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Indoor air quality in the primary school of China—results from CIEHS 2018 study
Abstract
Indoor air quality ((IAQ) in classrooms was associated with the daily exposure of school-age children who are particularly vulnerable to air pollutants exposure, while few data exist to evaluate classroom indoor air quality nationwide in China. The subsample of the CIEHS 2018 study was performed in 66 classrooms of 22 primary schools nationwide in China. Temperature, relative humidity, PM2.5, PM10, CO2, CO, formaldehyde concentrations, bacteria and fungi were detected in all classrooms by using the instruments that meet the specified accuracy. The ratios of indoor to outdoor (I/O) of PM2.5 were calculated in each classroom to identify whether the indoor environment the pollutants comes from outdoors. The indoor PM2.5, PM10, CO, HCHO, bacteria and fungi GM concentration are 47.40 μg/m³, 72.91 μg/m³, 0.37 mg/m³, 0.02 mg/m³, 347.51 CFU/m³ and 362.76 CFU/m³, respectively. We observed that there were 66.5%, 52.6%, 22.4%, 1.8%, and 9.6% of the classrooms that exceeded the guideline values of PM2.5, PM10, CO2, HCHO, and bacteria, respectively. It should be attention that all of the classroom's PM2.5 concentrations in Shijiazhuang and Nanning, PM10 concentrations in Nanning, CO2 concentration in Lanzhou were exceeded the suggested values. Bacteria contamination in Shijiazhuang's classrooms is also serious. All classroom CO concentrations meet the requirement. The results indicated that classroom indoor PM2.5 was significantly positively correlated with indoor PM10 and CO2, while was negative correlated with temperature, CO, and fungi. Our results suggest that indoor air pollution in classrooms was a severe problem in Chinese primary schools. It is necessary to strengthen ventilation in the classroom to improve indoor air quality. What's more, a healthy learning environment should be created for primary school students.
... Some indoor environments are particularly crucial for safety concerns. Besides healthcare structures and hospices, schools and educational institutes, usually crowded with children, represent a fundamental issue of ensuring a safe living space, as children and teenagers too, are considered at risk category subjects [28][29][30] . The same may be held for daily workers, to ensure a healthy indoor living and reduce job-related injuries. ...
... Selection of indoor spaces and microenvironment assessment. Major eligibility criteria for spaces selection in our study referred to previously published reports in order to assess a quite constant microclimate in our indoor environments [21][22][23][24][25][26][27][28][29][30][31][32][33]35 , so to significantly reduce the impact of outliers, bias and confounders in our collected data. To extend our investigation to the widest typology of indoor spaces undergoing our photocatalyst technology, we selected: (a) four different school classrooms (data collection from May 25th 2021 to June 7th 2021); (b) a farm showroom (data collection from April 14th 2021 to June 14th 2021); (c) two different housing farm boxes (job containers) (data collection from April 29th 2021 to May 13th 2021); (d) a laundering depot in a laundry (data collection from June 11th 2021 to June 16th 2021); (e) a phone shop (data collection from September 16th 2021 to November 12th 2021). ...
TiO2–Ag doped nanoparticulate (TiO2–Ag–NP) adhesive photocatalytic films were used to assess the ability in dropping down the burden of indoor microbial particles. The application of an easy-to use photocatalytic adhesive film to cleanse indoor living spaces from microbial pollution, represents a novelty in the field of photocatalytic devices. Reduction was attained by photocatalysis in selected spaces, usually with overcrowding (≥ 3 individuals) in the common working daily hours, and upon indoor microclimate monitoring. TiO2–Ag doped nanoparticulate (TiO2–Ag–NP) adhesive photocatalytic films were applied within five types of living spaces, including schools and job places. The microbial pollution was assessed at time 0 (far from routine clean, ≥ 9 h) and throughout 2–4 weeks following the photocatalyst application by relative light unit (RLU) luminometry and microbial indirect assessment (colony forming units per cubic meter, CFU/m3). TiO2–Ag–NP photocatalyst reduced RLU and CFU/m3 by rates higher than 70% leading to RLU ≤ 20 and microbial presence ≤ 35 CFU/m3. The described TiO2–Ag–NP is able to reduce microbial pollution to the lowest RLU threshold (≤ 20) within 60 min in open daylight in a standardized test room of 100 m2. The correlation between RLU and CFU/m3 was positive (r = 0.5545, p < 0.05), assessing that the microbial reduction of indoor areas by the TiO2–Ag–NP adhesive film was real. Titania photocatalysts represent promising tools to ensure air cleaning and sanitization in living indoor microclimates with a low cost, feasible and straightforward approach. This approach represents an easy to handle, cost effective, feasible and efficacious approach to reduce microbial pollution in indoor spaces, by simply attaching a TiO2–Ag–NP adhesive film on the wall.
... Some indoor environments are particularly crucial for safety concerns. Besides healthcare structures and hospices, schools and educational institutes, usually crowded with children, represent a fundamental issue of ensuring a safe living space, as children and teenagers too, are considered at risk category subjects [28][29][30] . The same may be held for daily workers, to ensure a healthy indoor living and reduce job-related injuries. ...
... Selection of indoor spaces and microenvironment assessment. Major eligibility criteria for spaces selection in our study referred to previously published reports in order to assess a quite constant microclimate in our indoor environments [21][22][23][24][25][26][27][28][29][30][31][32][33]35 , so to significantly reduce the impact of outliers, bias and confounders in our collected data. To extend our investigation to the widest typology of indoor spaces undergoing our photocatalyst technology, we selected: (a) four different school classrooms (data collection from May 25th 2021 to June 7th 2021); (b) a farm showroom (data collection from April 14th 2021 to June 14th 2021); (c) two different housing farm boxes (job containers) (data collection from April 29th 2021 to May 13th 2021); (d) a laundering depot in a laundry (data collection from June 11th 2021 to June 16th 2021); (e) a phone shop (data collection from September 16th 2021 to November 12th 2021). ...
TiO2–Ag doped nanoparticulate (TiO2–Ag–NP) adhesive photocatalytic films were used to assess the ability in dropping down the burden of indoor microbial particles. The application of an easy-to use photocatalytic adhesive film to cleanse indoor living spaces from microbial pollution, represents a novelty in the field of photocatalytic devices. Reduction was attained by photocatalysis in selected spaces, usually with overcrowding (≥ 3 individuals) in the common working daily hours, and upon indoor microclimate monitoring. TiO2–Ag doped nanoparticulate (TiO2–Ag–NP) adhesive photocatalytic films were applied within five types of living spaces, including schools and job places. The microbial pollution was assessed at time 0 (far from routine clean, ≥ 9 h) and throughout 2–4 weeks following the photocatalyst application by relative light unit (RLU) luminometry and microbial indirect assessment (colony forming units per cubic meter, CFU/m3). TiO2–Ag–NP photocatalyst reduced RLU and CFU/m3 by rates higher than 70% leading to RLU ≤ 20 and microbial presence ≤ 35 CFU/m3. The described TiO2–Ag–NP is able to reduce microbial pollution to the lowest RLU threshold (≤ 20) within 60 min in open daylight in a standardized test room of 100 m2. The correlation between RLU and CFU/m3 was positive (r = 0.5545, p < 0.05), assessing that the microbial reduction of indoor areas by the TiO2–Ag–NP adhesive film was real. Titania photocatalysts represent promising tools to ensure air cleaning and sanitization in living indoor microclimates with a low cost, feasible and straightforward approach. This approach represents an easy to handle, cost effective, feasible and efficacious approach to reduce microbial pollution in indoor spaces, by simply attaching a TiO2–Ag–NP adhesive film on the wall.
... Particularly, students are considered more vulnerable to the poor IEQ since they spend a noteworthy part of their time in the scholastic environment (Arcega-Cabrera et al., 2018;Ferguson & Solo-Gabriele, 2016;Iglesias-González et al., 2020;Ma et al., 2019;Turunen et al., 2014). Therefore, the educational buildings should provide a secure, healthy, and comfortable indoor environment for students (Bortolini & Forcada, 2021;Zhu et al., 2021;Zinzi et al., 2021). This study is motivated by the main concern of poor IEQ in the campus buildings, which can lead to health issues, high virus transmission rates, and reductions in learning performance in the long term (Annesi-Maesano et al., 2013;Daisey et al., 2003;Turunen et al., 2014;Veenhoven, 1989;Zhu et al., 2021). ...
... Therefore, the educational buildings should provide a secure, healthy, and comfortable indoor environment for students (Bortolini & Forcada, 2021;Zhu et al., 2021;Zinzi et al., 2021). This study is motivated by the main concern of poor IEQ in the campus buildings, which can lead to health issues, high virus transmission rates, and reductions in learning performance in the long term (Annesi-Maesano et al., 2013;Daisey et al., 2003;Turunen et al., 2014;Veenhoven, 1989;Zhu et al., 2021). ...
The level of generated plastic waste has awash over a billion metric tonnes of this waste into our environment. If an effective long-lasting solution to this impending disaster is not provided through recycling, reengineering, and conversion of this waste to resourceful materials. Then sustainability and conservation of natural non-replenishable materials will be severely threatened. The aims to avert the impending consequences of this disaster and conserve natural materials have given rise to a sustainable future in the production of low carbon embedded construction materials. Under these circumstances, this study, therefore, presents the strengths and durability of waste plastic bricks (WPB) produced from blending scrap PET plastics and foundry sand. The WPB masonry bricks were produced using ratios of 10:90, 20: 80, and 30: 70 to the combined dry mass of PET and sand. Series of compressive strength tests, modulus of rupture (MOR) tests, apparent porosity tests, water absorption tests, salt-resistance tests, ultrasonic pulse velocity, and scanning electron microscopy (SEM) tests were conducted to investigate the strength and durability of the WPB in conformance with the South African National Standard (SANS 227) for individual load-bearing masonry face brick unit. Compared to the clay bricks with 18 MPa what of strength, the test result revealed that the WPB rendered an average compressive strength of 35.2 MPa. Furthermore, the test result showed that the WPB recorded significant strength resistance under tension compared to the clay brick due to the ductility properties of scrap plastic waste. Also, the acid effects were significantly resisted on the surface WPBs due to the hydrophobic property of the PET- waste. The stiffness of the clay bricks portrayed brittle response, whereas WPBs benefited with high ductility properties, therefore, revealed a great proportionality between the dynamic modulus and ultrasonic pulse velocity (UPV) with a coefficient of determination (R2) of 90%.
... Particularly, students are considered more vulnerable to the poor IEQ since they spend a noteworthy part of their time in the scholastic environment (Arcega-Cabrera et al., 2018;Ferguson & Solo-Gabriele, 2016;Iglesias-González et al., 2020;Ma et al., 2019;Turunen et al., 2014). Therefore, the educational buildings should provide a secure, healthy, and comfortable indoor environment for students (Bortolini & Forcada, 2021;Zhu et al., 2021;Zinzi et al., 2021). This study is motivated by the main concern of poor IEQ in the campus buildings, which can lead to health issues, high virus transmission rates, and reductions in learning performance in the long term (Annesi-Maesano et al., 2013;Daisey et al., 2003;Turunen et al., 2014;Veenhoven, 1989;Zhu et al., 2021). ...
... Therefore, the educational buildings should provide a secure, healthy, and comfortable indoor environment for students (Bortolini & Forcada, 2021;Zhu et al., 2021;Zinzi et al., 2021). This study is motivated by the main concern of poor IEQ in the campus buildings, which can lead to health issues, high virus transmission rates, and reductions in learning performance in the long term (Annesi-Maesano et al., 2013;Daisey et al., 2003;Turunen et al., 2014;Veenhoven, 1989;Zhu et al., 2021). ...
Educational buildings should provide a secure, healthy, and comfortable indoor environment for students since they spend a noteworthy part of their time inside. The present study aims to identify and assess the key indicators related to the light and air quality of a campus classroom, which contributes to the health of students. The indicators are chosen from an existing green rating tool, the WELL Building Standard (WBS). The research methodology consists of three main phases; indicator selection, impact assessment, and validation process. The engagement of stakeholders was taken into the account in the entire research framework. The research findings showed that there is a considerable gap among the acceptable range of indoor air and the light quality of the classroom. This led to verifying various health issues among the students, including dryness and irritation of the skin and eyes, and consequently increased their dissatisfaction rate. The study provides some significant insights based on the obtained results, highlighting the importance of incorporating student health and wellness into educational building design and operations, including visual comfort and indoor air quality conditions, which are often worse than the stipulations in standards. Abstract Introduction
... Guidelines and reference values for a number of indoor pollutants have been established by the World Health Organization (WHO) (19) and the U.S. Environmental Protection Agency (USEPA) (20), but indoor monitoring and enforcement are uncommon. Often, PM 2.5 and CO 2 levels in classrooms exceed reference values, especially in less developed regions such as central Europe (21,22) and China (23). In the U.S., attainment with reference levels has been mixed, e.g., 16 city schools in mid-Atlantic cities mostly met WHO guidelines for PM 2.5 (25 μg/ m 3 daily average, the interim target 4) (19, 24) and the ASHRAE guidance for CO 2 (1,000 ppm) (25), while pollutant levels tended to be higher in schools in the Midwest (26, 27). ...
Introduction
Many school buildings have inadequate ventilation, rudimentary if any air filtration, and aging and poorly maintained mechanical systems, all of which can lead to poor indoor air quality (IAQ). These issues are especially acute in environmental justice (EJ) communities where schools are located in polluted areas. This community-based participatory research examines how IAQ in naturally ventilated school buildings is affected by the use of air purifiers, air change rates, outdoor pollution levels, and teacher and staff behavior.
Methods
IAQ assessments were performed at two schools in Detroit, Michigan, which included building walk-through inspections and continuous indoor and outdoor measurements of black carbon (BC), particulate matter (PM 10 and PM 2.5 ), carbon dioxide (CO 2 ), air change rates (ACRs), temperature, humidity, and sound pressure levels. Air purifiers with usage monitors were then installed, and the IAQ assessments were repeated. Teachers were surveyed before and after purifier deployment.
Results
At baseline, classrooms had low ACRs (0.58–1.38 h ⁻¹ ), moderate PM 2.5 levels (2.8–8.9 μg/m ³ ), highly variable PM 10 concentrations (4.7–37.5 μg/m ³ ), and elevated BC levels (0.3–0.7 μg/m ³ ), reflecting emissions from local traffic, industry and other sources. The installation and use of purifiers reduced pollutant levels and the overall performance matched the predictions of a single compartment model. However, daily reductions varied widely among classrooms, reflecting differences in teacher behavior regarding the frequency of opening windows and the operation of purifiers, including differences in purifier fan speed settings and whether purifiers were used at night. Survey responses indicated that many teachers were aware of IAQ problems. The higher rates reported for health symptoms and dissatisfaction at one school may have lowered the teachers’ tolerance to noise and reduced purifier use.
Discussion
The study helps explain the variation reported in prior studies using purifiers, and it reinforces the need to monitor IAQ and purifier use, use enhanced filtration and increase ventilation, and engage with teachers and school staff to support and maintain IAQ programs in schools.
... Because not all organizations see CO2 as a pollutant, there is no clear indoor standard. On the other hand, Zhu et al. (2021) reported that PM and CO2 pollution in indoor environments during teaching hours, especially in primary schools, is a serious problem. According to the opinions on CO2 presence and concentration stated in the studies, we can be sure that the values observed in this study have a negative effect on IAQ. ...
This is the first study to evaluate the indoor air quality of markets using the “Indoor Environmental Index (IEI)”. In the study, carbon dioxide (CO2), relative humidity, temperature, particulate matter, and total volatile organic compounds were measured as indoor air quality parameters in four different markets in Istanbul during the COVID-19 pandemic. Data were analyzed and evaluated using IBM SPSS Statistics 22 program. While CO2, Paticulate matters (PM2.5, PM10), humidity, and temperature had a statistically significant difference in different markets, no statistically significant difference was found for NO2 and total volatile organic compounds (p>0.05). Considering the different hours in a day, it was determined that there was a statistically significant difference for all parameters. The highest and strongest correlation between the parameters was found between PM2.5 and PM10 (r=0.703, p<0.01). The IEI values for 4 different markets in different time intervals in a day were found as 6.862, 6.775, 8.816, and 6.244, respectively. The highest and lowest Indoor Environmental Index values were calculated in market 2 (7.525) and market 4 (4.936), respectively. Indoor air quality parameters had an impact on the IEI results as they affected the pollution index and the discomfort index. As a result of the study, it was seen that the density of customers and products, the size of the closed area of the markets, and the capacity of ventilation equipment affect the indoor air quality. All these results were evaluated and suggestions were made about the visit times to the markets.
... The results showed that there were 66.5%, 52.6%, 22.4%, 1.8%, and 9.6% of the classrooms exceeded the guideline values of PM 2.5 , PM 10 , CO 2 , HCHO, and bacteria, respectively. Indoor air pollution in classrooms was a severe problem in Chinese primary schools [34]. ...
The air quality in classrooms significantly impacts school children’s health and learning performance. It has been reported worldwide that classroom air quality does not meet the required standard and actions are pledged for improvement. However, it poses a challenge for decision-making in terms of prioritising taking-up measures. The aim of this study is to propose a method of identifying the action measures for improving classroom air quality and prioritising them. Case studies in the UK and China were conducted, and the key measures were identified through literature studies, open-ended questionnaire surveys, and workshop discussions, which are classified into three categories: B1, policy; B2, technology; and B3, information sharing. The analytical hierarchy process (AHP) is applied in the prioritisation of the action measures. A total of 138 teachers and parents from China and the UK participated in this case study. The genetic algorithm-optimised Hadamard product (GAOHP) method is applied to justify the consistency ratio (CR) within the required threshold value in order to ensure the consistency of the subjective perception and the accuracy of comparative weights. The results show that item B2, technology, is the most desired measure by both Chinese and British parents and teachers, despite the deviation from the optimal choice in China and the UK. Among the proposed action measures, the UK respondents strongly expected air purifiers with natural ventilation as opposed to their Chinese counterparts preferring to share the real-time status of classroom air quality. Our work will provide strong support for the subsequent selection of indoor air quality improvement strategies for schools.
... Many studies that have been carried out in numerous places around the world indicate correlations between exposure to air pollution and negative health effects (Park et al., 2020;Bukłaha et al., 2022;Sowiak et al., 2018). Air quality has a significant impact on human health and life expectancy (Zhu et al., 2021). Frequently staying in small indoor spaces is associated with the appearance of various diseases (Gładysz, et Air fungal pollution is responsible for 30% of all diseases caused by poor air quality. ...
... The examination outcomes indicate that, like discoveries about macro fibres of predetermined lengths [71], including hybrid-length macro fibres can enhance concrete beams' flexural strength and toughness. Additionally, this enhancement becomes more pronounced as the fibre volume ratio increases [64,70]. ...
The rapid growth of the wind energy industry has resulted in a significant increase in Wind Turbine Blade (WTB) waste, posing challenges for recycling due to the composite materials used in their construction. Several proposed techniques, including mechanical, thermal, and chemical processes, have been considered for wind-blade recycling, but determining the most effective approach remains a critical issue. This study presents the first comprehensive systematic review of available wind-blade recycling processes, evaluating their economic, technical, and environmental performance. Additionally, we consider the physical and mechanical properties of the recycled materials, which can aid in identifying potential markets for these materials. Among the various recycling technologies, microwave pyrolysis emerges as the most promising technique for recycling large quantities of WTB, despite some challenges and uncertainties surrounding its effectiveness and feasibility at an industrial scale. However, the optimal recycling technique for WTB will depend on multiple factors, including the blade material, the desired environmental impact, and the economic feasibility of the process. Based on this review, mechanical recycling appears to be more energy-efficient, while the fluidised bed recycling process demonstrates a lower primary energy demand, global warming potential, and power consumption. These findings provide valuable guidance for decision-makers in the wind energy industry to develop effective waste management strategies and plans for sustainable wind energy development. Addressing WTB waste and implementing efficient recycling techniques will be critical in mitigating environmental impacts and promoting sustainability in the renewable energy sector as the wind energy industry grows.
... The type, intensity, duration, and frequency of indoor activities are the main factors that determine indoor-generated pollutants [16,136]. Many worldwide studies have shown that PM pollution in school classrooms exceeds the WHO requirements [137][138][139][140]. Resuspension of residential dust particles due to human activity increases indoor particle concentrations [141,142]. ...
Particulate matter (PM) resuspension from indoor surfaces is one of the leading causes of occupant exposure to PM. It has been recognized as a main source of indoor air pollution by many field studies. This review article explores the mechanisms and effects of single and multiple influential factors on PM resuspension, distribution characteristics, spatial and temporal PM distribution characteristics and interactions of human activities and mitigation measures. A roadmap is proposed to provide a strong basis for subsequent research into the dynamic characteristics of PM resuspension. The synthesis of existing literature suggests that the mechanism behind the opposite effect caused by multiple influential factors deserves further exploration. Microscopic simulations of motion over short periods and richer activity features based on various scenarios are needed to get more accurate results. More advanced strategies should be considered to change the control process and enhance the efficiency of the purification devices. Collaboration between multiple disciplines is required to get the complete picture of PM resuspension.
... Ultrafine particles affect most urban students (Zhu et al., 2021). Because studentsbreathe more air per unit of body weight & have growing tissues & organs, therefore more vulnerable to air contaminants than adults (Bluyssen et Since the theoretical link between these techniques (Qualitative & Quantitative approach) & the relevant circumstances has not yet been studied, this is a promising study field. ...
Educational Institute indoor environment, where students spend a lot of time, is a major
problem because of how vulnerable & sensitive they are to exposure to air pollution. The
rising prevalence of asthma & respiratory disease among students, who spend a substantial
portion of their lives on educational institutes’ grounds, has contributed to the growing
interest in indoor air quality (IAQ) of educational buildings. The designated institutions are
located in metropolitan settings. As a result of high occupancy inadequate ventilation,
building structure, seasonal variations as well as elevated levels of particulate matter (PM) &
total volatile organic compounds (TVOC), educational Institutes in Delhi had generally poor
indoor air quality, as measured by air quality measurements. Educational Institutes near urban
areas are substantially more affected by the dispersion of pollutants than educational
Institutes in rural areas & other adjacent environments. Therefore, management suited to the
characteristics of educational Institute buildings is required. In conclusion, the review
suggests that qualitative data could supplement the traditionally quantitative field of indoor
air quality. It is likely that multidisciplinary research will comprehensively explain
environmental health trends noticed in student by quantitative research. Provided
explanations are essential for managing environmental health of students, seasonal variations,
building structures & devising effective strategies for prevention, mitigation, &
communication.
Keywords: IAQ, Educational Institutes, Factors, Urban settings, Mitigation
... Indoor air quality has been debated at length in many recent studies focusing on schools [1], offices [2], residential areas [3] etc. The principal reason behind the aforesaid factor is greater human exposure to pollutants in an indoor environment than outdoor [4,5]. Usually, buildup of pollutants in an indoor environment is attributed to the insufficiently low ventilation rates (VRs) to save energy costs. ...
Keeping COVID-19 pandemic in perspective, good indoor air quality (IAQ) and adequate ventilation are imperative to minimize risk of virus spread, besides other poor IAQ related risks. Thus, present study is focused on evaluation and comparison of ventilation rates (VRs) in office buildings with different ventilation mechanisms. Two-season (summer and winter) data of indoor CO2 was collected, and VRs were calculated adopting three methods i.e., transient mass balance, steady-state and decay method, and were then input in system dynamics-based (SD) model for finding best method for the calculation of VRs. In the last part, simulations were used to calculate the optimum VRs to keep indoor CO2 levels below recommended limits. Results showed statistical difference (p < 0.05) of indoor CO2 among buildings and between seasons. Although better VRs were observed in mechanically ventilated offices, it is to be noted that windows in naturally ventilated offices were observed to be closed (to maintain thermal comfort) and thus naturally ventilated buildings were not operated as per design provisions. Moreover, transient mass balance method was found to be more accurate approach for VRs estimation. Furthermore, it was found that to limit indoor CO2 levels below 1100, 800 and 700 ppm, minimum VRs should be maintained as 10, 16 and 20 l/s/person respectively.
... Because not all organizations see CO 2 as a pollutant, there is no clear indoor standard. On the other hand,Zhu et al. (2021) reported that PM and CO 2 pollution in indoor environments during teaching hours, especially in primary schools, is a serious problem. According to the opinions on CO 2 presence and concentration stated in the studies, we can be sure that the values observed in this study have a positive correlation with temperature, supporting the hypothesis that the warm season will not stop COVID-19spreading. ...
This is the first study to evaluate the indoor air quality of markets using the “Indoor Environmental Index”. In the study, carbon dioxide (CO 2 ), relative humidity, temperature, particulate matter, and total volatile organic compounds were measured as indoor air quality parameters in four different markets in Istanbul during the COVID-19 pandemic. Data were analyzed and evaluated using IBM SPSS Statistics 22 program. While CO 2 , PM 2.5 , PM 10 , humidity, and temperature had a statistically significant difference in different markets, no statistically significant difference was found for NO 2 and total volatile organic compounds (p > 0.05). Considering the different hours in a day, it was determined that there was a statistically significant difference for all parameters. The highest and strongest correlation between the parameters was found between PM 2.5 and PM 10 (r = 0.703, p < 0.01). The IEI values for 4 different markets in different time intervals in a day were found as 6.862, 6.775, 8.816, and 6.244, respectively. The highest and lowest Indoor Environmental Index values were calculated in market2 (7,525) and market4 (4,936), respectively. Indoor air quality parameters had an impact on the IEI results as they affected the pollution index and the discomfort index. As a result of the study, it was seen that the density of customers and products, the size of the closed area of the markets, and the capacity of ventilation equipment affect the indoor air quality. All these results were evaluated and suggestions were made about the visit times to the markets.
... Indoor environmental contamination is a major concern because of its direct adverse health effects on humans [1]. Typically, people spend almost 90% of their time indoors, whether in their houses, dwellings, workplaces, or schools, where they can be constantly exposed to organic pollutants [2][3][4]. Accordingly, indoor environmental quality monitoring studies became a must for identifying the levels and sources of these pollutants indoors, enabling for their control [5,6]. Studies have reported that semivolatile organic compounds (SVOCs) are, in association with volatile organic compounds and particulate matter, the main source of indoor environmental-quality alteration [5][6][7]. ...
Indoor environmental exposure to pesticides has become one of the major concerns that might adversely affect human health and development. People spend most of their lifetime in enclosed indoor environments where they might inhale harmful toxic chemicals, such as pesticides, dispersed either in particulate or in a gas phase. In this study, an assessment of pesticide contamination in indoor environments was conducted. The study covered nine houses during one year, starting from February 2016 and ending in February 2017, in which both air and dust samples were assessed for their potential contamination with 50 pesticides. The results showed that all the assessed houses were contaminated by several pesticides, especially with the allethrin pesticide (detection frequency (DF) = 100%). The highest pesticide contamination was detected in the spring/summer season when it reached an average of around 185 ng g−1 and 186.4 ng sampler−1 in the collected dust and air samples, respectively. The potential contamination of pyrethroid insecticides within all the targeted samples revealed by this study stresses the importance of minimizing the use of such indoor treatments as part of the efficient prevention and control of human exposure to pesticides.
... Monitoring System" has been increased compared to the past years. An effective flowchart of the entire process to calculate the harmful gasses estimation has been shown in an effective manner [18]. In addition, in this flowchart it has been highlighted that first it is necessary to measure the CO Concentration and also need to calculate the sub-API of the CO. ...
IoT Based Air Pollution Monitoring System '' supports showing the quality of air in PPM over the LCD along with that on the web sheet therefore, as this can simply be scrutinized. In order to show the impact of “IoT based Air Quality Monitoring System '', flowcharts, graphs, digraphs and tables have been shown in an effective manner. According to the Statista, it has been estimated that “air quality monitoring IoT '' services along with products would be a significant economic value of 50 up to 60 billion US dollars by the year of 2025. In the present times the condition of air is not that good due to the increasing pollution rate in the past several years. In order to conduct this research work in an effective manner, a secondary data collection method has been taken and all the secondary data resources have been taken to conduct the research in a suitable manner. “IoT based Air Quality Monitoring system” has been suitably designed to quantity the mutual “air quality index” and it also helps in standardizing the results with “India’s Air Pollutant Index'' to suitably indicate the strictness of air superiority. The most harmful air pollutant gasses are NOx, LPG, CO2, NH3, Benzene, alcohol and benzene. In addition, with the help of this system, temperature along with humidity both can effectively be monitored. LPG gas has been suitably detected to use MQ135 and MQ6 sensors and this has been used for monitoring the air’s quality as it helps in detecting all these harmful elements. In this research work, it has been shown that focusing on “Triple Bottom Line '' theory can be effective as this theory helps in showing the ways through which environmental sustainability can be maintained easily. Keyword : IoT based Air Quality Monitoring system, India’s Air Pollutant Index, air quality monitoring IoT .
... There are other indoor environments of interest that could be further studied such as shopping centres, public buildings, indoor sports facilities and house environment, that are out of the scope of this work.3.3.1. School environmentDue to the observed health effects of increased CO 2 concentrations in enclosed spaces, several studies have been conducted in infant, primary, middle and high schools, where students spend several hours(Choe et al., 2022;Di Gilio et al., 2021;Gil-Baez et al., 2021;Mohamed et al., 2021;Zhu et al., 2021). A recent study reported that, in Spain, all the classrooms under investigation had short-term periods with CO 2 concentrations above all IAGVs (European, French, Portuguese and U.K IAGVs) with peaks of 3,284 ppm v for the infant and primary classrooms, and 5,366 ppm v for secondary and high schools(Becerra et al., 2020).Becerra et al. (2020) correlated these values with ventilation and occupancy rate, which was as low as 2.5 m 2 /student for secondary schools and high schools, resulting in high mean CO 2 concentrations. ...
In the developed world, individuals spend most of their time indoors. Poor Indoor Air Quality (IAQ) has a wide range of effects on human health. The burden of disease associated with indoor air accounts for millions of premature deaths related to exposure to Indoor Air Pollutants (IAPs). Among them, CO2 is the most common one, and is commonly used as a metric of IAQ. Indoor CO2 concentrations can be significantly higher than outdoors due to human metabolism and activities. Even in presence of ventilation, controlling the CO2 concentration below the Indoor Air Guideline Values (IAGVs) is a challenge, and many indoor environments including schools, offices and transportation exceed the recommended value of 1000 ppmv. This is often accompanied by high concentration of other pollutants, including bio-effluents such as viruses, and the importance of mitigating the transmission of airborne diseases has been highlighted by the COVID-19 pandemic. On the other hand, the relatively high CO2 concentration of indoor environments presents a thermodynamic advantage for direct air capture (DAC) in comparison to atmospheric CO2 concentration. This review aims to describe the issues associated with poor IAQ, and to demonstrate the potential of indoor CO2 DAC to purify indoor air while generating a renewable carbon stream that can replace conventional carbon sources as a building block for chemical production, contributing to the circular economy.
... ASHRAE Standard 2017 recommends levels of 1000ppm in the case of continuous exposure to CO 2 . Zhu et al. (2021) asserted that headaches, sore throat, and breathing difficulty such as asthma can result in occupational exposure to HCHO which is above 0.1ppm. The average air temperature (29.42°C); air velocity (0.98 m/s) and formaldehyde (0.87ppm) were beyond the acceptable and recommended threshold by ASHRAE and WHO. ...
Pharmaceutical factory buildings (PFBs) are expected to provide indoor environmental performance suitable to enhance workers’ well-being and productivity. This study examined the indoor environmental performance of PFBs in Nigeria towards modeling an enhanced worker’s well-being and productivity. Fourteen PFBs were purposively selected as investigation sites with a field survey conducted in Southwest Nigeria. Several types of equipment were used to obtain IAQ data (that is the air temperature, relative humidity, airflow velocity as well as the concentration of carbon dioxide (CO2 ), particulate matter, TVOC, and HCHO) along with subjective evaluation of the perception of the factory workers to obtain information on their working environment within the factories. Findings showed that average air temperature (29.42°C); air velocity (0.98 m/s) and formaldehyde (0.87ppm) were beyond the acceptable and recommended threshold by ASHRAE and WHO. However, the values obtained for CO2 , PM1.0 , PM2.5 , and PM10 were satisfactory. The study concludes by suggesting ways to improve the indoor environmental performance of PFBs and proposed a model to enhance the worker’s well-being and productivity.
... Relatively high PM concentration levels were observed in the MUF samples, compared to PTF samples. The PTF samples may undergo relatively high filtration due to central air conditioning and mechanical ventilation systems that effectively manage indoor air quality [52,53], as ventilation requirements are especially strict in South Korea. HCHO and TVOC are major air pollutants caused by human activity in indoor environments and by automobiles, trains, and subway trains in outdoor environments [13,54]. ...
Indoor microbes are readily transmitted among humans in indoor environments. Therefore, this study employed 16S rRNA gene and ITS amplicon profiling to investigate the dust-associated bacterial and fungal communities in six indoor facilities in Busan, South Korea. The collected samples were categorized into two groups: indoor multiple-use facilities (MUFs), including a public bathing facility, business office, and food court; and public transportation facilities (PTFs), including two subway stations and an airport. The bacterial diversity in the MUF samples was significantly higher than the fungal diversity (p < 0.05). However, no significant differences between bacterial and fungal diversity were observed in PTF samples (p > 0.05). Moreover, the abundances of certain microbial taxa varied, suggesting that the microbial community structure was primarily determined by the source environment. Gram-positive bacterial genera, such as Corynebacterium, Kocuria, and Staphylococcus—all of which originated in the natural environment—were relatively predominant in the MUF samples; the Aspergillus, Penicillium, and Malassezia genera, which are human commensal taxa, were relatively more predominant in the PTF samples. These results suggest that different microbial communities can be formed depending on the purpose of the indoor facility type, level of passenger traffic, and surrounding environment. The findings of this study may help researchers understand indoor microbial communities in multi-use and transportation facilities.
... Considerable number of studies in the literature have discussed the performance of mechanical ventilation in schools and the impact of inadequate ventilation rates on indoor air quality and specifically on indoor CO 2 concentrations. For instance, recent studies on primary schools in China showed that 22.4% of the examined schools exceeded the acceptable thresholds of CO 2 concentrations required by applicable standards and suggested increasing the mechanical ventilation rates to improve IAQ levels (Zhu et al. 2021). Another study, recently published (Cai et al. 2021), measured the CO 2 concentration for 33 classrooms of 21 schools in Beijing, China and found that the average mechanical ventilation rates in classrooms are about 4.7 L/s per person during class periods and recommended increasing the ventilation rate to maintain CO 2 concentrations below 1000 ppm. ...
The advantages of the demand control ventilation system (DCV) have been widely discussed in previous research studies. However, the literature has not addressed the benefits of DCV on controlling indoor CO2 concentration and minimizing cooling energy consumption for school buildings located in extremely hot climates. Therefore, this paper contributes to the development of DCV and mechanical ventilation systems through a comprehensive evaluation of these systems to maintain acceptable indoor air quality (IAQ) while minimizing cooling energy demands for school buildings located in the harsh hot climate of Saudi Arabia. The evaluation is based on a calibrated whole-building energy model and validated IAQ predictions using field data obtained from a school case study in Jeddah. The results of this research study confirm that hourly and sub-hourly monitoring of indoor CO2 concentration is required to ensure optimal design and operation of the ventilation systems in schools. In addition, the analyses indicate that a 13% increase in cooling energy end-use can result for any additional 0.1 students/m2 density increase in the classrooms. However, the energy penalties related to ventilation needs can be reduced by up to 25% using DCV instead of conventional mechanical ventilation systems for school buildings located in Saudi Arabia’s hot climate.
A few research studies about IEQ in university classrooms are reported from the hot arid climate despite the severity of this climate. In the reported study, the indoor conditions of university classrooms from a hot arid climate were evaluated considering the collective effect of the four main factors of IEQ, which are the thermal, visual, acoustic, and indoor air quality. The physical measurements were conducted for air temperature, globe temperature, relative humidity, air velocity, illuminance, sound pressure, and carbon dioxide levels. A questionnaire collected the students’ sensation, satisfaction, and preferences of the classrooms’ environments. The results reveal the sensitivity of the students’ environmental experience to the thermal and acoustic conditions. In light of this, a novel IEQ model that considers the air temperature and sound pressure level has been proposed. The model is statistically reliable as it has an RMSE of 0.002. Griffith’s method was used to calculate the comfort temperature at 23.0 ± 2.5 °C with a slope of 0.5/K. The findings of this study attempt to fill a gap in the knowledge regarding the IEQ conditions of university classrooms from the hot arid climate.
The present study portrays an association between particle-bound transition metals and children's health. The indoor air quality of the urban metropolitan city households was monitored for four PM sizes, namely PM1.0–2.5, PM0.50–1.0, PM0.25–0.50 and PM<0.25, in major seasons observed in the city; summer and winter. Further transition/heavy metals, viz. Cr, Cu, Fe, Mn, Ni, Pb and Zn, were analysed in PM1-2.5 samples. In order to evaluate the effect, health risk assessment was performed using mathematical and computational model for assessing dermal exposure and dose estimation (multiple path particle dosimetry model version3.0). The study principally targeted the children aged 2–15 years for the health risk assessment. According to the results, for the largest particle size i.e. PM1.0–2.5 the highest deposition was in the head region (49.1%) followed by pulmonary (43.6%) and tracheobronchial region (7.2%), whereas, for the smallest particle size i.e. PM<0.25 the highest deposition was obtained in the pulmonary region (73.0%) followed by the head (13.6%) and TB region (13.2%). Also, the most imperilled group of children with highest dose accumulation was found to be children aged 8–9 years for all particle sizes. Moreover, the dermal exposure dose as evaluated was found to be preeminent for Ni, Zn and Pb. Besides, seasonal variation gesticulated towards elevated concentrations in winter relative to the summer season. Altogether, the study will provide a conception to the researchers in the fields mounting season-specific guidelines and mitigation approaches. Conclusively, the study commends future work focussing on defining the effects of other chemical components on particles and associated transition metal composition along with proper extenuation of the same.
The focus of this chapter are inorganic gases like the air quality indicator carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2), ammonia (NH3), sulfur dioxide (SO2), and ozone (O3). They are presented individually in detail. In addition to a brief description of the chemical-physical characteristics and the use of the substance, an overview of main health risks and, in particular, references to further scientific literature are given. In the foreground, however, are extensive presentations of the occurrence of the substances in indoor air and in sedimented dust.
In this chapter, the particulate matter (PM), ultrafine particles, engineered nanoparticles, fibers like asbestos and man-made mineral fibers, as well as microplastic are presented individually in detail. In addition to a brief description of the chemical–physical characteristics and the use of the substance, an overview of main health risks and, in particular, references to further scientific literature are given. In the foreground, however, are extensive presentations of the occurrence of the substances in indoor air and in house dust.
The advancement of the Internet of Things applications (technologies and enabling platforms), consisting of software and hardware (e.g., sensors, actuators, etc.), allows healthcare providers and users to analyze and measure physical environments at home or hospital. The measured physical environment parameters contribute to improving healthcare in real time. Researchers in this domain require existing representative datasets to develop machine-learning techniques to learn physical variables from the surrounding environments. The available environmental datasets are rare and need too much effort to be generated. To our knowledge, it has been noticed that no datasets are available for some countries, including Saudi Arabia. Therefore, this paper presents one of the first environmental data generated in Saudi Arabia’s environment. The advantage of this dataset is to encourage researchers to investigate the effectiveness of machine learning in such an environment. The collected data will also help utilize the machine learning and deep learning algorithms in smart home and health care applications based on the Saudi Arabia environment. Saudi Arabia has a special environment in each session, especially in the northern area where we work, where it is too hot in the summer and cold in the winter. Therefore, environmental data measurements in both sessions are important for the research community, especially those working in smart and healthcare environments. The dataset is generated based on the indoor environment from six sensors (timestamps, light, temperature, humidity, pressure, and altitude sensors). The room data were collected for 31 days in July 2022, acquiring 8910 records. The datasets include six columns of different data types that represent sensor values. During the experiment, the sensors captured the data every 5 min, storing them in a comma-separated value file. The data are already validated and publicly available at PLOMS Press and can be applied for training, testing, and validating machine learning algorithms. This is the first dataset developed by the authors for the research community for such an environment, and other datasets will follow it in different environments and places.
Indoor air pollution is a major threat to human health. Although there are both organic and inorganic sources that contribute to indoor pollution, organic sources play a predominant role. The indoor air is contaminated with a variety of microbes such as bacteria, viruses, and fungi. Among all microbes, fungi cause major health hazards as they find optimum conditions to grow inside closed rooms, buildings, and damp environments. The fungi release volatile fungal metabolites, mycotoxins, and other secondary metabolites that induce allergies and hypersensitivity reactions in human beings. In this chapter, the potential role of fungi in indoor air pollution, the types of volatile compounds and mycotoxins released by fungus, their mechanism of action, implications of these compounds on human health, and their control measures have been discussed in detail.KeywordsVolatile fungal metabolitesMycotoxinsHypersensitivity reactionsSick building syndromeMucous membrane respiratory syndrome
The presence of dampness and visible molds leads to concerns of poor indoor air quality which has been consistently linked with increased exacerbation and development of allergy and respiratory diseases. Due to the limitations of epidemiological surveys, the actual fungal exposure characteristics in residences has not been sufficiently understood. This study aimed to characterize household fungal diversity and its annual temporal and spatial variations. We developed combined cross‐sectional survey, repeated air sampling around a year, and DNA sequencing methods. The questionnaire survey was conducted in 2019, and 4943 valid cases were received from parents; a follow‐up case–control study (11 cases and 12 controls) was designed, and onsite measurements of indoor environments were repeated in typical summer, transient season, and winter; dust from floor and beddings in children's room were collected and ITS based DNA sequencing of totally 68 samples was conducted. Results from 3361 children without changes to their residences since birth verified the significant associations of indoor dampness/mold indicators and prevalence of children‐reported diseases, with increased adjusted odd ratios (aORs) >1 for studied asthma, wheeze, allergic rhinitis, and eczema. The airborne fungal concentrations from air sampling were higher than 1000 CFU/m3 in summer, regardless of indoors and outdoors, indicating an intermediate pollution level. The DNA sequencing for dust showed the Aspergillus was the predominant at genus level and the Aspergillus_penicillioides was the most common at species level; while the fungal community and composition varied significantly in different homes and seasons, according to α and β diversity analyses. The comprehensive research methods contribute to a holistic understanding of indoor fungal exposure, including the concentrations, seasonal variations, community, and diversity, and verifies the relations with children's adverse health outcomes. The study further elucidates the role of microbiome in human health, which helps setting health‐protective thresholds and managing mold treatments in buildings, to promote indoor air quality and human well‐beings.
An air curtain machine is used in the entrances and exits of public places where air conditioners are used. The high-speed centrifugal or axial fan blows out the air, creating an airflow barrier to prevent air convection inside and outside, reducing air conditioning losses, and maintaining the indoor air quality by preventing dust, insects, and harmful gases from entering the room. Observation of the airflow behavior was conducted using CFD simulation, to explore whether it has a blocking effect, and the air curtain principle was applied to the air purification equipment. It is mainly composed of several rows of arrayed hole air outlets to form a multi-composite air wall. The airflow on the two sides, or below, can be blocked by the composite air wall and integrated into the main airflow, so that the air walls will not affect each other, and form a barrier effect to prevent infection. This research includes the measurement of impedance characteristics for three layers of filters made of different materials. These filters are used as the input characteristic parameters in the simulation analysis. Four scenarios are discussed, including the consultation room, hospital ward, quarantine station, and conference room. From the simulation results, it is known that when there are many people, the equipment can be set to high speed to increase the volume of air, forming a wind wall to effectively block airflow from the people in the chairs, reducing the risk of infection. Note that the rotation speed should not be too high. The air outlet equipment is susceptible to turbulent flow, which will make the airflow deviate from the expected direction and increase the possibility of mutual infection between adjacent people. Partitions can be used to block airflow to reduce the risk of infection.
Maden sektörü, taş ocağı işletmeleri, cam ve seramik sektörleri gibi birçok sektörde yoğun olarak karşılaşılan ve çalışan sağlığı üzerinde ciddi meslek hastalıklarına sebep olan silika tozu iç ortam hava kalitesini olumsuz bir şekilde etkilemektedir. Bu çalışmada kapalı ortamlarda yapılan çalışmalarda iç ortam hava kalitesine etki eden faktörlerden birisi olan ve maden sektöründe yoğun olarak görülen kristal yapıdaki silika tozunun çalışma ortamında ve çalışanlar üzerindeki maruziyeti analiz edilmiş ve çalışanların sağlığı üzerindeki etkileri incelenmiştir. Elde edilen veriler incelendiğinde, çalışanlara yapılan kişisel silika tozu maruziyet ölçümleri, yasal mevzuatta 2,4 mg(m3)-1 olarak belirlenen eşik sınır değerine yakın olduğu, çalışma ortamlarında alınan silika tozu maruziyet ölçümlerinin ise yasal mevzuatta belirtilen 2,4 mg(m3)-1’ün altında olduğu gözlemlenmiştir. Analiz sonucunda elde edilen bulgular literatür ışığında tartışılmış ve sonuçlandırılmıştır.
Poor air quality is becoming a critical environmental concern in different countries over the last several years. Most of the air pollutants have serious consequences on human health and wellbeing. In this context, efficient forecasting of air pollutants is currently crucial to predict future events with a view to taking corrective actions and framing effective environmental policies. Although deep learning (DL) as well as statistical forecasting models are investigated in the literature, they have rarely used in air pollutant-specific optimal model building for long-term forecasting. In this paper, our aim is to develop the pollutant-specific optimal forecasting models for the phases spanning from preprocessing to model building by investigating a set of predictive techniques. In this regard, this paper presents a methodology for long-term forecasting of some important air pollutants. More specifically, a total of eight best performing models such as stacked LSTM, LSTM auto-encoder, Bi-LSTM, convLSTM, Holt-Winters, auto-regressive (AR), SARIMA, and Prophet are investigated for developing pollutant-specific optimal forecasting models. The study is carried out based on the real-world data obtained from government-run air quality monitoring units in Kolkata over a period of 4 years. The models such as Holt-Winters, Bi-LSTM, and ConvLSTM achieve high forecasting accuracy with respect to MAE and RMSE values for majority of the pollutants.
School‐age children are particularly susceptible to exposure to air pollutants. To quantify factors affecting children’s exposure at school, indoor and outdoor microenvironmental air pollutant concentrations were measured at 32 selected primary and secondary schools in Hong Kong. Real‐time PM10, PM2.5, NO2 and O3 concentrations were measured in 76 classrooms and 23 non‐classrooms. Potential explanatory factors related to building characteristics, ventilation practice, and occupant activities were measured or recorded. Their relationship with indoor measured concentrations were examined using mixed linear regression models. Ten factors were significantly associated with indoor microenvironmental concentrations, together accounting for 74%, 61%, 46% and 38% of variations observed for PM2.5, PM10, O3 and NO2 microenvironmental concentrations respectively. Outdoor concentration is the single largest predictor for indoor concentrations. Infiltrated outdoor air pollution contributes to 90%, 70%, 75% and 50% of PM2.5, PM10, O3 and NO2 microenvironmental concentrations, respectively, in classrooms during school hours. Interventions to reduce indoor microenvironmental concentrations can be prioritized in reducing ambient air pollution and infiltration of outdoor pollution. Infiltration factors derived from linear regression models provide useful information on outdoor infiltration and help address the gap in generalizable parameter values that can be used to predict school microenvironmental concentrations.
This study examined indoor air pollutants and their health effects on allergic rhinitis in 3,194 employees of 226 bus station halls and then constructed a nomogram model to predict allergic rhinitis risk in those employees. Indoor air temperature, relative humidity, PM10, PM2.5, total bacteria, and total fungi were measured, and questionnaires were used to collect basic station information and employee health information. The results revealed that the over‐standard rates of PM10, PM2.5, total bacteria, and total fungi were 18.16%, 31.13%, 2.22%, and 55.89%, respectively. Seasonal variations were found in temperature, relative humidity, and PM2.5. Passenger flow could affect temperature, and total bacteria. Central air conditioning could affect total bacteria. A total of 15.90% of the employees were diagnosed as allergic rhinitis by physicians. Relative humidity, fungi, self‐reported allergic rhinitis symptoms, and exposure to smoking were the influencing factors for allergic rhinitis. These four variables were incorporated to construct a nomogram. The concordance index of the nomogram was 0.775 (95% CI: 0.745–0.806) and 0.749 (95% CI: 0.715–0.783) for the training cohort and test cohort, respectively. The calibration plot revealed that the nomogram model exhibited good discrimination and consistency. This nomogram model may help predict the occurrence of allergic rhinitis.
The wide adoption of combined heat and power (CHP) can not only improve energy efficiency, but also strengthens energy system resiliency. While CHP reduces overall emissions compared to generating the same amount of electricity and heat separately, its on-site nature also means that CHP facilities operate in populated areas, raising concerns over their near-source air quality impact. Evaluation of the near-source impact of distributed CHP is limited by emission data availability, especially in terms of particulate matter (PM). In this paper, we report on stack emission testing results of a community-scale CHP plant with two natural gas turbine units (15 MW each) from measurements conducted in both 2010 and 2015, and assess the near-source air quality impact using an integrated modeling framework using the stack test results, site-specific meteorological data and terrain profiles with buildings. The NOx removal efficiency by selective catalytic reduction (SCR) is estimated to be ∼83% according to the emission testing. The integrated framework employs AERMOD to screen air quality in a 2.7 km × 2.3 km domain from 2011 to 2015 to identify the highest ground-level concentrations (GLCs). Examining the corresponding meteorological conditions, we find that those high GLCs appeared during the stable atmospheric boundary layer with relative high wind speed. Next, the worse-case scenarios identified from the screening process are simulated using the detailed Unsteady Reynolds Averaged Navier-Stokes (URANS) model coupled with a chemistry solver. The results generally show low GLCs of primary PM2.5 for this case study. However, our analysis also suggests greater building downwash impacts with the presence of taller and denser urban structures. Therefore, the near-source impact of natural gas-fired CHP in large metropolitan areas is worthy of further investigation.
Background:
Traffic-related air pollution is emerging as a risk factor for Alzheimer's disease (AD) and impaired brain development. Individual differences in vulnerability to air pollution may involve the allele of Apolipoprotein E (APOE) gene, the primary genetic risk factor for AD.
Objective:
We analyzed whether the association between traffic air pollution and neurodevelopmental outcomes is modified by APOE ε4 status in children.
Methods:
Data on parent-reported behavior problems (total difficulties scores, Strengths and Difficulties Questionnaire), teacher-reported attention-deficit hyperactivity disorder (ADHD) symptom scores, cognitive performance trajectories (computerized tests of inattentiveness and working memory repeated 2-4 times during January 2012-March 2013), and APOE genotypes were obtained for 1,667 children age 7-11 y attending 39 schools in or near Barcelona. Basal ganglia volume (putamen, caudate, and globus pallidum) was measured in 163 of the children by MRI (October 2012-April 2014.) Average annual outdoor polycyclic aromatic hydrocarbons (PAHs), elemental carbon (EC), and nitrogen dioxide (NO2) concentrations were estimated based on measurements at each school (two 1-wk campaigns conducted 6 months apart in 2012).
Results:
APOE ε4 allele carriers had significantly higher behavior problem scores than noncarriers, and adverse associations with PAHs and NO2 were stronger or limited to carriers for behavior problem scores (P-interaction 0.03 and 0.04), caudate volume (P-interaction 0.04 and 0.03), and inattentiveness trajectories (P-interaction 0.15 and 0.08, respectively). Patterns of associations with the same outcomes were similar for EC.
Conclusion:
PAHs, EC, and were associated with higher behavior problem scores, smaller reductions in inattentiveness over time, and smaller caudate volume in APOE ε4 allele carriers in our study population, and corresponding associations were weak or absent among noncarriers. These findings support a potential role of APOE in biological mechanisms that may contribute to associations between air pollution and neurobehavioral outcomes in children. https://doi.org/10.1289/EHP2246.
Objective
The aim of this study was to perform an exposure assessment of PM2.5 (particulate matter less than 2.5μm in aerodynamic diameter) among children and to explore the potential sources of exposure from both indoor and outdoor environments.
Methods
In terms of real-time exposure measurements of PM2.5, we collected data from 57 children aged 8–12 years (9.64 ± 0.93 years) in two schools in Shanghai, China. Simultaneously, questionnaire surveys and time-activity diaries were used to estimate the environment at home and daily time-activity patterns in order to estimate the exposure dose of PM2.5 in these children. Principle component regression analysis was used to explore the influence of potential sources of PM2.5 exposure.
Results
All the median personal exposure and microenvironment PM2.5 concentrations greatly exceeded the daily 24-h PM2.5 Ambient Air Quality Standards of China, the USA, and the World Health Organization (WHO). The median Etotal (the sum of the PM2.5 exposure levels in different microenvironment and fractional time) of all students was 3014.13 (μg.h)/m³. The concentration of time-weighted average (TWA) exposure of all students was 137.01 μg/m³. The median TWA exposure level during the on-campus period (135.81 μg/m³) was significantly higher than the off-campus period (115.50 μg/m³, P = 0.013 < 0.05). Besides ambient air pollution and meteorological conditions, storey height of the classroom and mode of transportation to school were significantly correlated with children’s daily PM2.5 exposure.
Conclusions
Children in the two selected schools were exposed to high concentrations of PM2.5 in winter of 2013 in Shanghai. Their personal PM2.5 exposure was mainly associated with ambient air conditions, storey height of the classroom, and children’s transportation mode to school.
Merida is the largest urban center in the Mexican State of Yucatan. Here domestic sewage is deposited in poorly built septic tanks and is not adequately treated. Because of contamination from such waste, water from the top 20 m of the aquifer is unsuitable for human consumption. Given this situation and because children are highly vulnerable to environmental pollution, including exposure to toxic trace elements, this study focused on evaluating the exposure of children to arsenic (As), chromium (Cr), and mercury (Hg) in water. It also evaluated the relationship between the levels of these elements in water and their concentrations in urine and blood. Among the 33 children monitored in the study, arsenic surpassed WHO limits for blood in 37% of the cases, which could result from the ingestion of poultry contaminated with organoarsenic compounds. In the case of WHO limits for Mercury, 65% of the water samples analyzed, 28% of urine samples, and 12% of blood samples exceeded them. Mercury exposure was correlated with biological sex, some lifestyle factors, and the zone in Merida in which children live. These data suggest that the levels of some toxic metals in children may be affected by water source, socioeconomic factors, and individual behavior.
Background:
Childhood exposure to microbiological agents may influence the development of allergic and respiratory diseases. Apart from home, children spend most of their time at school, which represents an environment of significant exposure to indoor air microbes. Therefore, we aimed to assess how the prevalence of allergic sensitization and asthma in schoolchildren is affected by microbiological exposure within classrooms.
Methods:
Spirometry with bronchodilation, exhaled nitric oxide measurements and skin-prick tests data were retrieved from 858 children aged 8 to 10 years old attending 71 classrooms in 20 primary schools. Air samples were collected in all classrooms using a single-stage microbiological air impactor through agar plates. Gram-negative endotoxins were collected using flow control pumps and analysed by limulus amebocyte lysate assay. Diversity scores were established as the number of different fungal species found in each classroom.
Results:
Classrooms with increased diversity scores showed a significantly lower prevalence of children with atopic sensitization, but not asthma. The risk of sensitization increased with increasing endotoxin exposure in classrooms. Similarly, significantly higher concentrations of Penicillium spp were found in classrooms with a higher number of children with atopic sensitization.
Conclusions:
Although no causal relationships could be established, exposure to higher fungal diversity was protective against allergic sensitization but this was not seen for asthma. In contrast, higher exposure to gram-negative endotoxins and Penicillium spp in primary school's classrooms was associated with increasing odds of allergic sensitization in children. This article is protected by copyright. All rights reserved.
Children are at increased vulnerability to many environmental contaminants compared to adults due to their unique behavior patterns, increased contaminant intake per body weight, and developing biological systems. Depending upon their age, young children may crawl on the floor and may practice increased hand to mouth activity that may increase their dose-intake of specific contaminants that accumulate in dust and other matrices. Children are also smaller in size than adults, resulting in a greater body burden for a given contaminant dose. Because children undergo rapid transitions through particular developmental stages they are also especially vulnerable during certain growth-related time windows. A Special Issue was organized focused on the latest findings in the field of children’s environmental exposure for these reasons. This editorial introduces articles in this Special Issue and emphasizes their main findings in advancing the field. From the many articles submitted to this Special Issue from around the world, 23 were accepted and published. They focus on a variety of research areas such as children’s activity patterns, improved risk assessment methods to estimate exposures, and exposures in various contexts and to various contaminants. The future health of a nation relies on protecting the children from adverse exposures and understanding the etiology of childhood diseases. The field of children’s environmental exposures must consider improved and comprehensive research methods aimed at introducing mitigation strategies locally, nationally, and globally. We are happy to introduce a Special Issue focused on children’s environmental exposure and children’s health and hope that it contributes towards improved health of children.
Background:
A few studies have reported associations between traffic-related air pollution exposure at schools and cognitive development. The role of PM components or sources other than traffic on cognitive development has been little explored.
Objectives:
We aimed to explore the role of PM sources in school air on cognitive development.
Methods:
A cohort of 2618 schoolchildren (average age 8.5 years) belonging to 39 schools in Barcelona (Spain) was followed up for a year. Children completed computerized tests assessing working memory, superior working memory and inattentiveness during four visits. Particulate matter < 2.5 µm (PM2.5) was measured during two one-week campaigns in each school outdoors and in the classroom. Source apportionment resulted in nine sources: mineral, organic/textile/chalk, traffic, secondary sulphate & organics, secondary nitrate, road dust, metallurgy, sea spray, and heavy oil combustion. Differences in cognitive growth trajectories were assessed with mixed models with age-by-source interaction terms.
Results:
An interquartile change increase in indoor traffic-related PM2.5 was associated with reductions in cognitive growth equivalent to 22% (95% confidence interval (CI): 2%, 42%) of the annual change in working memory, 30% (95% CI: 6%, 54%) of the annual change in superior working memory, and 11% (95% CI: 0%, 22%) of the annual change in the inattentiveness scale. None of the other PM2.5 sources was associated with adverse effects on cognitive development.
Conclusions:
Traffic was the only source of fine particles associated with a reduction in cognitive development. Reducing air pollution from traffic at primary schools may result in beneficial effects on cognition.
Unlabelled:
A number of studies have estimated population exposure to PM2.5 by examining modeled or measured outdoor PM2.5 levels. However, few have taken into account the mediating effects of building characteristics on the ingress of PM2.5 from outdoor sources and its impact on population exposure in the indoor domestic environment. This study describes how building simulation can be used to determine the indoor concentration of outdoor-sourced pollution for different housing typologies and how the results can be mapped using building stock models and Geographical Information Systems software to demonstrate the modifying effect of dwellings on occupant exposure to PM2.5 across London. Building archetypes broadly representative of those in the Greater London Authority were simulated for pollution infiltration using EnergyPlus. In addition, the influence of occupant behavior on indoor levels of PM2.5 from outdoor sources was examined using a temperature-dependent window-opening scenario. Results demonstrate a range of I/O ratios of PM2.5 , with detached and semi-detached dwellings most vulnerable to high levels of infiltration. When the results are mapped, central London shows lower I/O ratios of PM2.5 compared with outer London, an apparent inversion of exposure most likely caused by the prevalence of flats rather than detached or semi-detached properties.
Practical implications:
Population exposure to air pollution is typically evaluated using the outdoor concentration of pollutants and does not account for the fact that people in London spend over 80% of their time indoors. In this article, building simulation is used to model the infiltration of outdoor PM2.5 into the domestic indoor environment for dwellings in a London building stock model, and the results mapped. The results show the variation in relative vulnerability of dwellings to pollution infiltration, as well as an estimated absolute indoor concentration across the Greater London Authority (GLA) scaled by local outdoor levels. The practical application of this work is a better understanding of the modifying effect of the building geometry and envelope design on pollution exposure, and how the London building stock may alter exposure. The results will be used to inform population exposure to PM2.5 in future environmental epidemiological studies.
Indoor size-fractioned particulate matter (PM) was measured in seven schools in Milan, to characterize their concentration levels in classrooms, compare the measured concentrations with the recommended guideline values, and provide a preliminary assessment of the efficacy of the intervention measures, based on the guidelines developed by the Italian Ministry of Healthand applied to mitigate exposure to undesirable air pollutants. Indoor sampling was performed from Monday morning to Friday afternoon in three classrooms of each school and was repeated in winter 2011-2012 and 2012-2013. Simultaneously, PM2.5 samples were also collected outdoors. Two different photometers were used to collect the PM continuous data, which were corrected a posteriori using simultaneous gravimetric PM2.5 measurements. Furthermore, the concentrations of carbon dioxide (CO2) were monitored and used to determine the Air Exchange Rates in the classrooms. The results revealed poor IAQ in the school environment. In several cases, the PM2.5 and PM10 24 h concentrations exceeded the 24 h guideline values established by the World Health Organization (WHO). In addition, the indoor CO2 levels often surpassed the CO2 ASHRAE Standard. Our findings confirmed that important indoor sources (human movements, personal clouds, cleaning activities) emitted coarse particles, markedly increasing the measured PM during school hours. In general, the mean PM2.5 indoor concentrations were lower than the average outdoor PM2.5 levels, with I/O ratios generally <1. Fine PM was less affected by indoor sources, exerting a major impact on the PM1-2.5 fraction. Over half of the indoor fine particles were estimated to originate from outdoors. To a first approximation, the intervention proposed to reduce indoor particle levels did not seem to significantly influence the indoor fine PM concentrations. Conversely, the frequent opening of doors and windows appeared to significantly contribute to the reduction of the average indoor CO2 levels.
The purpose of this study was: (i) to characterize the school indoor environment; (ii) to evaluate self-reported prevalence of disease symptoms among Portuguese teachers; and (iii) to evaluate, as far as we know for the first time in Portugal, the impact of the indoor air quality of schools on the prevalence of disease symptoms among teachers. The study was performed in the city of Oporto, starting in 2004; it included the analysis of questionnaires fulfilled by schoolteachers (n = 177), walkthrough surveys of schools grounds, buildings, and individual classrooms (n = 76), as well as indoor air monitoring. Respirable particle increase was related to chalk use and CO2 concentrations widely exceeded reference values. Schools located near traffic lines presented higher benzene and toluene concentrations. The guideline for total viable microorganism concentration was exceeded in 35.6% of classrooms. Significant increases in disease symptoms among teachers could be related to poor indoor air quality, which was mainly due to inefficient ventilation and influence of traffic emissions. Statistically significant correlations were found between central nervous system injuries and the levels of CO2 and total volatile organic compounds, and between upper respiratory problems and mucosal irritation and the levels of TVOC and respirable particles.
Studies of the impact of long-term exposure to outdoor air pollution on the prevalence of respiratory symptoms and lung function in children have yielded mixed results, partly related to differences in study design, exposure assessment, confounder selection and data analysis. We assembled respiratory health and exposure data for >45,000 children from comparable cross-sectional studies in 12 countries. 11 respiratory symptoms were selected, for which comparable questions were asked. Spirometry was performed in about half of the children. Exposure to air pollution was mainly characterised by annual average concentrations of particulate matter with a 50% cut-off aerodynamic diameter of 10 μm (PM(10)) measured at fixed sites within the study areas. Positive associations were found between the average PM(10) concentration and the prevalence of phlegm (OR per 10 μg · m(-3) 1.15, 95% CI 1.02-1.30), hay fever (OR 1.20, 95% CI 0.99-1.46), bronchitis (OR 1.08, 95% CI 0.98-1.19), morning cough (OR 1.15, 95% CI 1.02-1.29) and nocturnal cough (OR 1.13, 95% CI 0.98-1.29). There were no associations with diagnosed asthma or asthma symptoms. PM(10) was not associated with lung function across all studies combined. Our study adds to the evidence that long-term exposure to outdoor air pollution, characterised by the concentration of PM(10), is associated with increased respiratory symptoms.
The goal of this study was to assess the reliability of measurements of the physical characteristics of spiculated masses on mammography. The images used in this study were obtained from the Digital Database for Screening Mammography. Two experienced radiologists measured the properties of 21 images of spiculated masses. The length and width of all spicules and the major axis of the mass were measured. In addition, the observers counted the total number of spicules. Interobserver and intraobserver variability were evaluated using a hypothesis test for equivalence, the intraclass correlation coefficient (ICC) and Bland-Altman statistics. For an equivalence level of 30% of the mean of the senior radiologist's measurement, equivalence was achieved for the measurements of average spicule length (p<0.01), average spicule width (p = 0.03), the length of the major axis (p<0.01) and for the count of the number of spicules (p<0.01). Similarly, with the ICC analysis technique "excellent" inter-rater agreement was observed for the measurements of average spicule length (ICC = 0.770), the length of the major axis (ICC = 0.801) and for the count of the number of spicules (ICC = 0.780). "Fair to good" agreement was observed for the average spicule width (ICC = 0.561). Equivalence was also demonstrated for intraobserver measurements. Physical properties of spiculated masses can be measured reliably on mammography. The interobserver and intraobserver variability for this task is comparable with that reported for other measurements made on medical images.
Background
Significant efforts have been directed toward addressing the adverse health effects of particulate matter, while few data exist to evaluate indoor exposure nationwide in China.
Objectives
This study aimed to investigate dwellings particulate matter levels in the twelve cities in China and provide large data support for policymakers to accelerate the legislative process.
Methods
The current study was based on the CIEHS 2018 study and conducted in 12 cities of China. A total of 2128 air samples were collected from 610 residential households during the summer and winter. Both PM10 and PM2.5 were detected with a light-scattering dust meter in both the living room and bedroom. The Wilcoxon rank-sum test was performed to evaluate the correlations between PM2.5 and PM10 concentrations and both sampling season and site. Ratios of the living room to bedroom were calculated to evaluate the particulate matter variation between rooms. Hierarchical clustering was used to probe the question of whether the concentration varies between cities throughout China.
Results
The geometric means of the PM2.5 in living rooms and bedrooms were 39.80 and 36.55 μg/m³ in the summer, and 70.97 and 67.99 μg/m³ in the winter, respectively. In the summer, approximately 70 % of indoor dwelling PM2.5 exceeded the limit of 25 μg/m³, and for PM10 approximately 60 % of dwellings demonstrated levels higher than 50 μg/m³; the corresponding values were over 90 % and 80 % in winter, respectively. In Shijiazhuang, Lanzhou, Luoyang and Qingdao, the geometric means of the PM2.5 concentrations were observed to be 1.5 to 4.3 times higher during winter than during summer; similar concentrations in summer and winter were observed in Harbin, Wuxi, and Shenzhen, while the PM2.5 concentrations in Panjin were approximately 1.5 times higher in summer than in winter. There was no significant difference in particulate matter concentrations between the living rooms and bedrooms. Scatter plots showed that cities with low GDP and a small population had higher concentrations, while Shenzhen, which has a higher GDP and a large permanent population, had a relatively low concentration of particulate matter.
Conclusions
Our results suggest that indoor air pollution is a severe problem in China. It is necessary to continue monitoring indoor air quality to observe the changing trend under the tremendous effort of the Chinese government.
Sick building syndrome (SBS) is a collection of nonspecific syndromes linked with the built environment. The occurrence of SBS is associated with humidity, ventilation, moulds and microbial compounds exposure. However, no study has reported the association between indoor microbiome and SBS. In this study, 308 students were surveyed for SBS symptoms from 21 classrooms of 7 junior high schools from Johor Bahru, Malaysia, and vacuum dust from floor, desks and chairs was collected. High throughput amplicon sequencing (16S rRNA gene and ITS region) and quantitative PCR were conducted to characterize the absolute concentration of bacteria and fungi taxa. In total, 326 bacterial and 255 fungal genera were detected in dust with large compositional variation among classrooms. Also, half of these samples showed low compositional similarity to microbiome data deposited in the public database. The number of observed OTUs in Gammaproteobacteria was positively associated with SBS (p = 0.004). Eight microbial genera were associated with SBS (p < 0.01). Bacterial genera, Rhodomicrobium, Scytonema and Microcoleus, were protectively (negatively) associated with ocular and throat symptoms and tiredness, and Izhakiella and an unclassified genus from Euzebyaceae were positively associated with the throat and ocular symptoms. Three fungal genera, Polychaeton, Gympopus and an unclassified genus from Microbotryaceae, were mainly positively associated with tiredness. The associations differed with our previous study in microbial compounds (endotoxin and ergosterol) and SBS in the same population, in which nasal and dermal symptoms were affected. A higher indoor relative humidity and visible dampness or mould in classrooms were associated with a higher concentration of potential risk bacteria and a lower concentration of potential protective bacteria (p < 0.01). This is the first study to characterize the SBS-associated microorganisms in the indoor environment, revealing complex interactions between microbiome, SBS symptoms and environmental characteristics.
The air quality in classrooms is a critical factor that affects students’ daily exposure. Although air filtration units (AFUs) were often used to reduce exposure to air pollution in China, the effectiveness of installing AFUs in Chinese classrooms have not been quantitatively studied. Hence, we carried out concurrent air quality experiments in two identical classrooms where one room was equipped with commercial AFUs and the other one relied on the natural introduction of outside air. Measurements were taken during regular school days in the winter at a primary school in Hangzhou, China. Three ventilation modes, i.e., fresh air, mixed air and recirculation mode were evaluated, respectively. We found that classrooms equipped with AFU showed significant PM2.5 reductions, but this was accompanied by CO2 build-ups. In classroom with AFUs on internal recirculation, nearly 70% of the PM2.5 concentration at the beginning of the class was reduced by the end of a 40-min class. However, the CO2 concentration was observed to reach levels that were six times greater than that of the ambient due to inadequate air change rate (<1 h⁻¹). To mitigate the issue of excessive in-classroom CO2 concentration when using AFUs, filtered outside air must be brought in during their operation. In comparison with the internal recirculation mode, we demonstrated that the fresh air mode that draws the supply air from outdoor can considerably lower CO2 build-ups in the classroom with a moderate increase in PM2.5 concentration of 15 ± 10 μg/m³. The findings from this study helps policy makers especially in developing countries with serious air pollution issues to determine whether or not to install AFU in primary schools and what ventilation mode is effective in reducing negative health effects.
Recent years, people pay great attention to fine particle matter (PM2.5) in indoor environment due to its negative impacts on health. Household cooking and severe air pollutant aggravate indoor PM2.5 level, especially during heating season in severe cold region of China. To find the variation of actual household PM2.5 influenced by both cooking activities and penetration from outdoor environment, a field measurement of PM2.5 concentrations in living room of residential buildings was conducted in Harbin, China. Firstly, six households in urban residence were selected to monitor the indoor PM2.5 mass concentration sequentially. Simultaneously, outdoor PM2.5 concentrations, temperature and indoor occupants' behavior were collected. Secondly, indoor to outdoor (I/O) ratios of PM2.5 in each household during monitoring campaigns were calculated. Influence of cooking activities and outdoor penetration on indoor PM2.5 concentrations in living room were also analyzed. Thirdly, some discussions were done for explanation of variation of PM2.5 in urban residential buildings. Results showed that the average PM2.5 mass concentrations varied from 11.7 to 48.6 μg/m³ indoor, while average I/O ratio value ranged from 0.33 to 1.23. Cooking in kitchen had significant impact on PM2.5 mass concentrations in living room, especially when frying, which could lead to peak value of 456.8 μg/m³ within 10 min from background level. Penetration led to the indoor PM2.5 level approximately 2 h behind with outdoor PM2.5 concentrations in general residences.
Children represent one of the most vulnerable parts of the population regarding the effects of pollutants exposure on health. In this study, hair samples were collected between October 2013 and August 2015 from 142 French children originating from different geographical areas (urban and rural) and analysed with a GC/MS-MS method, allowing for the detection of 55 biomarkers for pesticides and metabolites both persistent and non-persistent from different families, including: organochlorines, organophosphates, pyrethroids, azoles, dinitroanilines, oxadiazines, phenylpyrazoles and carboxamidas; 4 polychlorobiphenyls (PCBs) and 5 polybromodiphenylethers (PBDEs). The number of compounds detected in each sample ranged from 9 up to 37 (21 on average), which clearly highlighted the cumulative exposure of the children. The results also showed a wide range of concentration of the pollutants in hair (often more than 100 times higher in the most exposed child compared to the less exposed), suggesting significant disparities in the exposure level, even in children living in the same area. In addition to the detection of currently used chemicals, the presence of persistent organic pollutants (POPs) in children also suggests that the French population is still exposed to POPs nowadays. PCP, DEP, PNP, 3Me4NP, trans-Cl2CA, 3PBA, fipronil and fipronil sulfone, presented statistically significant higher concentration in the hair of boys compared to girls. PCP, PNP and 3Me4NP presented statistically significant higher concentration in younger children. Finally, this study also suggests that local environmental contamination would not be the main source of exposure, and that individual specificities (habits, diet…) would be the main contributors to the exposure to the pollutants analysed here. The present study strongly supports the relevance of hair for the biomonitoring of exposure and provides the first values of organic pollutant concentration in the hair of French children.
Indoor school gyms are environments characterized by high concentrations of different airborne particulate and gaseous pollutants. In particular, like other naturally-ventilated school environments, in addition to indoor pollutants children can be exposed to sub-micron particles and gaseous pollutants emitted by outdoor sources and penetrating the building envelope; moreover, high concentrations of super-micron particles can be reached due to the resuspension phenomena related to the physical activity performed therein. The present paper aims to evaluate the effect of different ventilation methods (natural ventilation, manual airing) and the use of air purifiers in reducing the indoor concentrations of different airborne particles and gaseous pollutants in school gyms. To this end, an experimental campaign was performed in two naturally-ventilated school gyms in Barcelona (Spain) of different volumes and different distance to major urban roads. Indoor and outdoor measurements of particle number, black carbon and PM1-10 concentrations were performed as well as indoor measurements of CO2 and NO2 concentrations. The study revealed that the use of air purifiers with windows kept closed (natural ventilation) can lead to a significant reduction in terms of indoor-to-outdoor concentration ratios. In the smaller gym (air changes per hour of the purifiers, ACH, equal to 9.2 h-1) the I/O ratios were reduced by 93% and 95% in terms of particle number and PM1-10, respectively; whereas in the larger school gym (ACH = 1.7 h-1) the corresponding reductions were 70% and 84%. For manual airing scenarios, the effect of the air purifiers on outdoor-generated sub-micron particles is reduced; in particular, for low ACH values (i.e. ACH = 1.7 h-1), the reduction is quite negligible (6%).
Emerging evidence demonstrates that chronic exposure to air pollution may negatively impact children's cognitive processing and memory. Little is currently known about how air pollution impacts individual children's academic performance through time. Academic performance is practically important, given its linkage to children's future life course trajectories. Individual-level, longitudinal data from 16,000 US primary school students are combined with a tract-level hazardous air pollutant (HAP) measure to assess how kindergarten exposures are associated with competencies in reading, math and science through third grade. We employed linear mixed models with repeated measures within children (e.g., five math tests across four years), clustering within census tracts, and random effects specified at the child- and census tract-levels. Controlling for a comprehensive list of time variant and time invariant covariates, we found statistically significant associations between higher levels of HAPs and lower reading (b = −0.02; p < 0.05), math (b = −0.02; p < 0.001), and science (b = −0.05; p < 0.001) scores. These negative effects of pollution on academic competency in the early primary school years add to the weight of evidence that air pollution harms children's academic potential.
Differentiation of the exposure to PM2.5 (particulate matter less than 2.5 μm in aerodynamic diameter), NO2 and O3 i.e. pollutants of outdoor origin, due to the occupation of office and school microenvironments, was investigated through the quantification of the respective Indoor to Outdoor (I/O) ratios, in simple statistical terms. For that cause, indoor and outdoor observation data were retrieved from the HEALS EDMS database, and more specifically the data from the OFFICAIR and the SINPHONIE EU projects. The I/O ratios were produced and were statistically analyzed in order to be able to study the influence of the indoor environment against the pollutants coming from outdoors. The present statistical approach highlighted also the differences of I/O ratios between the two studied microenvironments for each pollutant. For exposure estimation to the above-mentioned pollutants, the probability and cumulative distribution function (pdf/cdf) empirical approximations led to the conclusion that for offices the I/O ratios of PM2.5 follow a normal distribution, while NO2 and O3 a gamma distribution. Respectively, for schools the I/O ratios of all pollutants follow a lognormal distribution.
Indoor air pollution is associated with numerous adverse health outcomes. Air purifiers are widely used to reduce indoor air pollutants. Ionization air purifiers are becoming increasingly popular for their low power consumption and noise, yet its health effects remain unclear. This randomized, double-blind crossover study is conducted to explore the cardiorespiratory effects of ionization air purification among 44 children in Beijing. Real or sham purification was performed in classrooms for 5 weekdays. Size-fractionated particulate matter (PM), black carbon (BC), ozone (O3), and negative air ions (NAI) were monitored, and cardiorespiratory functions were measured. Mixed-effect models were used to establish associations between exposures and health parameters. Real purification significantly decreased PM and BC, e.g. PM0.5, PM2.5, PM10 and BC were decreased by 48%, 44%, 34% and 50%, respectively. O3 levels were unchanged, while NAI was increased from 12 cm-3 to 12,997 cm-3. Real purification was associated with a 4.4% increase in forced exhaled volume in 1 s (FEV1) and a 14.7% decrease in fractional exhaled nitrogen oxide (FeNO). However, heart rate variability (HRV) was altered negatively. Interaction effects of NAI and PM were observed only on HRV, and alterations in HRV were greater with high NAI. Ionization air purifier could bring substantial respiratory benefits, however, the potential negative effects on HRV need further investigation.
Few prospective studies exist on indoor and outdoor air pollution in relation to adolescent rhinitis. We studied associations between onset and remission of rhinitis among junior high school students in relation to the home and school environment. A two‐year questionnaire cohort study was performed among 1325 students (11‐15 y) in eight schools in Taiyuan, Northern China. Climate and air pollution were measured by direct reading instruments and passive samplers inside and outside the schools at baseline. Associations were calculated by multilevel logistic regression. Two‐year onset of rhinitis and weekly rhinitis were 26.7% and 13.1%, respectively. RH (p<0.001), CO2 (p<0.01) and PM10 (p<0.01) in the classrooms, PM10 (p<0.01) and NO2 (p<0.05) outside the schools, and redecoration (OR=2.25) and dampness/indoor mould at home (OR=2.04) were associated with onset of weekly rhinitis. RH (p<0.05) and CO2 (p<0.05) in the classroom and dampness/indoor mould (OR=0.67) and environmental tobacco smoke (ETS) at home (OR=0.63) reduced remission of rhinitis. In conclusion, dampness/mould and chemical emissions from new materials at home can increase onset of rhinitis and ETS and dampness/mould can reduce the remission. PM10, RH, CO2 and NO2 at school can increase the onset and RH and CO2 can reduce the remission of rhinitis.
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The energy retrofit of existing buildings is a key strategy to reduce the energy costs of the building sector. Amongst the retrofit solutions, the adoption of mechanical ventilation systems represents a necessary approach for buildings with high crowding index, such as schools. The air quality in schools is a main issue since children spend a significant fraction of the year in such microenvironments. To date, the scientific literature has carried out several studies concerning the air quality in naturally ventilated schools worldwide, nonetheless most of the studies performed a general evaluation of the air quality just using the CO 2 as a comprehensive indicator. This is an oversimplified approach since the indoor air quality is affected by several pollutants, including airborne particles, whose behavior cannot be predicted by the CO 2 one. The aim of the research is the evaluation of the effect of the ventilation retrofit in a classroom on different indoor air quality parameters and energy consumption. To this end a mechanical ventilation system with a heat recovery unit was installed in a test-classroom and tests with CO 2 -based demand controlled ventilation were performed. CO 2 levels and indoor-to-outdoor particle concentrations were measured and compared to the pre-retrofit ventilation conditions (i.e. manual airing procedures). Results showed that mechanical ventilation systems have simultaneous positive effects on the different pollutants investigated as well as on ventilation heat losses: indeed, lower indoor-to-outdoor concentration ratios, with respect to the airing approach, were detected simultaneously for CO 2 , sub-micron particles and PM 10 .
Background:
Home fungus exposures may be associated with development or worsening of asthma. Little is known about the effects of school/classroom fungus exposures on asthma morbidity in students.
Objective:
To evaluate the association of school-based fungus exposures on asthma symptoms in both fungus-sensitized and nonsensitized students with asthma.
Methods:
In this prospective study, 280 children with asthma from 37 inner-city schools were phenotypically characterized at baseline and followed-up for 1 year. Fungal spores were collected by using a Burkard air sampler twice during the school year. Clinical outcomes were evaluated throughout the school year and linked to classroom-specific airborne spore sampling. The primary outcome was days with asthma symptoms per 2-week period.
Results:
Fungal spores were present in all classroom samples. The geometric mean of the total fungi was 316.9 spores/m3 and ranged from 15.0 to 59,345.7 spores/m3. There was variability in total fungus quantity between schools and classrooms within the same school. Mitospores were the most commonly detected fungal grouping. Investigation of the individual mitospores revealed that exposure to Alternaria was significantly associated with asthma symptom days in students sensitized to Alternaria (OR = 3.61, CI = 1.34-9.76, P = .01), but not in children not sensitized to Alternaria (OR = 1.04, CI = 0.72-1.49, P = .85). Students sensitized to Alternaria and exposed to high levels (≥75th percentile exposure) had 3.2 more symptom days per 2-week period as compared with students sensitized but exposed to lower levels.
Conclusion:
Children with asthma who are sensitized to Alternaria and exposed to this fungus in their classroom may have significantly more days with asthma symptoms than those who were sensitized and not exposed.
Clinical trial registration:
Clinicaltrials.govNCT01756391.
This study aimed at surveying lower secondary schools in southern Italy, in a highly polluted area. A community close to an industrial area and three villages in rural areas were investigated. Indoor temperature, relative humidity (RH), gaseous pollutants (CO2 and NO2), selected biological pollutants in indoor dust, and the indoor/outdoor mass concentration and elemental composition of PM2.5 were ascertained.
Temperature and RH were within, or close to, the comfort range, while CO2 frequently exceeded the threshold of 1,000 ppm, indicating inadequate air exchange rate. In all the classrooms, median NO2 levels were above the WHO threshold value. Dermatophagoides p. allergen concentration was below the sensitizing threshold, while high endotoxin levels were detected in the classrooms, suggesting schools may produce significant risks for endotoxin exposure.
Concentration and solubility of PM2.5 elements were used to identify the sources of indoor particles. Indoor concentration of most elements was higher than outdoors. Re‐suspension was responsible for the indoor increase of soil components. For elements from industrial emission (Cd, Co, Ni, Pb, Sb, Tl, V) the indoor concentration depended on penetration from the outside. For these elements, differences in rural vs industrial concentrations were found, suggesting industrial sources may influence indoor air quality nearby schools.
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Biomass combustion significantly contributes to indoor and outdoor air pollution and to the adverse health effects observed in the exposed populations. Besides, the contribution to toxicity of the particles derived from combustion of different biomass sources (pellet, wood, charcoal), as well as their biological mode of action, are still poorly understood. In the present study, we investigate the toxicological properties of PM10 particles emitted indoor from a stove fueled with different biomasses. PM10 was sampled by gravimetric methods and particles were chemically analyzed for Polycyclic Aromatic Hydrocarbons (PAHs) and elemental content. Human lung A549 cells were exposed for 24 h to 1–10 μg/cm² PM and different biological endpoints were evaluated to comparatively estimate the cytotoxic, genotoxic and pro-inflammatory effects of the different PMs. Pellet PM decreased cell viability, inducing necrosis, while charcoal and wood ones mainly induced apoptosis. Oxidative stress-related response and cytochrome P450 enzymes activation were observed after exposure to all the biomasses tested. Furthermore, after pellet exposure, DNA lesions and cell cycle arrest were also observed. The severe genotoxic and pro-necrotic effects observed after pellet exposure were likely the consequence of the high metal content. By administering the chelating agent TPEN, the genotoxic effects were indeed rescued. The higher content in PAHs measured in wood and charcoal PMs was likely the reason of the enhanced expression of metabolizing and oxidative stress-related enzymes, like CYP1B1 and HO-1, and the consequent increase in apoptotic cell death. These data suggest that combustion particles from different biomass sources may impact on lung cells according to different pathways, finally producing different toxicities. This is strictly related to the PM chemical composition, which reflects the quality of the combustion and the fuel in particular. Further studies are needed to clarify the role of particle dimension and the molecular mechanisms behind the harmful effects observed.
School facility conditions, environment, and perceptions of safety and learning have been investigated for their impact on child development. However, it is important to consider how the environment separately influences academic performance and attendance after controlling for school and community factors. Using results from the Maryland School Assessment, we considered outcomes of school-level proficiency in reading and math plus attendance and chronic absences, defined as missing 20 or more days, for grades 3-5 and 6-8 at 158 urban schools. Characteristics of the environment included school facility conditions, density of nearby roads, and an index industrial air pollution. Perceptions of school safety, learning, and institutional environment were acquired from a School Climate Survey. Also considered were neighborhood factors at the community statistical area, including demographics, crime, and poverty based on school location. Poisson regression adjusted for over-dispersion was used to model academic achievement and multiple linear models were used for attendance. Each 10-unit change in facility condition index, denoting worse quality buildings, was associated with a decrease in reading (1.0% (95% CI: 0.1-1.9%) and math scores (0.21% (95% CI: 0.20-0.40), while chronic absences increased by 0.75% (95% CI: 0.30-1.39). Each log increase the EPA's Risk Screening Environmental Indicator (RSEI) value for industrial hazards, resulted in a marginally significant trend of increasing absenteeism (p < 0.06), but no association was observed with academic achievement. All results were robust to school-level measures of racial composition, free and reduced meals eligibility, and community poverty and crime. These findings provide empirical evidence for the importance of the community and school environment, including building conditions and neighborhood toxic substance risk, on academic achievement and attendance.
Endocrine-disrupting chemicals (EDCs) might increase the risk of childhood diseases by disrupting hormone-mediated processes that are critical for growth and development during gestation, infancy and childhood. The fetus, infant and child might have enhanced sensitivity to environmental stressors such as EDCs due to their rapid development and increased exposure to some EDCs as a consequence of development-specific behaviour, anatomy and physiology. In this Review, I discuss epidemiological studies examining the relationship between early-life exposure to bisphenol A (BPA), phthalates, triclosan and perfluoroalkyl substances (PFAS) with childhood neurobehavioural disorders and obesity. The available epidemiological evidence suggest that prenatal exposure to several of these ubiquitous EDCs is associated with adverse neurobehaviour (BPA and phthalates) and excess adiposity or increased risk of obesity and/or overweight (PFAS). Quantifying the effects of EDC mixtures, improving EDC exposure assessment, reducing bias from confounding, identifying periods of heightened vulnerability and elucidating the presence and nature of sexually dimorphic EDC effects would enable stronger inferences to be made from epidemiological studies than currently possible. Ultimately, improved estimates of the causal effects of EDC exposures on child health could help identify susceptible subpopulations and lead to public health interventions to reduce these exposures.
Indoor air quality (IAQ) parameters in 73 primary classrooms in Porto were examined for the purpose of assessing levels of volatile organic compounds (VOCs), aldehydes, particulate matter, ventilation rates and bioaerosols within and between schools, and potential sources. Levels of VOCs, aldehydes, PM2.5 , PM10 , bacteria and fungi, carbon dioxide (CO2 ), carbon monoxide, temperature and relative humidity were measured indoors and outdoors and a walkthrough survey was performed concurrently. Ventilation rates were derived from CO2 and occupancy data. Concentrations of CO2 exceeding 1000 ppm were often encountered, indicating poor ventilation. Most VOCs had low concentrations (median of individual species <5 μg/m(3) ) and were below the respective WHO guidelines. Concentrations of particulate matter and culturable bacteria were frequently higher than guidelines/reference values. The variability of VOCs, aldehydes, bioaerosol concentrations and CO2 levels between schools exceeded the variability within schools. These findings indicate that IAQ problems may persist in classrooms where pollutant sources exist and classrooms are poorly ventilated; source control strategies (related to building location, occupant behaviour, maintenance/cleaning activities) are deemed to be the most reliable for the prevention of adverse health consequences in children in schools. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
Inadequate ventilation of classrooms may lead to increased concentrations of pollutants generated indoors in schools. The FRESH study, on the effects of increased classroom ventilation on indoor air quality, was performed in 18 naturally ventilated classrooms of 17 primary schools in the Netherlands during the heating seasons of 2010-2012. In 12 classrooms, ventilation was increased to targeted CO2 concentrations of 800 or 1200 ppm, using a temporary CO2 controlled mechanical ventilation system. Six classrooms were included as controls. In each classroom, data on endotoxin, ß(1,3)-glucans, particles with diameters of less than 10 μm (PM10 ), and less than 2.5 μm (PM2.5 ) and nitrogen dioxide (NO2 ) were collected during three consecutive weeks. Associations between the intervention and these measured indoor air pollution levels were assessed using mixed models, with random classroom-effects. The intervention lowered endotoxin and ß(1,3)-glucan levels and PM10 concentrations significantly. PM10 for instance, was reduced by 25 μg/m³ (95% confidence interval 13-38 μg/m³) from 54 μg/m³ at maximum ventilation rate. No significant differences were found between the two ventilation settings. Concentrations of PM2.5 and NO2 were not affected by the intervention. Our results provide evidence that increasing classroom ventilation is effective in decreasing the concentrations of some indoor generated pollutants. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
BACKGROUND
We tested the hypothesis that classroom carbon dioxide (CO2) concentration is inversely related to child school attendance and educational attainment.METHODS
Concentrations of CO2 were measured over a 3-5 day period in 60 naturally ventilated classrooms of primary school children in Scotland. Concentrations of CO2 were related to the class average annual attendance and proportions attaining a national standard for reading, writing, and numeracy, adjusted for socioeconomic status and class size.RESULTSThe median (interquartile range, IQR) CO2 concentration averaged over the school day was 1086 ppm (922, 1310). In the model, Time Weighted Average CO2 concentrations were inversely associated with school attendance but not academic attainments. An increase of 100 ppm CO2 was associated with a reduced annual attendance of 0.2% (0.04, 0.4) roughly equivalent to 1 half day of school per annum, assuming schools are open on 190 days per year. Indoor temperature and relative humidity were not related to attendance or academic attainment.CONCLUSIONS
Inadequate classroom ventilation, as evidenced by CO2 concentration exceeding 1000 ppm, is not uncommon and may be associated with reduced school attendance. A relationship between inadequate classroom ventilation and adverse health outcomes in children may be present and this needs to be explored.
Good indoor air quality in schools is important to provide a safe, healthy, productive, and comfortable environment for students, teachers, and other school staff. However, existing studies demonstrated that various air pollutants are found in classrooms, sometimes at elevated concentrations. Data also indicated that poor air quality may impact children's health, in particular respiratory health, attendance, and academic performance. Nevertheless, it should be noted that there are other adverse health effects that are less documented. Few data exist for teachers and other adults that work in schools. Allergic individuals seem to be at a higher risk for adverse respiratory health consequences. Air quality improvement represents an important measure for prevention of adverse health consequences in children and adults in schools.
Fungal exposures are believed to play an important role in the development of asthma and atopy, accounting for increased asthmatic symptoms and severe asthma exacerbation. Indoor fungal species vary both in taxa and concentration in different residences and in different regions.
We explored the fungal species spectrum in 88 homes with at least one asthmatic child in the Middle West region of the United States mostly during late spring and fall season in comparison with 85 homes that did not contain an asthmatic child during flu season.
The average fungal spore counts per cubic metre of air in the bedroom of the enrolled child, the main living spaces and outdoor environments, and the culturable fungal colony-forming units per cubic metre of air samples in the main living space from each home were measured.
The results indicated that Cladosporium, Penicillium, Aspergillus, Basidiospores, Epicoccum and Pithomyces were found in more asthmatic homes than in homes without an asthmatic child or existed in higher concentration in asthmatic homes than in homes without an asthmatic child even after adjusting outdoor spore concentration. The results for culturable fungal species confirmed most of these findings even after adjusting for seasonal factors. Although Alternaria was commonly found in both kinds of homes, there was no significant difference in detection rate or concentration of Alternaria between asthmatic homes and homes without an asthmatic child by either spore counting or culturable airborne detection.
Since many allergens have been identified in these fungal species, identifying and controlling these fungal species in asthmatic homes might be expected to improve asthma care and benefit asthmatic children.
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This study focuses on the relationship between classroom ventilation rates and academic achievement. One hundred elementary schools of two school districts in the southwest United States were included in the study. Ventilation rates were estimated from fifth-grade classrooms (one per school) using CO(2) concentrations measured during occupied school days. In addition, standardized test scores and background data related to students in the classrooms studied were obtained from the districts. Of 100 classrooms, 87 had ventilation rates below recommended guidelines based on ASHRAE Standard 62 as of 2004. There is a linear association between classroom ventilation rates and students' academic achievement within the range of 0.9-7.1 l/s per person. For every unit (1 l/s per person) increase in the ventilation rate within that range, the proportion of students passing standardized test (i.e., scoring satisfactory or above) is expected to increase by 2.9% (95%CI 0.9-4.8%) for math and 2.7% (0.5-4.9%) for reading. The linear relationship observed may level off or change direction with higher ventilation rates, but given the limited number of observations, we were unable to test this hypothesis. A larger sample size is needed for estimating the effect of classroom ventilation rates higher than 7.1 l/s per person on academic achievement.
Practical implications:
The results of this study suggest that increasing the ventilation rates toward recommended guideline ventilation rates in classrooms should translate into improved academic achievement of students. More studies are needed to fully understand the relationships between ventilation rate, other indoor environmental quality parameters, and their effects on students' health and achievement. Achieving the recommended guidelines and pursuing better understanding of the underlying relationships would ultimately support both sustainable and productive school environments for students and personnel.
Abstract
Abstract The indoor air quality of 27 primary schools located in the city centre and suburbs of Antwerp, Belgium, was assessed. The primary aim was to obtain correlations between the various pollutant levels. Indoor:outdoor ratios and the building and classroom characteristics of each school were investigated. This paper presents results on indoor and local outdoor PM2.5 mass concentrations, its elemental composition in terms of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb, Al, Si, S, and Cl, and its black smoke content. In addition, indoor and local outdoor levels of the gases NO2, SO2, O3, and BTEX (benzene, toluene, ethyl benzene, and xylene isomers) were determined. Black smoke, NO2, SO2 and O3, occurred at indoor:outdoor ratios below unity, indicating their significant outdoor sources. No linear correlation was established between indoor and outdoor levels for PM2.5 mass concentrations and BTEX; their indoor:outdoor ratios exceeded unity except for benzene. Classroom PM2.5 occurred with a different elemental composition than local outdoor PM2.5. The re-suspension of dust because of room occupation is probably the main contributor for the I/O ratios higher than 1 reported for elements typically constituting dust particles. Finally, increased benzene concentrations were reported for classrooms located at the lower levels.
Whether local exposure to major roadways adversely affects lung-function growth during the period of rapid lung development that takes place between 10 and 18 years of age is unknown. This study investigated the association between residential exposure to traffic and 8-year lung-function growth.
In this prospective study, 3677 children (mean age 10 years [SD 0.44]) participated from 12 southern California communities that represent a wide range in regional air quality. Children were followed up for 8 years, with yearly lung-function measurements recorded. For each child, we identified several indicators of residential exposure to traffic from large roads. Regression analysis was used to establish whether 8-year growth in lung function was associated with local traffic exposure, and whether local traffic effects were independent of regional air quality.
Children who lived within 500 m of a freeway (motorway) had substantial deficits in 8-year growth of forced expiratory volume in 1 s (FEV(1), -81 mL, p=0.01 [95% CI -143 to -18]) and maximum midexpiratory flow rate (MMEF, -127 mL/s, p=0.03 [-243 to -11), compared with children who lived at least 1500 m from a freeway. Joint models showed that both local exposure to freeways and regional air pollution had detrimental, and independent, effects on lung-function growth. Pronounced deficits in attained lung function at age 18 years were recorded for those living within 500 m of a freeway, with mean percent-predicted 97.0% for FEV1 (p=0.013, relative to >1500 m [95% CI 94.6-99.4]) and 93.4% for MMEF (p=0.006 [95% CI 89.1-97.7]).
Local exposure to traffic on a freeway has adverse effects on children's lung development, which are independent of regional air quality, and which could result in important deficits in attained lung function in later life.