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Air Pollution and Health in Urban Areas
Abstract
In this paper, recent reviews of the World Health Organization, other review papers, and more recent literature on the human health effects of current air pollution trends in urban areas are reviewed and summarized as follows: Sulphur dioxide. Some studies, but not others, found associations between sulphur dioxide (SO2) exposure and daily mortality and morbidity. Single-pollutant correlations sometimes disappeared when other pollutants, especially suspended particulate matter (SPM), were included. Cross-sectional studies with asthmatics revealed significant, non-threshold relations between SO2 and decrements of the forced expiratory volume in 1 second (FEV1). Nitrogen dioxide. Weak associations between short-term nitrogen dioxide (NO2) exposure from gas cooking and respiratory symptoms and a decrement in lung function parameters were found in children, but not consistently in exposed women. With long-term exposure, children, but not adults, exhibit increased respiratory symptoms, decreased lung function, and increased incidences of chronic cough, bronchitis, and conjunctivitis. A causal relationship between NO2 exposure and adverse health effects has not yet been established. Carbon monoxide. Binding of CO in the lungs with hemoglobin in the blood forms carboxyhemoglobin (COHb), which impairs the transport of oxygen. The health effects of CO include hypoxia, neurological deficits and neurobehavioral changes, and increases in daily mortality and hospital admissions for cardiovascular diseases. The latter persists even at very low CO levels, indicating no threshold for the onset of these effects. Whether the relation between daily mortality and exposure to CO are causal or whether CO might act as a proxy for SPM is still an open question. Ambient CO may have even more serious health consequences than does COHb formation and at lower levels than that mediated through elevated COHb levels. Ozone. Short-term acute effects of O3 include pulmonary function decrements, increased airway responsiveness and airway inflammation, aggravation of pre-existing respiratory diseases like asthma, increases in daily hospital admissions and emergency department visits for respiratory causes, and excess mortality. Exposure-response relations are non-linear for the respective associations between O3 and FEV1, inflammatory changes, and changes in hospital admissions, whereas the relation between percent change in symptom exacerbation among adults and asthmatics is linear. Single-pollutant associations between O3 exposure and daily mortality and hospital admissions for respiratory diseases is statistically significant, even in multi-pollutant models. Suspended particulate matter. Associations between SPM concentrations and mortality and morbidity rates are significant. The acute health effects of SPM, even at short-term low levels of exposure, include increased daily mortality and hospital admission rates for exacerbation of respiratory disease, fluctuations in the prevalence of bronchodilator use, and cough and peak flow reductions, as well as long-term effects with respect to mortality and respiratory morbidity. Such effects depend on particle size and concentration and can fluctuate with daily fluctuations in PM10 or PM2.5 levels. The relation between PM10 or PM2.5 exposure and acute health effects is linear at concentrations below 100 micrograms/m3. Currently no threshold has been reported below which no effects occur. The influence of co-polluting gaseous pollutants could explain part of the observed variance in short-term health effects and reduce the contribution of SPM. Lead. The biological effects of lead can be related to blood lead levels, the best indicator of internal exposure. The potential effects of lead in adults and children include encephalopathic signs and symptoms, central nervous system symptoms, cognitive effects, increased blood pressure, and reduced measures of child intelligence. (ABSTRACT TRUNCATED)
... The coarse dust particles (PM 10 ) mainly affect the upper respiratory system, while the finer particles (PM 2.5 ) can penetrate the lung barrier and enter the blood system, causing heart attacks, strokes, asthma and bronchitis, as well as premature death from cancer. Research also shows that the longer exposure to high concentrations of PM 2.5 can impair brain development in children and have reproductive effects, such as infant mortality and low birth weight (Gao et al. 2014, Schwela 2000, Health Effects Institute 2020, Manisalidis et al. 2020. Also important is the fact that the particles can have toxic effects according to their chemical compounds, primarily metals (Cheung et al. 2011). ...
... Breathing air with high levels of them may cause the development of asthma and bronchitis and even pulmonary oedema. They may also lead to an increased risk of heart disease (Schwela 2000, Chen et al 2007, Gao et al. 2014, Manisalidis et al. 2020. The main health problems associated with sulphur dioxide (SO 2 ), apart from respiratory irritation, bronchitis, and the fact that it exacerbates asthma, are skin redness, eye irritation and cardiovascular disease (Chen et al. 2007). ...
... Finally, it could lead to loss of consciousness. Due to the loss of oxygen, hypoxia, neurological deficits and neurobehavioral changes as well as ischemia, and cardiovascular disease are observed (Schwela 2000, Manisalidis et al. 2020. ...
Rapid socio-economic development and urbanization have contributed to the serious deterioration of air quality in many world cities including Pristina, the capital of Kosovo. Through a data-driven analysis of regulatory intervention, this study attempts to examine the effectiveness of air pollution control regulations that have been implemented in Kosovo between 2010–2021. Our results show that the measures enforced during this 10-year period in Kosovo, and particularly in the capital city, have resulted in the reduction of pollution. The applied methods for this research are the standard ones of the Instituti Hidrometeorologjik i Kosovës (Hydrometeorological Institute of Kosovo). All results showed a decrease of each pollutant over the ten years. These changes strongly indicated that the origin of the pollution was traffic and anthropogenic activity, while the power plant was considered to be a less significant source of pollution. The basic pollutants of air quality in Pristina are particulate matter (PM2.5 and PM10), ozone and nitrogen oxide.
... Air pollutants such as NO x, are found to be highly associated with ocular diseases such as conjunctivitis (Bourcier et al., 2003). The pollutants are reported to alter the lacrimal pH, causing irritation and inflammation of the eyes (Dietrich Schwela, 2000). The acute and chronic exposures to indoor air pollution may consequently result in eye irritation and sometimes loss of eyesight. ...
... The huge vehicular traffic exposure in urbanized Terai and Hilly areas has caused difficulties with vision (Bourcier et al., 2003;Dhakal et al., 2017;Dietrich Schwela, 2000;Patel et al., 2022;Paudel et al., 2017;Versura et al., 1999). A recent study on ophthalmic discomfort experienced by citizens of heavily trafficked Kathmandu valley reported that 80% of the pedestrians suffered from Ocular Surface Diseases (OSD) while 38% reported severe symptoms and 17% the abnormal tear secretion problems (Paudel et al., 2017). ...
According to a recent survey, Nepal's urban air quality has been classified as one of the worst in the globe. A large portion of the country's population is subjected to health risks caused by air pollution. As Nepal has a wide variation in altitude coupled with socio-cultural and biological diversities, it is important to understand the different health hazards in the different geographical regions - Terai, Hills and Mountains. Constantly increasing physical infrastructures (such as transport vehicles and open burning of plastics and other fuels) are the main reasons for the escalating air pollution in the country. This study aims at critically reviewing the current air pollution status in different geographical locations along with its impacts on public health in the country. It has been revealed that irrespective of geographical locations, the air pollutants interfere with different human physiological systems related to respiration as well as cardiovascular, ophthalmic and gastrointestinal functioning. Further, the research findings highlighting the influence of prolonged exposure of the population to the air pollution leading to significant number of deaths have been presented. A notable rise in number of hospitalized patients suffering from illnesses related to above mentioned pollution born cases has been reported.
... 5 Urbanized areas have a higher risk of increased air pollution concentrations largely due to energy consumption and exhaust emissions. 6,7,8 Therefore, the urban areas have a higher risk of various cardiovascular diseases (CVDs). 4 The World Health Organization (WHO) has stated about 80% of people living in cities are breathing in air that is over the WHO guideline limit. ...
... 4 The World Health Organization (WHO) has stated about 80% of people living in cities are breathing in air that is over the WHO guideline limit. 6 Specifically, people from lower and middle-income countries suffer from the most exposure and, therefore, are at the highest risk of air pollution-related health risk. 7 Within the U.S., 80.2% of Americans live in an urban area versus the 19.8% that live in a rural area. ...
The effect of air pollution on health is listed as a significant cause of death worldwide. Slightly over 3 million deaths per year are due to outdoor air pollution. Studies have shown that short term increases in exposure to particulate matter have increased the risk of cardiovascular diseases such as myocardial infarction, stroke, and heart failure. However, less is known about the longer term effects of air pollution on various cardiovascular diseases. The American Heart Association formally recognized PM2.5 as a significant cardiovascular risk factor in 2010. Since then, more prolonged term exposure to air pollution has been suggested to cause chronic cardiometabolic and cardiovascular problems. The effects of long term (>3 years) air pollution are significant, but not as much is known about how location affects this exposure. Associations with cardiovascular diseases and their risk factors are often increased in urban settings, which is attributed to a higher concentrations of outdoor air pollution, independent of ethnic groups and seasonal changes. Potential causes of long term air pollution concentrations in cities or metropolitan areas come from traffic exposure and traffic intensity. The Environmental Protection Agency and United Nations have suggested changes in air quality standards, implementation plans, and ways to reduce vehicle emissions specifically to improve human health and reduce the adverse effects of air pollution; however, more work still needs to be done. This review assesses the impact of the global long term (>3 years) air pollution exposure, specifically in urban environments on cardiovascular health and disease.
... The level of road-side pollution in Kano is reportedly beyond the WHO recommended safe limits of 20 µg/m 3 (Efe, 2008;Okunola et al., 2012),revealing that transport-related pollution in Kano metropolis can be potentially hazardous to health. Equally, significant cardiopulmonary morbidity and higher prevalence of respiratory symptoms have been implicated in roadside pollution (Schwela, 2000;Nku et al., 2005;Jones et al., 2008). This is especially worrisome considering the fact that risk of mortality increases by approximately 15 to 25% in cities with higher pollution levels (Efe, 2008). ...
... This finding corroborates well with earlier reports by Chilcott (2007), Adeniyi et al. (2014) and Chauhan et al. (2014) among individuals exposed to petroleum fumes. It is also in tandem with findings of Schwela (2000), Nku et al. (2005), Efe (2008), Jones et al. (2008) and Ibrahim (2014) among individuals who are exposed to ambient roadside pollution. LIMITATIONS Air analysis and the analysis of metabolites were not done, hence they could not be commented upon. ...
Background: Petroleum hawkers are exposed to both ambient road-side pollutants and
petroleum fumes which have both been reported to cause significant pulmonary
impairment and respiratory symptoms. Despite their comorbid exposure, there is paucity
of knowledge regarding the effects of road-side petroleum hawking on respiratory
functions. Aim: The aim of this study is to assess lung function and respiratory symptoms
of roadside petroleum hawkers in Kano. Methods: A total of 49 roadside petrol hawkers,
50 roadside traders and 54 non-roadside traders participated in the study. Spirometry was
used to assess forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1),
Tiffeneau-Pinelli index (FEV1/FVC) and peak expiratory flow (PEF) while a modified
version of medical research council’s questionnaire was used to assess respiratory
symptoms among the respondents. One-way ANOVA was used to compare means using
SPSS version 20.0. Results: The results showed a statistically significant decrease in
FVC, FEV1 and PEF among the petrol hawkers as compared to the roadside traders and
non-roadside traders, respectively. Although, the Tiffeneau-Pinelli indices of petrol
hawkers differ much significantly from that of the non- roadside traders, it did not show
significant decrease when compared with that of the roadside traders, signifying a
restrictive form of air way affectation. This pattern was found to associate independently
well, with both the duration and the intensity of their exposure. It was also found that
petrol hawkers exhibit significantly higher prevalence of occupation related cough, eye
irritation, irritated and/or runny nose relative to non-roadside traders. Conclusion: Our
finding suggests that exposure to petroleum was associated with a restrictive form of
airway affectation while the combined effects of road-side pollution and petroleum
exposure may predispose roadside petroleum hawkers to a mixed type of air way diseases
and a significantly higher prevalence of respiratory symptoms.
... Long-term exposure to particulate matter <10 mm in diameter had a significant negative effect on lung-function proxy for the development of large (forced expiratory volume in one second) and small (mid-expiratory flow between 25 and 75% of the forced vital capacity) airways, respectively (Horak et al., 2002). Particulates are especially dangerous because they have been implicated in the development of lung cancer and higher rates of mortality (Schwela, 2000). ...
One of the characteristics of petroleum industry in developing countries is incessant flare of gases with its attendant socio-ecological impacts. Gas flaring has not only contributed to poor environmental quality and pollution but play remarkable role in micro-climate modification. The aim of this study was to examine the effects of gas flaring on air quality of Ologbo flow station, Edo state. Data was collected for air within defined distances from the flaring point in accordance with standard procedure. A 4 km distance from the flare facility was buffered. Sampling sites 1, 2, and 3 are within the vicinity of the flare facility, while the control point (Evbuarhue) is located 30 km from the fence of the flare facility. Air Quality measurements were done for carbon monoxide (CO), nitrogen dioxide (NO2), methane CH4 and ammonia (NH3) using toxic gas monitors meter; toxic EEX 79 IICT3-T4 and CE89/336/EEC. The Ambient Air Quality and humidity were analyzed in situ using the standards adopted by the Federal Ministry of Environment. Temperature was discovered to have risen by 10 0 C at station 1. Relative humidity was recorded as 63%. Average total suspended particulates, nitrogen dioxide, carbon monoxide, sulphur dioxide ammonia and methane were recorded as 2.25, 1.2, 3.0, 0.014, 0.01 and 0.01 ppm, respectively. These values exceeded results obtained at control site. Standard deviation varied from 1.35 for temperature, 7.8 for relative humidity, 1.19 for total suspended particulates, 0.84 for nitrogen dioxide, 1.87 for carbon monoxide, 0.007 for sulphur dioxide and 0.00 for ammonia and methane. With continuous flare of gas, the study area will over time undergo further alterations in its air quality.
... On any day or location, the PM mass concentration may be similar, yet the composition may vary greatly enough to differentially impact human health (Brook et al., 2003). The relationship between PM 10 or PM 2.5 exposure and acute health effects is linear at concentrations below 100 μg/m 3 (Schwela, 2000). A modest rise in PM 10 or PM 2.5 level has been shown to be associated with small changes in cardiac function. ...
... World Health Organization estimates that around 7 million premature death happens every year caused by exposure to polluted air, due to exposure to highly polluted air by 9 out of 10 people all over the World (WHO, 2018). Epidemiological and toxicological studies show a link between urban air pollutants that can induce airway inflammation and airway hyperresponsiveness and the increasing rate and/or severity of respiratory and cardiovascular diseases (Koren, 1995;Madureira et al., 2019;Schwela, 2000;Zoran et al., 2020). ...
Different health management strategies may need to be implemented in different regions to cope with diseases. The current work aims to evaluate the relationship between air quality parameters and the number of new COVID-19 cases in two different geographical locations, namely Western Anatolia and Western Black Sea in Turkey. Principal component analysis (PCA) and regression model were utilized to describe the effect of environmental parameters (air quality and meteorological parameters) on the number of new COVID-19 cases. A big difference in the mean values for all air quality parameters has appeared between the two areas. Two regression models were developed and showed a significant relationship between the number of new cases and the selected environmental parameters. The results showed that wind speed, SO2, CO, NOX, and O3 are not influential variable and does not affect the number of new cases of COVID-19 in the Western Black Sea area, while only wind speed, SO2, CO, NOX, and O3 are influential parameters on the number of new cases in Western Anatolia. Although the environmental parameters behave differently in each region, these results revealed that the relationship between the air quality parameters and the number of new cases is significant.
... Furthermore, Calderón-Garcidueñas et al. (2015) warned of the inflammatory effect of PM 10 and O 3 concentrations on the central nervous system in clinically healthy children living in the MCMA. Different studies on human health outcomes in other polluted locations have also found that ozone plays an important role as an inflammatory factor in airway diseases (Hiltermann et al.,1998, Schwela, 2000, Alexis et al., 2010, Oakes et al., 2013. Several studies have also shown a positive relationship between ozone concentration and levels of stress hormones in humans (Miller et al., 2016, Rajagopalan and Brook, 2016, Wang et al., 2022, Xia et al., 2022. ...
Mexico City is one of the most polluted cities in the world, and one in which air contamination is considered a public health threat. Numerous studies have related high concentrations of particulate matter and ozone to several respiratory and cardiovascular diseases and a higher human mortality risk. However, almost all of those studies have focused on human health outcomes, and the effects of anthropogenic air pollution on wildlife species is still poorly understood. In this study, we investigated the impacts of air pollution in the Mexico City Metropolitan Area (MCMA) on house sparrows (Passer domesticus). We assessed two physiological responses commonly used as biomarkers: stress response (the corticosterone concentration in feathers), and constitutive innate immune response (the concentration of both natural antibodies and lytic complement proteins), which are non-invasive techniques. We found a negative relationship between the ozone concentration and the natural antibodies response (p = 0.003). However, no relationship was found between the ozone concentration and the stress response or the complement system activity (p > 0.05). These results suggest that ozone concentrations in air pollution within MCMA may constrain the natural antibody response in the immune system of house sparrows. Our study shows, for the first time, the potential impact of ozone pollution on a wild species in the MCMA presenting the Nabs activity and the house sparrow as suitable indicators to assess the effect of air contamination on the songbirds.
... Even at ppm levels, these gases gas can cause severe damage to the respiratory and cardiovascular systems. [4][5][6][7] In particular, nitrogen dioxide (NO 2 ) is a greenhouse gas and a significant contributor to global deaths resulting from inadequate air quality management. 8 However, these hazardous gases are critical precursors and/or byproducts in chemicals, petroleum, medicine, agriculture, and energy applications that require effective environmental management. ...
Various non-stratified two-dimensional (2D) materials can be obtained from liquid metal surfaces that are not naturally accessible. Homogenous nucleation on atomically flat interfaces of liquid metals with air produces unprecedented high-quality oxide layers that can be transferred onto desired substrates. The atomically flat and large areas provide large surface-to-volume ratios ideal for sensing applications. Versatile crucial applications of the liquid metal-derived 2D oxides have been realized; however, their gas-sensing properties remain largely underexplored. The cubic In2O3 structure, which is nonlayered, can be formed as an ultrathin layer on the surface of liquid indium during the self-limiting Cabrera-Mott oxidation process in the air. The morphology, crystal structure, and band structure of the harvested 2D In2O3 nanosheets from liquid indium are characterized. Sensing capability toward several gases, both inorganic and organic, entailing NO2, O2, NH3, H2, H2S, CO, and Methyl ethyl ketone (MEK) are explored. A high ohmic resistance change of 1974% at 10 ppm, fast response, and recovery times are observed for NO2 at an optimum temperature of 200 °C. The sensing fundamentals are investigated for NO2, and its performances and cross-selectivity to different gases are analyzed. The NO2 sensing response from room temperature to 300 °C has been measured and discussed, and stability after 24 hours of continuous operation is presented. The results demonstrate liquid metal-derived 2D oxides as promising materials for gas sensing applications.
... The adverse health effects associated with the high concentration of these pollutants are great. NOx is responsible for immune system impartment, exacerbation of asthma and chronic respiratory diseases, reduced lung function and cardiovascular disease (Schwela, 2000); while CO reduces oxygen flow in blood stream, exacerbates coronary heart diseases, and at low concentrations can impair concentration and neuro-behavioural function (Udeozor and Nzeakor, 2012). ...
... According to the Environmental Protection Agency (USEPA, 2007). Schwela, (2000), concluded that many studies have confirmed adverse health effects associated with high concentrations of transport-related pollutants. ...
... In industrialized countries with highly dense populations, large towns can suffer from air and soil pollution derived from human activities. Air can be polluted by indoor combustion of firewood, biomass fuels for heating, daily cooking at home or restaurants, and industrial activities that can generate high concentrations of particulate matter, sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), and ozone in urban areas [8]. ...
Urban areas can be differently anthropized; often, high-density populations lead to higher amounts of pollution. Nowadays, ornamental plants can represent important living components of urban areas, and if appropriate species are used, they can provide important ecosystem services. The relationships between green infrastructures and ecosystem services have been recognized for a long time, but the role of ornamental plant species has not been studied as much. In this frame, the different ecosystem services of ornamental plants, i.e., provisioning (e.g., food, air, and water cleaning), regulating (e.g., rain water, climate, nutrient recycling, pollination, and the formation of fertile soils), and cultural (e.g., recreation opportunities or the inspiration we draw from nature) will be critically analyzed to select the most suitable ornamental plant species able to assure the better performance. The action mechanisms will also be analyzed and discussed to individuate the best ideotypes of plant species able to better assure water purification, air quality, space for recreation, climate mitigation and adaptation, human wellbeing, and health. This information is suitable to ensure that the protection, restoration, creation, and enhancement of green infrastructure become integral parts of urban spatial planning and territorial development.
... Darçın (2014) found that air pollution harmed people's quality of life. Several researchers have also reported that the harmful effect of air pollution on mental health results in poor judgement, inhibits people's capacity to absorb information, and increases information asymmetry in subsequent results (Ackert et al. 2003;Schwela 2000). ...
This study examined the effect of air pollution on the initial return of IPOs in Pakistan. Cross-sectional data were used to examine 102 listed IPOs on Pakistan Stock Exchange between 1996 and 2019. Ordinary least squares and quantile least squares were employed to examine the influence of air pollution on IPO initial returns. Lastly, stepwise regression was utilised for additional analysis. According to the findings, in the presence of high air pollution, IPO initial returns also increase due to higher uncertainty. The findings demonstrate that air pollution intensifies a company’s information environment and financial uncertainty. Therefore, addressing environmental challenges is critical for both public health and capital formation. This study’s findings will increase companies’ awareness of the economic effect of air pollution, particularly in a country where air pollution is strictly regulated. This study provides businesses with an economic reason to reduce their pollution levels, and it can also help regulators pass environmental laws that are aimed at addressing this issue.
... In the recent years, emerging air pollutants around the world and their impact on public health are the key area of study (19)(20)(21)(22). In few important aspects such as indoor and outdoor air quality, the WHO (23) reports that 3.8 million deaths are caused by higher risk of diseases, which generate through indoor air pollution. ...
In the recent years, public health has become a core issue addressed by researchers. However, because of our limited knowledge, studies mainly focus on the causes of public health issues. On the contrary, this study provides forecasts of public health issues using software engineering techniques and determinants of public health. Our empirical findings show significant impacts of carbon emission and health expenditure on public health. The results confirm that support vector machine (SVM) outperforms the forecasting of public health when compared to multiple linear regression (MLR) and artificial neural network (ANN) technique. The findings are valuable to policymakers in forecasting public health issues and taking preemptive actions to address the relevant health concerns.
... Wildfires result in the production of smoke, carbon dioxide (CO 2 ), and carbon monoxide (CO). Most forms of air pollution are because of human activities and they include fossil fuel burning (charcoal, oil, and natural gas as a source of heating), electricity generation, vehicle emissions, aircraft emissions, domestic fuel burning, and the use of household materials that contain persistent organic pollutants, biomass burning, and waste incineration [24]. ...
Indoor air quality is essential, so its quality cannot be compromised. Hence, this research assessed indoor gaseous air pollutant concentrations from sources in thirty-three residential kitchens within the 4-zone of Ilorin-South Local Government, Kwara, Nigeria. The work focused on SO2, NO2, and CO emission concentration quantification, determination of the air quality index (AQI), estimation of health assessment risk, and deduced their health implications on the residents. The concentrations of NO2 and SO2 were determined by the Saltzman method using a Gilair-3 air sampler, while the concentration of CO was determined using an MSA Altair-5x multigas detector. Three types of eleven kitchen environments each (kitchens where liquefied petroleum gas (LPG), charcoal, and firewood were used as fuel sources) were considered. The concentrations of NO2, SO2, and CO were higher in kitchens that used charcoal and firewood. The major health risks were deduced in percentages from the questionnaire administered, where headaches had the highest percentage (20.7). The model indicated that the concentrations of the pollutants in the evening, irrespective of the sampling points, were higher than those in the morning. Firewood contributed significantly more than charcoal and LPG ( p < 0.05 ). The results of the health assessment risk showed that the risk estimated for normal exposure to the pollutants in all the households studied revealed a hazard quotient of <1.0 except for SO2 from firewood for infants and children = 1.09. The AQI results showed the worst health conditions for households that used firewood (0.103–4.760 ppm NO2; 0.327–0.647 ppm SO2; and 12.30–57.83 ppm CO). The study concluded that the use of LPG should be preferred as a source of fuel for cooking.
... Anthropogenic activities has led to an enormous increase in the presence of toxic, flammable and exhaust gases that pose a great threat to the environmental sustainability [1]. Some of the toxic gases such as carbon monoxide (CO), sulphurous oxide (SO 2 ), carbon dioxide (CO 2 ), nitrous oxide (NO X ) are very harmful and their long-term exposure can cause various health effects such as asthma, respiratory disorders and other neurological effects. ...
The ability to monitor toxic gases under room-temperature conditions, with enhanced response and selectivity present in the atmosphere, is still considered as a technical challenge. In this context, we have fabricated AlGaN/GaN high electron mobility transistors (HEMTs) based sensors incorporating molybdenum disulfide (MoS2) functionalization for very sensitive, selective, and quick measurement of even trace amounts of hazardous NO2 gas in the ambient under room-temperature conditions. MoS2 structures with vertically aligned flower-like structure were synthesized using a simple hydrothermal technique and applied to the gate region of AlGaN/GaN HEMTs. The electrical characterizations of MoS2 functionalized AlGaN/GaN HEMTs are then used to detect the presence of NO2 gas. The fabricated sensor showed an enhanced relative sensing response in the range of 40.5 to 56.7% for 1–100 ppm NO2 gas with complete recovery to 1 ppm NO2 concentration under room-temperature conditions (25ᵒC) without applying any external thermal or optical stimuli. Furthermore, the cyclic and selectivity tests were performed and we found our sensor to be highly selective towards NO2 gas among various other gases. The experimental results showed that MoS2 had excellent properties for NO2 gas detection when used on such GaN-based sensing platform. These findings may be attributed to the exposed edge sites of MoS2 which compliment with configurations with sulphur and the chemisorption phenomenon on its surface that results in altering the drain to source current (IDS) of the HEMT at a constant drain to source voltage (VDS) of 0.5 V. These findings suggest that gas sensors based on the AlGaN/GaN HEMT structure appear to be a promising candidate for the advancement of application potentials of nitride-based integrated electronics.
... They can wash into streams or be ingested by animals from the soil. Poor air quality, for example, can have an impact on our climate; some pollutants contribute to warming while others contribute to cooling 31 . Poor air quality can have serious economic consequences due to its effects on human health and the environment. ...
Background: One of the major challenging environmental problems facing both the developed and developing countries of the world today is atmospheric pollution. This has been recently linked to increased morbidity and mortality rates. Industrial and Traffic-related vehicular emissions and non implementation of air quality standards in Nigeria are thought to have caused serious health problems, particularly in metropolitan areas where pollution levels are rising. However, due to lack of data on atmospheric pollution levels, collection of ambient air quality data in the research area has become important. This study therefore, seeks to determine the levels of some air quality parameters in the study area. Materials and Methods: Experimental research was employed and it enabled air quality data (VOCs, SO 2 , CO, H 2 S NH 3 , NO 2 , PM 10 and TSP) to be quantitatively gathered in the field using standard methods and handheld in-situ meters. Data obtained were analyzed and presented with tables, means, t-test, ANOVA and Pearson's correlation tools, using SPSS software version 23. Results: Result obtained from the study showed significant variation in the concentration level of air pollutants along the studied sites at p>0.05. There was also significant seasonal variation per site. In addition, Pearson's correlation revealed both positive and negative association between air pollutants across seasons per studied site, which shows that some of the air pollutants have common emission source which is associated with mostly vehicular emission. Conclusion: The study therefore recommend that more roads with connectivity should be constructed to link Calabar with Uyo in order to reduce the traffic density along the only transport corridor that links Calabar to other states; and recommends regular monitoring of atmospheric pollutants.
... The adverse effects of air pollutants such as CO, NOx, PM, and O 3 on human eyes consist of mostly irritation and inflammation, with conjunctivitis being a frequent problem [14]. Numerous studies have tried to determine the impact of environmental toxins on the ocular surface. ...
Air pollution is inevitably the result of human civilization, industrialization, and globalization. It is composed of a mixture of gases and particles at harmful levels. Particulate matter (PM), nitrogen oxides (NOx), and carbon dioxides (CO2) are mainly generated from vehicle emissions and fuel consumption and are the main materials causing outdoor air pollution. Exposure to polluted outdoor air has been proven to be harmful to human eyes. On the other hand, indoor air pollution from environmental tobacco smoking, heating, cooking, or poor indoor ventilation is also related to several eye diseases, including conjunctivitis, glaucoma, cataracts, and age-related macular degeneration (AMD). In the past 30 years, no updated review has provided an overview of the impact of air pollution on the eye. We reviewed reports on air pollution and eye diseases in the last three decades in the PubMed database, Medline databases, and Google Scholar and discussed the effect of various outdoor and indoor pollutants on human eyes.
... Air pollution is an urgent global health problem, and one that has gained additional attention during the coronavirus disease 2019 (COVID-19) pandemic due to the exacerbating effects of pollutant exposure on infectious disease spread and mortality (1)(2)(3). Two main air pollutants-fine particulate matter (PM 2.5 , defined as particulate matter with diameter of ≤2.5 m) and ground-level ozone (hereafter, "ozone")-are linked to significant human health concerns including cardiovascular and respiratory illnesses and mortality (4)(5)(6)(7). PM 2.5 and ozone have also been linked to negative ecosystem impacts via their detrimental effects on plants and the broader environment (8)(9)(10). Although few studies have quantified the compounding health impacts of co-occurring PM 2.5 and ozone, existing research indicates that simultaneous exposure to both pollutants can have disproportionately more severe health impacts beyond the individual effect of either pollutant (11,12). ...
Wildfires and meteorological conditions influence the co-occurrence of multiple harmful air pollutants including fine particulate matter (PM2.5) and ground-level ozone. We examine the spatiotemporal characteristics of PM2.5/ozone co-occurrences and associated population exposure in the western United States (US). The frequency, spatial extent, and temporal persistence of extreme PM2.5/ozone co-occurrences have increased significantly between 2001 and 2020, increasing annual population exposure to multiple harmful air pollutants by ~25 million person-days/year. Using a clustering methodology to characterize daily weather patterns, we identify significant increases in atmospheric ridging patterns conducive to widespread PM2.5/ozone co-occurrences and population exposure. We further link the spatial extent of co-occurrence to the extent of extreme heat and wildfires. Our results suggest an increasing potential for co-occurring air pollution episodes in the western US with continued climate change.
... By then, it is expected that Earth's urban corridors will have added 2.5 billion people and that 7 out of 10 people on this planet will live in a city. [1] Today, many livability hazards characteristic of urban population centers stem from poor planning and little consideration to scalability: crime [2], congestion [3], pollution [4], and inequity in access to services [5] are common features of urban life and without careful consideration, will only become worse. ...
Non-Negative Matrix Factorization (NMF) is a valuable matrix factorization technique which produces a "parts-based" decomposition of data sets. Wi-Fi user counts are a privacy-preserving indicator of population movements in smart and connected urban environments. In this paper, we apply NMF with a novel matrix embedding to Wi-Fi user count data from the University of Colorado at Boulder Campus for the purpose of automatically identifying patterns of human movement in a Smart and Connected infrastructure environment.
... The environmental protection agency of the USA has provided national ambient air quality limit for NO 2 is around 100 ppb for 60 min [9]. Even NO 2 concentration above 3 ppm severely affects the human respiratory system causing intense respiratory diseases [18], and prolonged exposure at high concentration may cause cancer. Therefore, the requirement for effective NO 2 sensors is in need with high sensitivity towards environmental monitoring. ...
Layered transition metal dichalcogenide (TMD) materials possess novel and unique semiconducting properties when exfoliated into thin sheets or individual layers. The exfoliation leads to effective sensing towards gas molecule due to the increase in surface-active sites and edge zone disorders. In this work, we present exfoliation of bulk WS2 sheets with liquid-based dispersion technique using facile bath sonication method for NO2 molecule sensing. The exfoliated WS2 nanosheets show reversible and selective response towards NO2 gas molecules operating at room temperature. The sensitive film shows p-type characteristics providing sensor response rate around 27% for 10 ppm NO2 with rapid response and recovery time around 45 s and 60 s, respectively. The sensitive response was further studied at high temperature of 150 °C showing a drastic increase in response rate as 45% with effective response and recovery time. This improvement in NO2 gas sensing was attributed to the facile exfoliation of WS2 nanosheets.
... The symptoms of rhinitis is stuffing nose and sneezing, and its long-term exposure leads to other serious symptoms like atopy. A high amount of inhalation of SO 2 present in ambient air is shown to be linked with increased release of WBC and their precursors from the bone marrow and an elevated number of band cells in peripheral blood [65]. It may also cause damage to developing foetuses and to the reproductive system. ...
-Air quality in most of the mega-cities has been resulted from natural as well as anthropogenic environmental conditions. As compared to developed countries, the issue of air pollution is more serious and complicated in developing countries. Air pollution can be governed by two ways such as emission and transboundary movement of air pollutants. Each factor has different paths and sources through which they enter into atmosphere and affect the surroundings. The problem which needs to be addressed is to find out the paths and causes of emissions. Though there are several air pollutants which comes into focus while taking air pollution issue into consideration, but to explore and solve the behaviour, pattern and chemistry of primary air pollutants (NOx, SOx, CO, VOCs and PM) is a big task. Identification of sources of primary air pollutants is important because they are the only one which is responsible for the production of secondary air pollutants. In this review the focus is given on discussion about general concepts of air pollution by highlighting more specifically primary air pollutants, nature of primary air pollutants, emission budgets and their impact on environmental health by taking plant and human health into consideration. The review ends up with some of the control policies and regulations to curb the concentration of primary air pollutants. Index Terms-Air quality, primary air pollutants, plant health, human health, sources.
... There is a consistent body of evidence that exposure to ambient air pollution is associated with symptoms of cough, bronchitis, respiratory infection, and upper respiratory tract illness in children (Dockery et al., 1989;Raizenne et al., 1996;Schwela, 2000). Although the effects of pollutants appear small, they occur at levels within the national ambient air quality standards of most countries and have the potential to affect large populations of children. ...
... Air pollution is now becoming a challenge to the administration of a city because of its adverse effects on human beings. The acute health effect of suspended particulate matter (SPM), even at short term low levels exposure; include increased daily mortality and hospital admission rates for exacerbation of respiratory disease [1]. Long term exposure to PM2.5 increases the risk of the non accidental mortality. ...
... Heart attacks, respiratory diseases, and lung cancer are all significantly higher in people who breathe dirty air compared to matching groups in cleaner environments [1] . The acute health effect of suspended particulate matter (SPM), even at short term low levels exposure; include increased daily mortality and hospital admission rates for exacerbation of respiratory disease [4] . Living close to busy traffic appears to be associated with elevated risk [5] . ...
... Because of increasing commercialactivities, industrial activities and transportation load air quality is continuously deteriorating. The acute health effect of suspended particulate matter (SPM), even at short term low levels exposure; include increased daily mortality and hospital admission rates for exacerbation of respiratory disease 6 . Long term exposure to PM2.5 increases the risk of the non accidental mortality. ...
This paper presents a case study of Jodhpur City in which residential areas have been analysed for their ambient air quality analysis. Whole experimental and calculative procedure was based on the guidelines of Central Pollution Control Board of India. 24 hourly average concentrations of five criteria pollutants i.e., PM 10 , PM 2.5 , SO 2 , NO 2 and CO were selected for the study for the year 2016 at five different locations of residential areas in Jodhpur city. Observations were taken twice in a week for three months. Results revealed that SO 2 and NO 2 concentrations were within prescribed limit of standard norms. CO concentration was also within permissible limit except few areas. Only particulate matters were crossing the standard limit and specially PM 10. Overall AQI was falling under the category of Good to moderatecategory. Thus, it can be concluded from the study that major pollutionin the residential areas of Jodhpur was due to particulate matters.
... This ground level ozone when breathed, it causes respiratory disease and other health problems 11 . The acute health effect of suspended particulate matter (SPM), even at short term low levels exposure; include increased daily mortality and hospital admission rates for exacerbation of respiratory disease 10 . Long term exposure to PM2.5 increases the risk of the non-accidental mortality. ...
In all the countries industrial development is taking place to meet the society demands and to generate employment in the country. Big industries provide various type of facilities to their employees and one of it is schooling for children. Industry establishes the school in the industrial campuses without considering the pollution in the industrial area. All children studying in these schools are exposed to air pollution caused by the industry. Cement industries can be categories as one of the most polluting industry. Major pollutant released by the cement industry is respirable suspended particulate matter (RSPM). This RSPM is deposited in the respiratory tract of exposed population. In this study effort is made to find the relationship between reduction in forced vital capacity (FVC) of lungs of children with air quality index (AQI) and exposure duration. It was found that reduction in FVC is directly related to AQI and exposure duration. Results indicate that as AQI increases reduction in FVC is increasing. It was also revealed from the study that reduction in FVC is increasing as exposure duration is increasing. FVC of total 431 school children studying in the schools situated in the cement industries were measured, which were exposed to 3 years to 12 years. FVC of 1216 Dr. Suresh Kumar Singh, et al 38 school children those were not exposed to such environment were also measured for comparison purpose and is designated as control population. It was found that FVC of exposed children was reduced upto 19.68 % during their study period. Statistical analysis for 95 % confidence level was done and found that 93.3 % contribution in reduction of FVC is due to AQI and exposure duration.
... (Church, 2007;Church 2010;Kelley, 2008;Nikander, 2010;Valkeinen, 2010). Os vários efeitos nocivos à saúde humana provenientes da exposição do material particulado são bastante conhecidos e estudados na literatura (Schwela, 2000;Godleski et al., 2000;Brook et al., 2010, TD da Silva et al., 2019. No nosso estudo ambos os grupos (atividade física e sedentário) foram expostos a altos níveis de PM10 (ug/m3) e PM2 (ug/ m3) durante toda sua vida, o que pode ter uma potencial influência na modulação da VFC que precisa ser melhor estudada futuramente. ...
... While there are relevant contributions from biogenic sources in the other two sites, their mineral dust source is not as high as in the UH site (or vice versa). These findings further support the importance of accounting for the contribution of biogenic sources as previously reported in other similar studies (Samake et al., 2017;Tuet et al., 2017) as well as the impor- tance of source interactions and dynamics, as it could have considerable influence on the OP of PM 10 . ...
The oxidative potential (OP) of particulate matter (PM) measures PM capability to potentially cause anti-oxidant imbalance. Due to the wide range and complex mixture of species in particulates, little is known about the pollution sources most strongly contributing to OP. A 1-year sampling of PM10 (particles with an aerodynamic diameter below 10) was performed over different sites in a medium-sized city (Grenoble, France). An enhanced fine-scale apportionment of PM10 sources, based on the chemical composition, was performed using the positive matrix factorization (PMF) method and reported in a companion paper (Borlaza et al., 2020). OP was assessed as the ability of PM10 to generate reactive oxygen species (ROS) using three different acellular assays: dithiothreitol (DTT), ascorbic acid (AA), and 2,7-dichlorofluorescein (DCFH) assays. Using multiple linear regression (MLR), the OP contributions of the sources identified by PMF were estimated. Conversely, since atmospheric processes are usually non-linear in nature, artificial neural network (ANN) techniques, which employ non-linear models, could further improve estimates. Hence, the multilayer perceptron analysis (MLP), an ANN-based model, was additionally used to model OP based on PMF-resolved sources as well. This study presents the spatiotemporal variabilities of OP activity with influences by season-specific sources, site typology and specific local features, and assay sensitivity. Overall, both MLR and MLP effectively captured the evolution of OP. The primary traffic and biomass burning sources were the strongest drivers of OP in the Grenoble basin. There is also a clear redistribution of source-specific impacts when using OP instead of mass concentration, underlining the importance of PM redox activity for the identification of potential sources of PM toxicity. Finally, the MLP generally offered improvements in OP prediction, especially for sites where synergistic and/or antagonistic effects between sources are prominent, supporting the value of using ANN-based models to account for the non-linear dynamics behind the atmospheric processes affecting OP of PM10.
... Among ambient air pollutants, PM, ozone, nitrogen dioxide (NO 2 ), and sulphur dioxide (SO 2 ) have the strongest evidence for causing various health disorder [8][9][10]. These have been responsible for 4.2 million deaths globally and are estimated to cause about 16% of the lung cancer deaths, 25% of chronic obstructive pulmonary disease (COPD) deaths, about 17% of ischemic heart disease and stroke, and about 26% of respiratory infection deaths around the world [1,11]. ...
The effect of ambient air pollutants and Asian dust (AD) on absence from school due to sickness has not been well researched. By conducting a case-crossover study, this study investigated the influence of ambient air pollutants and desert sand dust particles from East Asia on absence from school due to sickness. From November 2016 to July 2018, the daily cases of absence due to sickness were recorded in five elementary schools in Matsue, Japan. During the study period, a total of 16,915 absence cases were recorded, which included 4865 fever cases and 2458 cough cases. The relative risk of overall absence in a 10-μg/m3 increment of PM2.5 and a 0.1-km−1 of desert sand dust particles from East Asia were found with 1.28 (95%CI: 1.15–1.42) and 2.15 (1.04–4.45) at lag0, respectively. The significant influence of PM2.5 persisted at lag5 and that of desert sand dust particles at lag2. NO2 had statistically significant effects at lag2, lag3, and lag4. However, there was no evidence of a positive association of Ox and SO2 with absence from school. These results suggested that PM2.5, NO2, and AD increased the risk of absence due to sickness in schoolchildren.
... This is evident from the thick and black smoke haze found sometimes in the air along Nigeria road corridors. The adverse effects associated with human exposure to vehicular exhausts may be impaired respiratory, nervous, and reproductive system as well as kidney malfunction [4]. Airborne pollutants such as SO2 and NOx contribute to acid rain, which can destroy the forest and slowly degrade building mortar, paint, and infrastructure [5]. ...
This study investigated the air pollutants in the ambient air of a typical intercity highway in Nigeria. This was to assess the effect of vehicular emission on air quality along the highway. The results showed that NOX concentrations ranged from 9.9±3.2 to 33.8±3.3 µg/m3 during the wet season and 19.0±1.2 to 35.4±2.3 µg/m3 during the dry season. Sulfur dioxide measured along this highway ranged from 49.7±38.1 to 219±18.1 µg/m3 during the wet season while dry season concentration ranged from 89.1±20.9 to 225.4±57.9 µg/m3. The TSP during the wet season ranged from 54.4±25.6 to 126.8±25.6 µg/m3. These values were below the limits of 250 mg/m3 set by FMEnv., and 150-230 mg/m3 by WHO. However, the TSP measured during the dry season ranged from 85.9±44.6 to 277.8±213.5 µg/m3. The average correlations between NOX, SO2, and TSP measured during wet and dry seasons and the traffic density were 0.7, 0.6 and 0.7, respectively. Air pollution along the Nigerian highway is highly linked to vehicular activities.
... Nonetheless, with natural ecosystems affected heavily by the increasing impacts of urbanisation a significant opportunity in preserving and enhancing biodiversity is possible. Fast economic development can be detrimental to environment through land-use change, consumption of resources, and pollution (Schwela, 2000). Significant volumes of literature stress the contribution of urban forests in reducing pollution levels and offsetting GHGs emissions in cities (McPherson, 1998;McPherson and Rowntree, 1993;Nowak et al., 2006;Nowak and Crane, 2002;Yang et al., 2005;Zhao et al., 2010). ...
... West (1997) a West a Sweeting (2004) zjistili, že rozdíly způsobené SES mohou být silné na začátku života a slábnout s nástupem do školy, která funguje jako faktor homogenizace. Nejen v evropském městském prostoru je za nejzávažnější environmentální faktor působící na zdraví označována kvalita ovzduší (Schwela 2000). Krátkodobá i dlouhodobá expozice znečištěnému ovzduší ovlivňuje výskyt respiračních a gastrointestinálních onemocnění, alergií, kardiovaskulárních a metabolických onemocnění, vývojových a reprodukčních poruch a nádorových onemocnění (Sanyal et al. 2018;Li et al. 2018;Bourdrel et al. 2017;Manisalidis et al. 2020;Cramer et al. 2020). ...
The prevalence of inequalities in the general health position of communities can be assessed by using selected determinants. The aims of this article are three-fold: 1) to apply a comprehensive approach to the assessment of inequalities in the general health position of communities, 2) to determine the spatial differentiation of determinants, and 3) to present selected assessment methods and their impact on the results. For the presenting a quantitative assessment of these inequalities in health status in communities, a composite indicator (Health Index) was developed. This Health Index is composed of 8 areas of evaluation and 60 indicators which include, amongst others, determinants of health status and health care at district level (LAU 1) in the Czech Re-public. The data are evaluated using multicriteria decision-making methods (the WSA and TOPSIS methods). Findings suggest that, when all eight domains are assigned the same weight of one, the spatial differentiation among the districts is similar when using both methods. If different weightings are assigned to the districts, changes occur in both the index values and the rankings of the analysed districts. For example, the allocation of weightings in both methods results in a rearrangement of the ranking of districts for which the Health Index is around the average.
The development of effective and efficient materials for the selective and sensitive detection of toxic gases and volatile organic compounds is crucial for protecting human health and the environment. In...
En este estudio, se analizó como afecta el grave problema de la contaminación actual en agua, aire y suelo debido a actividades antropogénicas de la ciudad de Morelia, Michoacán. Se ha realizado un análisis del estado actual de la tecnología de celdas de combustible, identificándose a la celda de combustible de óxido sólido (SOFC), como un excelente candidato. Esto permitiría determinar la posibilidad de utilizar una celda SOFC como generador de energía eléctrica a partir de biogás compuesto principalmente de metano y bióxido de carbono como combustible. Al generar energía eléctrica a partir de estos gases que provienen de rellenos sanitarios, se pretende establecer un proceso de optimización energética y sustentable.
This study involves field data and analytical technique into spatially map air pollution levels on account of traffic volumes, vehicle speeds and grades of roads at relatively high traffic volumes signalized intersections in Amman; capital of Jordan . The study was conducted by collecting traffic and air pollution data at twelve locations in four streets, each street located in a different zone. Also the data collection process was conducted at many highly jam traffic time periods. The highest air pollution level was measured at 7th circle in Abdullah Gosheh street, where was the maximum Average traffic volume. And the least air pollution level of the studied areas was at Anas Bin Malek Street which is located in Ras Al-Ain zone , so that it can be an acceptable residential area. Results showed clearly that the highest air pollution levels found near traffic signals and at the stop lines of them, and theses concentrations decrease while being more far from traffic signals. Also, increasing in road gradients leads to a decrease in speed of vehicles, this leads to an increase in the pollutants concentrations. The highest air pollution concentrations were 0.7, 0.6, 9.9, and 0.6 (in ppm) of NO2, SO2, CO and SPM respectively. The R-square value, square of relative coefficient, of the relationships between NO2, SO2, CO & SPM concentrations and traffic volume were approximately: 0.9135, 0.8822, 0.8977, and 0.8934 respectively. It is noticed that traffic volume is the most significant factor that affects SO2, NO2, CO & SPM concentrations. This research has illustrated that the pollutants’ concentrations are larger than recommended concentrations of World Health Organization (WHO) in most locations of the studied areas, and that showing a necessity for a standard air quality monitoring, traffic management arrangement and effective procedures should be followed to reduce the resulted pollution.
III-nitrides are attracting considerable attention as promising materials for a variety of applications due to their wide bandgap, high electron mobility, high thermal stability and many other exceptional properties. This...
The composites of CeO2 nanoparticles and MoS2 nanosheets are prepared by hydrothermal method. It is found that the CeO2/MoS2 composites exhibit the better NO2-sensing response at room temperature (RT), with the sensitivity towards 5 ppm NO2 higher than that of pure MoS2 by 69.1%, and 85% of the resistance can be returned within 900 s. The sensor also possesses the characteristics of a fast response, a reliable long-term stability and an excellent selectivity. Based on the first-principle calculations, the adsorption energy of CeO2/MoS2 composites to NO2 is much higher than that of MoS2, enhancing the adsorption ability of NO2. Moreover, the CeO2/MoS2 composites could suppress the aggregation of nanosheets and nanoparticles, and thus provide plenty of active sites for adsorption of NO2 molecules. As a result, the room-temperature NO2-sensing response is enhanced substantially.
The rate of oxidative damage of aliphatic amino acids and dipeptides by the environmental pollutant nitrate radical (NO3·) in an aqueous acidic environment was studied by laser flash photolysis. The reactivity dropped by a factor of about four for amino acid residues with secondary amide bonds and by a factor of up to nearly 20 for amino acid residues with tertiary amide bonds, compared with that in acetonitrile. According to density functional theory studies, the lower reactivity is due to protonation of the amide moiety, whereas in neutral water, hydrogen bonding with the amide should have little impact on the absolute reaction rate compared with that in acetonitrile. This finding can be rationalized by the high reactivity and broad reaction pattern of NO3·. Although hydrogen bonding involving the amide group raises the energies associated with some electron transfer processes, alternative low-energy pathways remain available so that the overall reaction rate is barely affected. The undiminished high reactivity of NO3· toward aliphatic amino acid residues in a neutral aqueous environment highlights the health-damaging potential of exposure to the combined air pollutants nitrogen dioxide (NO2·) and ozone (O3).
Innovative chemiresitive gas sensors with strong sensing qualities that operate at room temperature are much more appealing due to their properties of long-life cycle, high stability, and lower usage of power. As we know, n-type semiconducting metal oxide like SnO2 received a lot of interest for its gas sensing applications. The rapid progress of different synthesis processes has allowed researchers to investigate a wide range of new nanostructures and their incorporation into smart gas sensing devices. Generally, conventional metal oxide-based sensors are functioned at very high a temperature, which causes high power consumption and low selectivity. Therefore, to remove this issue, metal oxides doped with various nanostructures are the first choice due to their advantages: high surface-area-to-volume ratio, efficient electron transfer, improved and adjustable surface reactivity, and quick access response time, and short recovery time. In this review, we have discussed the preparation of SnO2 nanowires through various methods and discussed the state of the art of vapour or gas sensors based on tin oxide nanowires and can exhibit sensing properties at room temperature. An overview of the wealth of material, methods, and sensing mechanisms like response time, analytical ranges, and operating temperatures are also explained. In the last section, we discussed the current status and challenges and depicted the potential future aspects.
In view of their unique characteristics and properties, palladium decorated nanostructures have been used not only in the field of nanomedicine, nanodrug delivery, automobiles, construction, and agrochemical but also for diverse advanced catalytic technologies and gas sensing applications. This comprehensive review sheds light on general synthetic approaches encompassing hydrothermal synthesis, co-precipitation, solvothermal, sol–gel, and thermal treatment, among the preparative methods for the syntheses of Pd-decorated nanostructures and their catalytic and chemiresistive gas sensing applications. In addition to this, fundamental aspects of being an ideal nanomaterial are also discussed, such as morphology, selectivity, stability, reproducibility of the material. Moreover, inthe case of catalytic applications, various reactions such as coupling, addition, oxidation, reduction, hydrogenation, water splitting, etc. The Pd-decorated nanostructures are used as catalysts, and their interference has been explained. While, for the gas sensing application, an overview of the wealth of material, methods, and sensing mechanisms like response time, analytical ranges, and operating temperatures are also explained. Furthermore, the rise and journey of Pd-decorated based catalysts and gas sensors will inspire a new generation of chemists to tailor and design robust catalysts and sensors that can effectively tackle major environmental challenges and help replace noble metals in advanced catalytic and sensing applications.
The power consumption of the chemical resistive gas sensor should be considered when its performance is developed. One of the most effective methods for reducing the power consumption is to make the gas sensor work at room temperature. A tin disulfide (SnS2) nanoparticle-based gas sensor with high sensitivity and fast recovery is proposed in this paper for detecting the nitrogen dioxide (NO2). The experimental results show that the SnS2 nanoparticle-based gas sensor has excellent gas sensing performance at room temperature, including high sensitivity, rapid response/recovery speed (28 s/1 s), high selectivity and good repeatability and reversibility. The main reason for the excellent performance of the SnS2 nanoparticle-based gas sensor is mainly attributed to the unique physical affinity and favorable electronic band positions of the SnS2 material, which promotes the physisorption and charge transfer of NO2 gas molecules. It is expected that this work can provide guidance for the real-time rapid detection of NO2 at room temperature.
This paper presents a case study of Jodhpur City in which an attempt has been made to prepare an inventory of pollutants (PM 10 , PM 2.5 , SO 2 , NO x , CO) at regional level to know the current cumulative air pollution load in the study area and thereafter computing Air Quality Index by computing sub index for every pollutant. Monitoring stations were set up at seven different locations and samples have been analysed and subsequently air quality index has been computed. The results reveal that gaseous pollutants such as SO 2 , NO 2 & CO are within the permissible limits. PM 2.5 levels exceed the prescribed National Ambient Air Quality standards (NAAQS) and PM 10 levels also exceeded the prescribed NAAQS during all the monitoring location thus particulate matter is the predominant cause of air pollution in the study area. The AQIs were calculated using IND-AQI procedure. It has been observed that the calculated AQIs value for SO 2 falls under 'good' category. The calculated AQIs values for NO 2 & CO fall under 'good' and 'satisfactory' categories. The calculated AQIs values of PM 10 fall under 'moderate' and 'poor' categories. The calculated AQIs values of PM 2.5 fall under 'moderate', 'poor' and also in 'very poor' categories. The overall AQI was found to fall under the category 'Poor' owing to PM 2.5. Thus it is observed that PM 2.5 is responsible pollutant at these seven locations in Jodhpur.
Nitrogen dioxide (NO2) and nitric oxide (NO) collectively called NOx are toxic gases which are emitted during combustion process. Selective detection of NOx at low concentration is essential for human health and environment monitoring. The present study has explored the use of 2D few-layer manganese phosphoselenide (MnPSe3) towards selective and reversible NOx (NO2 and NO) sensing under ambient conditions. Few layer MnPSe3 obtained by solvent exfoliation of bulk material is used as uniform thin film for NOx gas sensing. The sensor shows responses of 685% and 137% for the detection of 1 ppm of NO2 and NO gas respectively. The total NOx (sum of NO and NO2) at different ratios of the constituents can be detected as well. The response follows Langmuir-type behavior with high selectivity towards NOx-based gases in presence of H2, O2, CO, CO2 and C2H2. The sensor is completely reversible with fast response and recovery times under ambient conditions. Temperature dependent studies indicate that the sensor response increases upto a certain temperature and then decreases in presence of humidity. The effect of humidity is studied as well.
Chronic exposure to diesel exhaust particle (DEP) is considered to provoke dysfunction of the blood-brain barrier, but the detailed molecular mechanism remains unclear. In this study, we investigated the toxic effects of five DEP components against human vascular cells and found that, among them, 9,10-phenanthrenequinone (9,10-PQ), a major tricyclic quinone in DEP, most potently elicits the cellular toxicities. Additionally, treatment with 9,10-PQ at its cytolethal concentrations (more than 2 μM) facilitated the production of reactive oxygen species (ROS), caspase activation, and DNA fragmentation in human brain microvascular endothelial (HBME) cells, inferring that high concentrations of 9,10-PQ elicit the cell apoptosis through the ROS-dependent mechanism. Measurement of trans-endothelial electrical resistance and paracellular permeability showed that treatment with sublethal concentrations (less than 1 μM) of 9,10-PQ elevates permeability across HBME cell monolayer. Immunofluorescence observation and Western blotting analysis also revealed that the 9,10-PQ treatment remarkably down-regulated the intercellular localization and expression of claudin-5 (CLDN5), a tight junctional protein that plays a key role in function of the blood-brain barrier, and the down-regulation was markedly recovered by pretreatment with a proteasome inhibitor Z-Leu-Leu-Leu-CHO. This result may indicate that sublethal concentrations of 9,10-PQ facilitate the dysfunction of the endothelial cell barrier through lowering in the expression and proteasomal proteolysis of CLDN5. The treatment with 9,10-PQ promoted nitric oxide (NO) production presumably through the induction of inducible NO synthase. In addition, the 9,10-PQ-mediated down-regulation of CLDN5 was ameliorated and deteriorated by pretreating with a scavenger and donor, respectively, of NO. Similarly to the 9,10-PQ treatment, treatment with a donor of peroxynitrite, a highly reactive oxidant formed by the reaction of NO and superoxide anion, resulted in the marked reduction of CLDN5 expression and elevation of 26S proteasome-based proteolytic activities. Thus, it is suggested that the formation of NO and peroxynitrite participates in the mechanism of brain endothelial cell barrier dysfunction elicited by 9,10-PQ.
Our knowledge of the adverse health effects from exposure to low levels of air pollution is still insufficient. Early indicators, such as respiratory symptoms, need more attention. We made use of t ...
Objective: To investigate whether outdoor air pollution levels in London influence daily mortality.
Design: Poisson regression analysis of daily counts of deaths, with adjustment for effects of secular trend, seasonal and other cyclical factors, day of the week, holidays, influenza epidemic, temperature, humidity, and autocorrelation, from April 1987 to March 1992. Pollution variables were particles (black smoke), sulphur dioxide, ozone, and nitrogen dioxide, lagged 0-3 days.
Setting: Greater London.
Outcome measures: Relative risk of death from all causes (excluding accidents), respiratory disease, and cardiovascular disease.
Results: Ozone levels (same day) were associated with a significant increase in all cause, cardiovascular, and respiratory mortality; the effects were greater in the warm season (April to September) and were independent of the effects of other pollutants. In the warm season an increase of the eight hour ozone concentration from the 10th to the 90th centile of the seasonal range (7-36 ppb) was associated with an increase of 3.5% (95% confidence interval 1.7 to 5.3), 3.6% (1.04 to 6.1), and 5.4% (0.4 to 10.7) in all cause, cardiovascular, and respiratory mortality respectively. Black smoke concentrations on the previous day were significantly associated with all cause mortality, and this effect was also greater in the warm season and was independent of the effects of other pollutants. For black smoke an increase from the 10th to 90th centile in the warm season (7-19 µg/m3) was associated with an increase of 2.5% (0.9 to 4.1) in all cause mortality. Significant but smaller and less consistent effects were also observed for nitrogen dioxide and sulphur dioxide.
Conclusion: Daily variations in air pollution within the range currently occurring in London may have an adverse effect on daily mortality.
Key messages
Evidence from other countries suggests that similar levels of pollution may be associated with short term health effectsThis study suggests that air pollution due to particles and ozone may be associated with increased daily mortality in LondonThe evidence is less convincing for nitrogen dioxide and sulphur dioxideIt would be prudent to assume that these associations are causal and to reduce air pollution levels with the help of appropriate abate- ment policies
The Air Pollution and Hearth: a European Approach (APHEA) project is a coordinated study of the short-term effects of air pollution on mortality and hospital admissions using data from 15 European cities, with a wide range of geographic, sociodemographic, climatic, and air quality patterns. The objective of this paper is to summarize the results of the short-term effects of ambient oxidants on daily deaths from all causes (excluding accidents). Within the APHEA project, six cities spanning Central and Western Europe provided data on daily deaths and N0 2 and/or O 3 levels. The data were analyzed by each center separately following a standardized methodology to ensure comparability of results. Poisson autoregressive models allowing for overdispersion were fitted. Fixed effects models were used to pool the individual regression coefficients when there was no evidence of heterogeneity among the cities and random effects models otherwise. Factors possibly correlated with heterogeneity were also investigated. Significant positive associations were found between daily deaths and both NO 2 and O 3 . Increases of 50 f^g/m 3 in N0 2 (1-hour maximum) or O 3 (1-hour maximum) were associated with a 1.3% (95% confidence interval 0.9-1.8) and 2.9% (95% confidence interval 1.0-4.9) increase in the daily number of deaths, respectively. Stratified analysis of NO 2 effects by low and high levels of black smoke or O 3 showed no significant evidence for an interaction within each city. However, there was a tendency for larger effects of NO 2 in cities with higher levels of black smoke. The pooled estimate for the O 3 effect was only slightly reduced, whereas the one for N0 2 was almost halved (although it remained significant) when two pollutant models including black smoke were applied. The internal validity (consistency across cities) as well as the external validity (similarities with other published studies) of our results on the 0 3 effect support the hypothesis of a causal relation between O 3 and all cause daily mortality. However, the short-term effects of N0 2 on mortality may be confounded by other vehicle-derived pollutants. Thus, the issue of independent NO 2 effects requires additional investigation. Am J Epidemiol 1997; 146:177-85.
Objective: To test the efficacy of a graded aerobic exercise programme in the chronic fatigue syndrome. Design: Randomised controlled trial with control treatment crossover after the first follow up examination. Setting: Chronic fatigue clinic in a general hospital department of psychiatry.
The Pollution Effects on Asthmatic Children in Europe (PEACE) study is a multicentre study of the acute effects of particles with a 50% cut-off aerodynamic diameter of 10 μm (PM10), black smoke (BS), sulphur dioxide (SO2) and nitrogen dioxide (NO2) on the respiratory health of children with chronic respiratory symptoms. The study was conducted in the winter of 1993/1994 by 14 research centres in Europe. A total of 2,010 children, divided over 28 panels in urban and suburban locations, was followed for at least 2 months. Exposure to air pollution was monitored on a daily basis. Health status was monitored by daily peak expiratory flow (PEF) measurements and a symptom diary. The association between respiratory health and air pollution levels was calculated with time series analysis. Combined effect estimates of air pollution on PEF or the daily prevalence of respiratory symptoms and bronchodilator use were calculated from the panel-specific effect estimates. Fixed effect models were used and, in cases of heterogeneity, random effect models. No clear associations between PM10, BS, SO2 or NO2 and morning PEF, evening PEF, prevalence of respiratory symptoms or bronchodilator use could be detected. Only previous day PM10 was negatively associated with evening PEF, but only in locations where BS was high compared to PM10 concentrations. There were no consistent differences in effect estimates between subgroups based on urban versus suburban, geographical location or mean levels of PM10, BS, SO2 and NO2. The lack of association could not be attributed to a lack of statistical power, low levels of exposure or incorrect trend specifications. In conclusion, the PEACE project did not show effects of particles with a 50% cutoff aerodynamic diameter of 10 μm, black smoke, sulphur dioxide or nitrogen dioxide on morning or evening peak expiratory flow or the daily prevalence of respiratory symptoms and bronchodilator use.
Cause-specific deaths by day for the years 1973 to 1980 in Philadelphia, Pennsylvania, were extracted from National Center for Health Statistics mortality tapes. Death from accidents (International Classification of Disease, Revision 9 greater than or equal to 800) and deaths outside of the city were excluded. Daily counts of deaths were regressed using Poisson regression on total suspended particulate (TSP) and/or SO2 on the same day and on the preceding day, controlling for year, season, temperature, and humidity. A significant positive association was found between total mortality (mean of 48 deaths/day) and both TSP (second highest daily mean, 222 micrograms/m3) and SO2 (second highest daily mean, 299 micrograms/m3). The strongest associations were found with the mean pollution of the current and the preceding days. Total mortality was estimated to increase by 7% (95% CI, 4 to 10%) with each 100-micrograms/m3 increase in TSP, and 5% (95% CI, 3 to 7%) with each 100-micrograms/m3 increase in SO2. When both pollutants were considered simultaneously, the SO2 association was no longer significant. Mortality increased monotonically with TSP. The effect of 100 micrograms/m3 TSP was stronger in subjects older than 65 yr of age (10% increase) compared with those younger than 65 yr of age (3% increase). Cause-specific mortality was also associated with a 100-micrograms/m3 increase in TSP: chronic obstructive pulmonary disease (ICD9 490-496), +19% (95% CI, 0 to 42%), pneumonia (ICD9 480-486 & 507), +11% (95% CI, -3 to +27%), and cardiovascular disease (ICD9 390-448), +10% (95% CI, 6 to 14%). These results are somewhat higher than previously reported associations, and they add to the body of evidence showing that particulate pollution is associated with increased daily mortality at current levels in the United States.
A cohort of approximately 100 student nurses in Los Angeles was recruited for a diary study of the acute effects of air pollution. Smoking histories and presence of asthma and other allergies were determined by questionnaire. Diaries were completed daily and collected weekly for as long as 3 yr. Air pollution was measured at a monitoring location within 2.5 miles of the school. Incidence and duration of a symptom were modeled separately. Pack-years of cigarettes were predictive of the number of episodes of coughing (p less than 0.0001) and of bringing up phlegm (p less than 0.0001). Current smoking, rather than cumulative smoking, was a better predictor of the duration of a phlegm episode (p less than 0.0001). Controlling for personal smoking, a smoking roommate increased the risk of an episode of phlegm (odds ratio [OR] = 1.41, p less than 0.001), but not of cough. Excluding asthmatics (who may be medicated), increased the odds ratio for passive smoking to 1.76 (p less than 0.0001). In logistic regression models controlling for temperature and serial correlation between days, an increase of 1 SD in carbon monoxide exposure (6.5 ppm) was associated with increased risk of headache (OR = 1.09, p less than 0.001), photochemical oxidants (7.4 pphm) were associated with increased risk of chest discomfort (OR = 1.17, p less than 0.001) and eye irritation (OR = 1.20 p less than 0.001), and nitrogen dioxide (9.1 pphm) was associated with increased risk of phlegm (OR = 1.08 p less than 0.01), sore throats (OR = 1.26, p less than 0.001), and eye irritation (OR = 1.16, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
There is still not enough evidence from epidemiological studies alone to establish whether health effects are causally related to NO2. From the overall evidence, including findings from toxicological studies, it seems reasonable to assume that NO2 is at least partially responsible for the observed health effects of urban pollution mixtures. The World Health Organization Centre for Europe recommends in the revised Air Quality Guidelines for Europe as a long-term guideline for NO2 an annual value of 40 μg/m3 (21 ppb) and, based on clinical data, a 1-h guideline of 200 μg/m3 (100 ppb). The directive of the Economic Commission for Europe proposes the same values as limit values to protect human health. The short-term value of 200 μg/m3 averaged over 1h must not be exceeded during more than 8 out of 8760 hours per calendar year; the long-term limit value will be 40 μg/m3 averaged over a calendar year.
This chapter focuses on the effects of exposure to ambient concentrations of carbon monoxide. Severe poisoning by carbon monoxide often results in lasting damage to the central nervous system (CNS). This may be delayed, progressive, irreversible, and lethal. Though anoxia is undoubtedly important, autoimmune processes leading to a spongiform degeneration or leukoencephalopathy have been suggested. Leukoencephalopathy is not seen following acute exposure to low concentrations of carbon monoxide, but there is some dispute over whether more subtle effects on the CNS may occur as a result of repeated low-level exposures. Carbon monoxide exerts its toxic effects by reducing the capacity of hemoglobin to transport oxygen and by interfering with the release of such oxygen as is carried. The hypoxia produced is particularly dangerous in that the partial pressure of oxygen is maintained despite a fall in the amount of oxygen per unit volume of blood. Thus, early stimulation of the respiratory centre is delayed. Moreover, exposure to carbon monoxide is much more likely to lead to fainting on exertion than exposure to low concentrations of oxygen.
The primary photochemical reactions between O3 and NO2 produce many secondary pollutants, such as peroxyacetyl nitrate, nitric acid, nitrates, and other nitrogen oxides. Because of the photolytic instability of most of these species in sunlight, the concentrations of these pollutants are low. Although the seasonal, temporal, and spatial patterns of O3 and NO2 in ambient air differ, under certain atmospheric conditions, the two pollutants may undergo a chemical reaction outside the photochemical cycle. These reactions can produce a significant number of chemical species, some of which may be even more toxic than their precursors. Although primarily an outdoor air pollutant, indoor O3 concentrations may reach levels at which significant chemical reactions could occur between this oxidant and other constituents of indoor air, when O3 is introduced either through infiltration of building structures or via a building ventilation air intake system. Some experimental evidence from animal studies implicates many of these secondary pollutants in the induction of pathophysiological changes. However, their relative toxicity is not yet well understood, and some of these compounds have not yet been investigated.
This chapter describes the effect of sulfur dioxide (SO2) on health. The toxicologically significant sulfur oxides are the gaseous SO2, produced primarily from combustion sources, and sulfuric acid and ammonium bisulfate, the secondarily derived particulate strongly acidic sulfates. Controlled clinical studies strongly suggest that asthmatics are more sensitive to SO2, responding with bronchoconstriction at much lower exposure levels than do normal individuals. Toxicologically, exposure to high levels of SO2 are needed before there are significant changes in pulmonary defenses, but exposure to lower levels of acidic sulfates will alter mucociliary transport, alveolar clearance of particles, and airway reactivity, even in normal individuals. While the exact mechanisms underlying the toxicity of sulfur oxides are not known with certainty, the main response to SO 2, that is, bronchoconstriction, is because of contraction of airway smooth muscle via the parasympathetic reflex and/or following release of humoral mediators. This is probably due most directly to the bisulfite ion produced upon dissolution of SO2 in airway fluids. On the other hand, the toxicity of acid sulfates is most likely because of the deposition of H+ on airway surfaces, and it appears that a threshold exists for both the number of deposited acid particles as well as the mass concentration needed to produce any biological response.
Experimental measurements of ozone (O3) uptake are needed for validation of dosimetry model parameters and in predictions as well as for determining factors affecting uptake and for making comparisons between subpopulations or across species. In this study, 10 healthy adult male subjects were exposed to 0.3 ppm O3while seated and breathing naturally through the nose or mouth. Total respiratory tract O3uptake, spontaneous breathing parameters, and respiratory gas exchange were measured for 10 min under steady-state conditions. The exposure protocol was replicated in each subject approximately 2 weeks after the first visit. On each visit, health exams were performed and spirometric lung measurements were obtained. The experimental design provided comparisons of total O3uptake during nasal and oral breathing, differences in uptake in an individual at two time points, and an examination of between-subject variability in O3uptake. Exposure to O3had no effect on the breathing parameters or gas exchange. Oral and nasal breathing frequency averaged 16.2 ± 1.1 (SE) and 16.0 ± 1.2 breaths per minute with tidal volumes averaging 651 ± 46 and 669 ± 67 ml, respectively. A significant correlation (p< 0.01) was found for the minute volume during resting breathing with the percentage of uptake. The percentage of O3uptake was consistently higher (p= 0.02) during oral breathing (76.5% ± 3.3) than during nasal breathing (73.1% ± 3.0) although this difference may not be biologically significant. The variability in percentage of uptake between subjects was substantial with calculated uptakes ranging from 51 to 96%, a difference of about 45%. Variability in percentage of uptake for an individual was less with the maximal difference between the first and second visits being about 20%; the average difference, however, was only about 3%. We conclude that total percentage of O3uptake is approximately 75% in adult males during resting breathing. It is slightly greater during oral than during nasal breathing, will vary considerably among subjects, and is moderately reproducible within a subject.
This paper presents results of two years of monitoring and research on urban particulates with a focus on submicrometer particles, conducted as a part of an ongoing program on comprehensive characterization of fine airborne particulates and their effect on environmental and human exposures. A large number of data has been collected by the Air Monitoring and Research Station operating in the centre of the subtropical city of Brisbane. The Station is equipped in instrumentation for measurements of particle size distributions in submicrometer and supermicrometer ranges in addition to the standard instrumentation for monitoring of the criteria pollutants (PM10, ozone, sulphur dioxide, nitrogen oxides and carbon monoxide). The focus of this paper is on presenting results related to characterization of particle size distribution and concentration trends in the study period, correlation between particle characteristics measured by different instruments, correlation between particle and gaseous data and preliminary conclusions on source characteristics and source contribution for the investigated area. The average submicrometer particulate concentration in the study period was 7.4×103 particles cm-3, and the average number median diameter was 40nm. The best correlated data are those for submicrometer particles and carbon monoxide and nitrogen oxides, suggesting the same source type. The lack of correlation between submicrometer and supermicrometer particle concentration data implies different sources for particles in these two ranges. Particle spectral analysis and correlation with gaseous data, indicate that motor vehicle emissions constitute the main source of ultrafine particles in the study area.
Because of the history of health problems traceable to the exhaust of ice resurfacing machines, state sanitarians used detector tubes to measure carbon monoxide (CO) and nitrogen dioxide (NO[sub 2]) levels in enclosed ice arenas in Vermont during high school hockey games. Five of eight arenas had average game CO measurements of 30 ppm carbon monoxide or more. Two of the three periods of play had average CO readings in excess of 100 ppm in one arena. Only six arenas had the complete series of nitrogen dioxide measurements. One had an average game NO[sub 2] level of 1.2 ppm. Two had one or more periods of play that averaged in excess of 0.5 ppm. Despite the ample documentation of the hazards of operating combustion-powered resurfacing machines inside enclosed ice arenas, a significant portion of the arenas had undesirable levels of carbon monoxide or nitrogen dioxide. Ice arenas should be routinely monitored for air contaminants. Considerations should be given to the purchase of electric ice resurfacing machines for new arenas and arenas that have air contamination that cannot be resolved with ventilation.
A national cooperative study was conducted from 1974 to 1976 in twenty-four areas located in six French cities, in order to investigate the relationships of air pollution to ventilatory function and the prevalence of respiratory symptoms. The concentrations of the following pollutants were daily measured: SO2, suspended particulates, NOx. The population included men and women, non manual workers, aged 25 to 59, and children, aged 6 to 10. The respiratory symptoms and other characteristics of the subjects were recorded and their ventilatory function was measured with a dry expirograph.
The main results were as following: a) in adults of both sexes, the pollution in SO2 was associated with the prevalence of lower respiratory symptoms, b) in children, it was associated with the prevalence of upper respiratory symptoms, c) in both adults and children, the higher the SO2 concentration, the lower the FEV1. d) no other polluant was related to respiratory diseases.
The effect of lead exposure on β2-adrenoceptor density and catecholamine response was studied in 26 male workers and 1 female worker, exposed to lead on average for 6 years. The systolic blood pressure in lead workers (101–160 mmHg, 124.4 ± 14.7 mmHg) was found to be significantly higher than in controls (97–134 mmHg, 115.4 ± 10.4 mmHg,p< 0.01) as was plasma norepinephrine (0.51 ± 0.1 μg/liter vs 0.24 ± 0.05 μg/liter,p< 0.01). The density of lymphocyte β2-adrenergic receptors (Bmax) in lead-exposed workers was 86% lower than that in controls (0.15 ± 0.08 vs 1.08 ± 0.29 fmol/0.1 × 106cells;p< 0.01). The dissociation constants (Kd) of [125I]iodocyanopindolol were 93.6 ± 42.6 and 87.9 ± 42.7 pMin lead-exposed workers and controls, respectively. Multiple linear regression analysis showed that elevation of systolic pressure was closely related to (a) blood lead levels, (b) decreased β2-adrenergic receptor density, and (c) increased plasma catecholamine levels in lead-exposed workers. Linear regression analysis revealed that both plasma norepinephrine levels and β2-adrenoceptor density (Bmax) were highly correlated with both systolic blood pressures and blood lead levels in lead-exposed workers, and a highly significant negative correlation was found to exist betweenBmaxand plasma norepinephrine levels (r= −0.82,p< 0.001). These data therefore demonstrate that there is a close relationship between elevated plasma catecholamine levels, decreased β2-adrenergic receptors, and elevated blood pressure in lead-exposed workers.
A study was conducted from October 1991 to September 1992 in the Paris metropolitan area to assess the exposure of city-dwellers who are directly or indirectly exposed to car exhaust fumes during their daily movements. The study concentrated primarily on trips in automobiles, although other transportation modes were also included: subway, bus, and trips made on foot. Carbon monoxide (CO) and six monocyclic aromatic hydrocarbons (MAHs) were identified as being indicators of automotive exhaust and/or being toxic. The average concentrations collected inside an automobile in central Paris were 12 ppm for carbon monoxide, 46 (ig/m3 for benzene, and 260 μg/m for toluene. Lesser quantities were recorded for the other modes of transportation: 2-5 ppm of CO, 12-25 μg/m for benzene, and 80-110 μg/m for toluene—that is, three times more than in Parisian surrounding air. Further measurements showed that in a moving vehicle, the concentration of pollutants is caused by the exhaust of neighboring vehicles. Consequently, correlations between pollutants are very high, and the relationship between concentrations of CO and MAHs is identical to that found in stationary monitoring stations. From a health standpoint, reference values established by the World Health Organization (WHO) for CO are not exceeded when an individual only travels from home to work. However, if that individual uses a personal car at other times during the day, the reference value for eight hours (10 ppm) may be exceeded. This study shows that in the Paris area, commuting to work in cars contributes an average of 20-30% of the daily inhaled amount of benzene for a nonsmoking city-dweller.
A mathematical model is developed to predict the resultant carbon monoxide level in a residential area located near a vehicular tunnel entry. The highway to the tunnel is adjacent to hillsides. The tunnel is ejecting polluted air with a speed of 5 m/s and a carbon monoxide concentration of 200 ppm. A waiting queue of vehicles forms in front of the tunnel entry at rush hours. The effect due to the tunnel jet together with this vehicular queue is simulated under the action of wind. This mathematical model is set up from a system of recirculation flow equations using a two‐equation k‐ε turbulent model. The equations are solved numerically for primitive variables with three‐dimensional effect. The set of partial differential equations are discretized using the control volume method and numerical scheme employed is the SIMPLER. The predicted results are useful to justify the environmental impact on the residential area located 300 m within the tunnel entry.
In Reply.
—In response to Mr Glaser's comments, we repeated our multivariate analysis, controlling for 5 levels of education (reflecting socioeconomic status) and 3 levels of occupational status (lifetime blue collar, lifetime white collar, mixed blue collar and white collar). The effect estimate for tibia bone lead remained unchanged from that reported in Table 4 in our article, suggesting that these factors cannot explain the link between bone lead and hypertension.To address the first point of Dr Staessen and colleagues, lower blood pressure cutoff values (>140 mm Hg systolic and/or 90 mm Hg diastolic) were used to define hypertension. Tibia bone lead continued to contribute to the prediction of hypertension, and the magnitude of the effect was even higher as shown in Table 4. Our analysis of bone lead in relation to blood pressure as a continuous variable is still in progress.In the second point, Staessen et al raise the
A methodology for measuring the frequency distribution of carbon monoxide (CO) exposure in a representative sample of an urban population has been developed and applied in two urban areas: Washington, DC, and Denver, CO during the winter of 1982-1983. Exposure data using personal exposure monitors (PEMS) were collected, together with activity data from a stratified probability sample of residents living in each of the two urban areas. Well established survey sampling procedures were used for the selection of individuals. The resulting exposure data permit estimates of CO exposure for the eligible populations of the two areas, as well as statistical comparisons between population subgroups (e.g., commuters vs. noncommuters and residents with and without gas stoves). Results indicated that over 10% of the residents in Denver and 4% of the Washington, DC, residents were exposed to CO levels above 9 ppm for 8 h during the study period. The data also provide evidence for judging the accuracy of exposure estimates calculated from fixed site monitoring data.
In order to evaluate the severity of carbon monoxide (CO) pollution in Taipei, this study conducted a survey of commuting patterns (in a district) for random samples of primary school students and adult workers, and carried out CO measurements in vehicles and near roadsides. A Monte Carlo simulation was then implemented to estimate 1- and 8-h CO exposure levels for the population. The microenvironment of the roadside included both the sidewalk and the corridor (a sheltered walkaway further removed from the road than the sidewalk). By computer simulations, this study showed that commuters on motorcycles and public buses were exposed to the highest CO exposure levels among all commuters on the roads in Taipei. This study also demonstrated that the Monte Carlo simulation method could better estimate CO exposure levels for the general public. It was found that roadside-fixed monitoring stations operated by the Taipei BEP (Bureau of Environmental Protection) underestimated the general population's 1-h CO exposure levels. For adult workers, the roadside-fixed monitoring stations reasonably estimated the roadside business workers' 8-h CO exposure levels, but overestimated the exposure levels of general adult workers commuting by public bus, except for bus drivers whose CO exposure levels were underestimated. It is suggested that the computer simulation method can be used to better guide air quality management plans instead of only using the fixed-site monitoring data. The simulated results indicate that the CO exposure levels of commuters on motorcycles and public buses are high enough that prompt control measures are warranted in Taipei.
Personal 1 h mean CO exposures of preschool children in two day care centers (Töölö and Vallila) in Helsinki were measured with continuously recording personal exposure monitors. In Vallila, the median CO exposure of children from homes with gas stoves was 2.0 mg m−3, and with electric stoves, 0.9 mg m−3. In Töölö, the corresponding values were 1.9 and 1.0 mg m−3, respectively. The national ambient air quality guidelines for CO in Finland were exceeded in a few percent of the exposure measurements. The results were compared to fixed-site ambient air monitoring data and related to the presence of town-gas fired stoves in the children's homes. The results show that fixed-site ambient air monitors are of little value in predicting personal exposures of children or even their relative differences between areas. They also show that town-gas fired stoves may have a profound effect on the CO exposures of the children.
Regression analysis of daily mortality in Los Angeles County shows that there is a significant association between community carbon monoxide concentrations and mortality. Cyclic variation and maximum temperature were the main contributors. No association was demonstrated between oxidant and mortality.
This study investigates the ability of fixed location ambient air quality monitoring stations to represent personal environmental exposures to carbon monoxide (CO) accurately. The relationship between residential location, commuting transportation mode, employment location, and time weighted average human exposure to CO in the metropolitan area was also explored. Personal exposure was measured by equipping 66 nonsmoking volunteers in the Boston area with portable CO samplers which employ an electrochemical sensing method. Measurements at six fixed monitoring stations operated by the Massachusetts Bureau of Air Quality control underestimated mean 1 hour personal exposure by a factor of 1.3 to 2.1. However, alveolar air samples showed no significant increase in blood carboxyhemoglobin (COHb) levels due to commuting exposure since only 1% of the commuting exposures approached the national ambient air quality standard (NAAQS) of 35 ppm for 1 hour. The underestimation of personal exposure by fixed stations is of public health concern in those cities where violations of the 1 hour NAAQS have been reported. Fixed location measurements were representative of 8 hour average population exposure. Mode and route of travel were the only factors influencing commuting exposure to CO. Total travel by automobile resulted in a mean CO exposure nearly twice that of rail mass transit and approximately 1.6 times that of split mode commuting. These results indicate that the most effective strategies for reducing both 1 hour and 8 hour exposures to CO are those requiring automobile emission control, system traffic flow improvement, and those designed to decrease traffic volumes.
We combined field and laboratory experimentation to evaluate the effects of nitrogen dioxide in a panel of Los Angeles area residents with chronic respiratory illness, 15 men and 11 women aged 47 to 69. All had heavy smoking history, chronic symptoms, and low FEV1; some also had low FVC. During the fall-winter high-NO2 season, they monitored themselves for 2-wk periods using spirometers in the home, passive NO2 sampling badges, and diaries to record time and activity patterns and clinical status. In the middle of each self-monitoring week they were exposed in a chamber, once to clean air and once to 0.3 ppm NO2. Chamber exposures were double blind, lasted 4 h, and included four 7-min exercise sessions with average ventilation rates near 25 L/min. Symptom reports and hourly forced expiratory function tests showed no statistically significant differences between clean air and NO2 chamber exposures, although peak flow showed a approximately 3% loss with NO2 relative to clean air during the first 2 h of exposure only (p = 0.056). No significant overall differences were found between field self-measurements and measurements of lung function in the chamber or between field measurements in clean air and NO2 exposure weeks. Field data showed that group average lung function and symptom levels were worse in the morning than later in the day (p < 0.005) but otherwise were stable over 2 wk. Even though most subjects smoked and stayed indoors 80 to 90% of the time, personal NO2 exposures correlated significantly with outdoor NO2 concentrations as reported by local monitoring stations.(ABSTRACT TRUNCATED AT 250 WORDS)
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.
A diary study on a random sample of 625 Swiss children aged 0 to 5 yr was conducted in two cities in Switzerland to investigate the association between air pollution and respiratory symptoms. Total suspended particulates (TSP), SO2 and NO2 were measured by city monitor. In addition, passive samplers inside and outside the home measured NO2 concentration during the 6 wk each child was on the diary. Diaries were filled out by parents, and 20% were validated with the attending pediatrician's case notes. Incidence and duration of symptom episodes were examined separately. The study included any episode, episodes of coughing without runny nose, upper respiratory episodes, and episodes of breathing difficulty. In regressions using 6-wk average pollution that controlled for medical history, NO2 measured outdoors but not indoors was associated with the duration of any symptom. Total suspended particulates were a more significant predictor of duration of any symptom than NO2. The 6-wk average TSP was significantly associated with incidence of coughing episodes and marginally significant as a predictor of upper respiratory episodes. Previous day's TSP was a significant predictor of incidence of upper respiratory symptoms. Annual average of NO2 was associated with the duration of any episode and of upper respiratory episodes. We conclude that the incidence and duration of respiratory symptom episodes are likely associated with particulate concentrations and duration may be associated with NO2.
Several approaches can be taken to estimate or classify total personal exposures to air pollutants. While personal exposure monitoring (PEM) provides the most direct measurements, it is usually not practical for extended time periods or large populations. This paper describes the use of indirect approaches to estimate total personal exposure for NO2 and particulate matter (PM), summarizes the distributions of these estimates, and compares the effectiveness of these estimates with microenvironmental concentrations for evaluating effects on respiratory function and symptoms. Pollutant concentrations were measured at several indoor and outdoor locations for over 400 households participating in an epidemiological study in Tucson, Arizona. Central site monitoring data were significantly correlated with samples collected directly outside homes, but the former usually had higher pollutant concentrations. Integrated indices of daily total personal exposure were calculated using micro-environmental (ME) measurements or estimates and time-budget diary information. Peak expiratory flow rates (PEFR) were measured for up to four times a day during two-week study periods. In thirty children (ages 6-15 years) with current diagnosed asthma, a significant reduction in PEFR was associated with NO2 levels measured outside of their homes. Additional decrements of morning PEFR were found in those children sleeping in bedrooms with higher measured NO2 levels. Morning and noon PEFR decrements were also linked to higher morning NO2 levels that were measured at central monitoring stations. Effects of PM were also found, but were limited to morning PEFR. No effects were found in non-asthmatic children. The relationship of PEFR to the calculated indices of daily average total exposure were weaker than to the microenvironment concentrations. This suggests that diary and ME monitoring data need to yield better time resolution in order to incorporate short-term average exposures to higher concentrations into the exposure indices and into the analysis of within day health responses.
Several studies indicated that short-term increases in concentration of pollution in the atmosphere of a town may result in increased mortality in the days following the episode. To evaluate this relationship we analyzed data on daily mortality in Cracow, Poland, in the period 1977-1989 and data on daily concentrations of suspended particulates (PM 20) and sulfur dioxide (SO2) in the town area. This analysis was restricted to winter months. In 1167 winter days, an average of 18.4 deaths of Cracow residents occurred daily. PM 20 concentration exceeded 300 micrograms/m3 in 21%, and SO2 exceeded 200 micrograms/m3 in 19% of those days. The correlation coefficient of the daily number of deaths with the air pollution in the 24 hours preceding the day of death was 0.093 (p < 0.01) for PM 20, and was 0.141 (p < 0.001) for SO2. Similar correlations were found for air pollution levels in the four days preceding death, and the correlation decreased for earlier days. The effects were more pronounced in people over 65 years of age than in those younger, especially in males. After adjustment for SO2 levels, PM 20 had no additional effect on mortality. It was estimated that with an increase of SO2 concentration of 100 micrograms/m3, the daily number of deaths due to respiratory system diseases increased by 19% and deaths due to circulatory system diseases by 10%.
The authors assessed the relation between sulfur dioxide and other air pollutants (black smoke, carbon monoxide, nitrogen dioxide, and ozone) and daily emergency room admissions for chronic obstructive pulmonary disease in Barcelona, Spain, during 1985-1986. Barcelona is a Mediterranean city of 1.7 million inhabitants that has air pollution levels lower than standard values. A weak but statistically significant association between emergency room admissions and levels of sulfur dioxide, black smoke, and carbon monoxide was observed. Daily emergency room admissions for chronic obstructive pulmonary disease increased by 0.02 and 0.01 for each microgram of sulfur dioxide and black smoke per cubic meter, respectively, and 0.11 for each milligram of carbon monoxide per cubic meter, after adjusting for meteorologic and temporal variables. Similar estimations were obtained after controlling for the autocorrelation effect by means of time series analysis. In addition, when the data were stratified by season, the effects remained in summer. This strengthened the conclusion that the relation observed in winter, spring, and throughout the study period was indeed real. After truncating the data according to sulfur dioxide or black smoke levels, the authors still found effects for these pollutants at levels below the air quality guideline of 100 micrograms/m3 established by the World Health Organization. The consistency of these results with other recent toxicologic and epidemiologic observations suggest that current air pollution standards do not totally protect public health with a margin of safety in specific places.
We report results of a multiple regression analysis examining associations between aggregate daily mortality counts and environmental variables in Los Angeles County, California for the period 1970 to 1979. Mortality variable included total deaths not due to accidents and violence (M), deaths due to cardiovascular causes (CV), and deaths due to respiratory causes (Resp). The environmental variables included five pollutants averaged over Los Angeles County--total oxidants (Ox), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and KM (a measure of particulate optical reflectance). Also included were three metereological variables measured at the Los Angeles International Airport--temperature (Temp), relative humidity (RH), and extinction coefficient (Bext), the latter estimated from noontime visual range. To reduce the possibility of spurious correlations arising from the shared seasonal cycles of mortality and environmental variables, seasonal cycles were removed from the data by applying a high-pass filter. Cross-correlation functions were examined to determine the lag structure of the data prior to specifying and fitting the multiple regression models relating mortality and the environmental variables. The results demonstrated significant associations of M (or CV) with Ox at lag 1, temperature, and NO2, CO, or KM. Each of the latter three variables were strongly associated with daily mortality but also were highly correlated with one another in the high-frequency band, making it impossible to uniquely estimate their separate relationships to mortality. The results of this study show that small but significant associations exist in Los Angeles County between daily mortality and three separate environmental factors: temperature, primary motor vehicle-related pollutants (e.g., CO, KM, NO2), and photochemical oxidants.
We evaluated alveolar carbon monoxide (CO) levels of 122 male, adult hockey players active in recreational leagues of the Quebec City region (Canada), before and after 10 weekly 90-minute games in 10 different rinks. We also determined exposure by quantifying the average CO level in the rink during the games. Other variables documented included age, pulmonary function, aerobic capacity, and smoking status. Environmental concentrations varied from 1.6 to 131.5 parts per million (ppm). We examined the absorption/exposure relationship using a simple linear regression model. In low CO exposure levels, physical exercise lowered the alveolar CO concentration. However, we noted that for each 10 ppm of CO in the ambient air, the players had adsorbed enough CO to raise their carboxyhemoglobin (COHb) levels by 1 percent. This relationship was true both for smokers and non-smokers. We suggest that an average environmental concentration of 20 ppm of CO for the duration of a hockey game (90 minutes) should be reference limit not to be exceeded in indoor skating rinks.
In 1985, 362 primary schoolchildren and their 319 mothers were surveyed in Hong Kong to study the possible relationship of air pollution to respiratory illnesses. Using nitrogen dioxide (NO2) measured by personal samplers as a measure of air pollution, the study aimed to identify the major sources of NO2 in the indoor environment and see whether its increased presence was associated with respiratory symptoms. The levels of NO2 among the mothers was found to increase by 21% if dust exposure was reported from the workplace, 18% if they used such cooking fuels as liquid petroleum gas or kerosene, 11% when kitchens did not have ventilating fans, and 10% when incense was burned at home. In terms of respiratory symptoms, an increase in NO2 levels of 19% was reported among those with allergic rhinitis and 18% among those with chronic cough. The levels of NO2 among children were correlated with levels measured in classrooms, all of which had opened windows so that the NO2 came from outdoors. No association was found between children's NO2 levels and respiratory symptoms. With the exception of smoking by the father and the children's NO2 levels, no association was found between smoking at home and NO2 levels.
The weekly changes in ambient sulfur dioxide, nitrogen dioxide, and temperature were compared with the figures for respiratory infection in children and adults and for absenteeism from day-care centers (DCC), schools, and workplaces during a 1-year period in Helsinki. The annual average level of sulfur dioxide was 21 micrograms/m3 and of nitrogen dioxide 47 micrograms/m3; the average temperature was +3.1 degrees C. The levels of these pollutants and the temperature were significantly correlated with the number of upper respiratory infections reported from health centers. Low temperature also correlated with increased frequency of acute tonsillitis, of lower respiratory tract infection among DCC children, and of absenteeism from day-care centers, schools and workplaces. Furthermore, a significant association was found between levels of sulfur dioxide and absenteeism. After statistical standardization for temperature, no other correlations were observed apart from that between high levels of sulfur dioxide and numbers of upper respiratory tract infections diagnosed at health centers (P = 0.04). When the concentrations of sulfur dioxide were above the mean, the frequency of the upper respiratory tract infections was 15% higher than that during the periods of low concentration. The relative importance of the effects of low-level air pollution and low temperature on health is difficult to assess.
The effect of air pollution on lung function in children and youths ages 6-24 years was examined, after controlling for age, height, race, sex, body mass, cigarette smoking, and respiratory symptoms. Forced vital capacity (FVC), forced expiratory volume at 1 sec (FEV1), and peak expiratory flow all showed statistically significant (P less than 0.05) negative correlations with annual concentrations of total suspended particulates (TSP), nitrogen dioxide, and ozone. The ozone and NO2 relationships were highly significant. The TSP relationship was less significant. No relationship was found with sulfur dioxide. The relationships held whether or not children with respiratory conditions, or smokers were included. Demographic and geographic variables had little or no impact on the pollution relationships, which also held when only persons still residing in their state of birth were considered. Essentially identical relationships were found using pollution averaged over 2 years. The relationships held across most NO2 concentrations, but were only apparent at high particulate and ozone concentrations.