1993. Visits were classified as respiratory and non-respiratory causes. Respiratory visits were further divided into three categories: upper respiratory illness, lower respiratory illness and wheezing. Daily records of SO2, CO, particulate matter (PM10), O3 and NO2 concentrations were obtained from the State Air Pollution Controlling Agency of São Paulo. Associations between respiratory emergency visits and air pollution were assessed by simple comparative statistics, simple correlation analysis and by estimating a variety of regression models. Significant associations between the increase of respiratory emergency visits and air pollution were observed. The most robust associations were observed with PM10, and to a lesser extent with O3. These associations were stable across different model specifications and several controlling variables. A significant increase in the counts of respiratory emergency visits--more than 20%--was observed on the most polluted days, indicating that air pollution is a substantial paediatric health concern in São Paulo.
Area 22-h average carbon monoxide (CO), total suspended particulates (TSP), particles less than 10 microns in diameter (PM10), and particles less than 2.5 microns in diameter (PM2.5) measurements were made in three test homes of highland rural Guatemala in kitchens, bedrooms, and outdoors on a longitudinal basis, i.e. before and after introduction of potential exposure-reducing interventions. Four cookstove conditions were studied sequentially: background (no stove in use); traditional open woodstove, improved woodstove with flue (plancha), and bottled-gas (LPG) stove. With nine observations each, kitchen PM2.5 levels were 56 micrograms/m3 under background conditions, 528 micrograms/m3 for open fire conditions, 96 micrograms/m3 for plancha conditions, and 57 micrograms/m3 for gas stove conditions. Corresponding PM10/TSP levels were 173/174, 717/836, 210/276, 186/218 micrograms/m3. Corresponding CO levels were 0.2, 5.9, 1.4, 1.2 ppm. Comparisons with other studies in the area indicate that the reductions in indoor concentrations achieved by improved wood-burning stoves deteriorate with stove age. Mother and child personal CO and PM2.5 measurements for each stove condition demonstrate the same trend as area measurements, but with less differentiation.