Poor indoor air quality in schools is associated with diminished learning, health risks to students and staff, and economic costs. This dissertation reports findings from the Texas Elementary School Indoor Air Study (TESIAS). The objective of this investigation is to establish a baseline for indoor environmental parameters. The investigation selected 30 elementary schools from 2 school districts. One school district was located along the Texas/Mexico border in a hot-humid climate region. The other school district was located in central Texas in a mixed-humid climate region. Phase I of the study was a questionnaire completed by 1336 teachers and other school staff. Phase II of the study collected both qualitative and quantitative data in 120 classrooms including continuous monitoring of comfort parameters (carbon monoxide, carbon dioxide, temperature, and relative humidity). Phase III collected more in-depth quantitative data, including fungi and bacteria concentrations, in 12 classrooms. This dissertation investigates potential differences in the study data between school districts and between portable and traditional classrooms. The two major findings of this study concern water leakage from roofs and inadequate ventilation. Roof leaks were the highest reported source of water incursion and correlated with health symptoms. Free-standing small footprint classrooms had fewer roof and wall leaks than traditional classrooms. The simple low pitch roof design and sufficient overhangs typically found on the small footprint buildings studied likely result in less reported roof leaks. The measured carbon dioxide concentrations (both average and peak values) were well in excess of the recommended maximums and fewer than 15% of the classrooms met the recommended maximum concentrations. Relatively higher CO2 concentrations and relative humidity in the border school district were attributed to a greater frequency of blocked outdoor air intakes. Further investigation of novel HVAC systems, such as low velocity displacement ventilation, is needed. Ultimately, this study enables the development of best practices for school design for improved indoor air quality. / text

Background: Air pollution is a serious concern all over the world, and there have been numerous studies showing its adverse effects on health outcomes including disease-specific hospitalization and mortality. Most of these studies were conducted in Western settings and focused on NO2, SO2, PM10 and black smoke; limited results on PM2.5 in Asia have been published. Objectives: This study attempted to identify association between PM2.5 concentration and daily mortality due to all-natural causes, cardiovascular diseases, and respiratory diseases in Hong Kong, a tropical city in Asia from 2008 to 2011. Methods: The study used a case-crossover study design with time-stratified referent selection strategy. The referents were selected on the same day of the week of the same month and year as the event day. In this way, biases due to autocorrelation, time trend, and seasonal pattern were controlled for by study design. Covariates including temperature, humidity, and gaseous pollutants (NO2, SO2, O3 and CO) were adjusted for by statistical modelling. The statistical method applied was Conditional Logistic Regression. Sensitive analyses using matched by month strategy were also conducted to check the robustness of the main analyses. The health outcome variables included were mortality due to all natural causes, cardiovascular disease, and respiratory disease. Each model was examined for effects of PM2.5 at each lag 0 through lag 5 day and, for the current and lag 1 day moving average (lag 0-1). Effects were measured in Excess Risks (ER) associated with 10 μg/m^3 increase in PM2.5. Results: Significant associations with PM2.5 were observed for mortality from all natural causes and cardiovascular disease at lag 0, lag 1, and lag 0-1; and from respiratory disease only at lag 1. At lag 0-1, PM2.5 was associated with mortality from all natural causes, cardiovascular disease, and respiratory disease with the ER (95% confidence interval) of 0.74% (95% CI: 0.29, 1.19), 1.4% (95% CI: 0.52, 2.27), and 0.67% (95% CI: -0.30, 1.64), respectively. After adjusting for each of the co-pollutants in two-pollutant model, the effect magnitude dropped except that one adjusting for CO. The ERs of mortality in co-pollutant models from all natural causes ranged from 0.23% to 1.72%, from cardiovascular disease ranged from 1.00% to 2.93%, and from respiratory disease ranged from -0.10% to 1.83%. The results were robust in sensitivity analyses. Conclusion: My study provides some information to support formulation of air quality control strategies and policies, and for updating air quality standards. Such information includes the overall and seasonal patterns of air pollutants and mortality in Hong Kong, as well as the excess risks of mortality associated with increase in PM2.5. Studies with individual data stratified for subgroups can be conducted in the future to investigate effect modification of lifestyle factors for the individuals and population. / published_or_final_version / Public Health / Master / Master of Public Health

Low-income communities are potentially more vulnerable to physical, social and environmental hazards than wealthier communities. The lack of services associated with these communities (such as water supply, sanitation facilities and electrification) has increased the exposure of households to health hazards. These households also lack the coping mechanisms and resources to deal with the stress that these hazards impose on them. This study is concerned with the potential health hazards imposed from indoor air pollution. Traditional health risk assessments are used to determine the level of risk to human health from a variety of chemical or biological hazards. What these assessments do not include however, is a measure of the vulnerability of the household. The aim of this study therefore, was to develop a methodology for generating a vulnerability index for the inclusion of factors underlying urban poverty and vulnerability into a risk assessment of indoor air pollution. The approach adopted in this study followed an iterative and inductive pathway. Theories on risk assessment and urban vulnerability were explored in order to understand the manner in which risk to human health is assessed and compounded by vulnerability. Secondary data sources as well as a household survey provided information that aided the selection of a number of vulnerability indicators. These indicators were chosen as measures of vulnerability specifically for low-income households in South African settlements. The findings of the research show that there are a number of factors or issues which underlie vulnerability. The issues are related to demographics, livelihoods, physical exposures, externalities, services and general health. This study used a four-tiered selection approach to sift through the issues of vulnerability and to transform the key issues into a set of vulnerability indicators which make up the vulnerability index. / Thesis (M.Sc.)-University of Natal, Durban, 2003.

Thesis (M.Tech.: Environmental Health)-Durban Institute of Technology, 2005 1 v. : ill. ; 30 cm / South Durban is in the province of Kwazulu-Natal in South Africa and is home to two international petro-chemical refineries, a paper mill, sewage works, an international airport, a chemical tank farm with approximately 970 tanks, a number of landfill sites, an airport, various processing and manufacturing industries which are all in close proximity to residential and recreational areas. This area is known as the South Durban Industrial Basin (SDIB). Serious concerns have arisen about the potential health impacts that could arise from ambient air pollution from these industries. Learners and staff at the Settlers Primary School situated in Merebank, a suburb in the SDIB, perceived themselves to be at risk for air pollutant related health effects owing to the schools’ geographic location. The aims of this study was a) to determine the prevalence of asthma among learners from Grades 3 and 6 and staff at Settlers Primary School and b) To investigate whether outdoor air pollutant concentrations of sulphur dioxide (SO2), oxides of nitrogen (NOx), ozone (O3), total reduced sulphur (TRS), carbon monoxide (CO) and respirable particulate matter less than 10 microns (PM10) were associated with increased signs and symptoms of asthma in the study population.

Thesis (MPH.) -- University of Limpopo, 2016. / Introduction: Annually, hundred thousands of people worldwide die as a result of second hand smoke (SHS) exposure. There is no safe exposure level to SHS yet in Bulawayo, smokers have been observed smoking without restraint thus exposing non-smokers to SHS. The purpose of this study was to establish the prevalence and contributing factors of SHS exposure among adults in Bulawayo, Zimbabwe. Methods: A cross sectional study was conducted and participants were randomly selected from residents who visited the 13 municipal revenue halls. A structured questionnaire was used to collect data from respondents. Descriptive and multivariate logistic regression analyses were performed. Results: Home SHS exposure prevalence was 22% and females were 2.11 times more likely than males to be exposed at home. Prevalence of SHS exposure in public transportation, health facilities, educational and food premises was 40.9%, 26.3%, 42,9% and 36.8% respectively. Conclusion: SHS exposure in Bulawayo was high and there is need to reduce SHS exposure to non-smoking adults. Keywords: Second hand smoke (SHS), Bulawayo, Prevalence, Exposure, Adult

Ambient exposure to fine particulate matter (PM2.5) and ground-level ozone (O3) is identified as a leading risk factor for global disease burden. A major limitation to advancing our understanding of the cause and impacts of air pollution is the lack of observations with the spatial and temporal resolution needed to observe variability in emission, chemistry and population exposure. Satellite remote sensing, which fills a spatial gap in ground-based networks, is playing an increasingly important role in atmospheric chemistry. This thesis exploits satellite remote sensing observations to: (1) estimate human exposure to PM2.5 from remotely sensed aerosol optical properties; (2) identify the chemical regimes of surface O3 formation using satellite observations of O3 precursors. In the first part, we use a forward geophysical approach to derive PM2.5 distributions from satellite AOD at 1 km2 resolution over the northeastern US by applying relationships between PM2.5 and AOD simulated from a regional air quality model (CMAQ). We use multi-platform ground, airborne and radiosonde measurements to quantify multiple sources of uncertainties in the satellite-derived PM2.5. We find that uncertainties in satellite-derived PM2.5 are largely attributed to the varying relationship between PM2.5 and AOD that depends on the aerosol vertical distribution, speciation, aerosol optical properties and ambient relative humidity. To assess the value of remote sensing to improve PM2.5 exposure estimate, we compile multiple PM2.5 products that include information from remote sensing, ground-based observations and models. Evaluating these products using independent observations, we find the inclusion of satellite remote sensing improves the representativeness of surface PM2.5 mostly in the remote areas with sparse monitors. Due to the success of emission control, PM2.5-related mortality burden over NYS decreased by 67% from 8410 (95% confidence interval (CI): 4, 570 – 12, 400) deaths in 2002 to 2750 (95% CI: 700 – 5790) deaths in 2012. We estimate a 28% uncertainty in the state-level PM2.5 mortality burden due to the choice of PM2.5 products, but such uncertainty is much smaller than the uncertainty (130%) associated with the exposure-response function. The second part of the thesis focuses on ground-level O3. O3 production over urban areas is non-linearly dependent on the availability of its precursors: nitrogen oxides (NOx) and volatile organic compounds (VOCs). A major challenge in lowering ground-level O3 in urban areas is to determine the limiting species for O3 production (NOx-limited or VOC-limited). We use satellite observations of NO2 and HCHO to infer the relative abundance of NOx versus VOCs, thus to identify the O3 chemical regime. We first use a global chemical transport model (GEOS-Chem) to evaluate the uncertainties of using satellite-based HCHO/NO2 to infer O3 sensitivity to precursor emissions. Next, we directly connect this space-based indicator, retrieved consistently from three satellite instruments, to spatiotemporal variations in O3 recorded by on-the-ground monitors from 1996 to 2016. The nationwide emission reduction has led the O3 formation over U.S. urban areas to shift from VOC-limited to NOx-limited regime. Urban O3 monitors reveal trends consistent with this regime transition. Nonetheless, it is a major challenge for these retrievals to accurately depict day-to-day variability within urban cores. TROPOspheric Monitoring Instrument (TROPOMI) which launched in 2017, offers an unprecedented view to infer O3 chemistry at fine spatial and temporal scales. As an example, we use TROPOMI HCHO/NO2 to identify short-term changes in O3 sensitivity during the California Camp Fire. We find that the emissions from wildfires lead to NOx-saturated ozone formation near the fire source but NOx -limited conditions downwind. This thesis bridges basic research in atmospheric chemistry, which advances the state-of-science related to O3 and PM2.5 pollution from urban to global scales, and applied research in air quality management and public health, by quantifying the health benefits of emission control, and informs policymakers on which emission reductions to focus so as to maximize the cost-effectiveness of pollution controls. We show how space-based measurements can complement in situ networks and model simulations by providing information on the spatial heterogeneity and temporal evolution of PM2.5 exposure and O3 chemical regimes, which will lay the scientific foundation for interpreting future products retrieved from upcoming geostationary platforms.

High PM2.5-related mortality and morbidity has become a public health concern in China. To date, there have been few studies investigating individual implementation and use of protective behaviors to counter outdoor PM2.5 air pollution levels in China. This study, therefore, aimed to investigate adults’ attitudes toward evidence-based protective behaviors against outdoor PM2.5 air pollution, the results of which might inform health educators and health promotion specialists about what they should emphasize when educating communities about protective behaviors in the PM2.5 air pollution days. Utilizing the purposing sampling method, a WeChat-based survey was conducted among 300 adult participants living in B residential area in Yuhuatai district of Nanjing, which is a representative city of high urbanization level and PM2.5 air pollution in China. The survey included total 16 items assessing participants’ background information, attitudes toward four evidence-based protective behaviors against PM2.5 air pollution, and knowledge regarding possibly effective protective approaches specifically related to Chinese medicine in the PM2.5 air pollution. The results showed that the importance adults in Nanjing attached to wearing N95 respirator when walking outside, putting air filter (HEPA) at home, and avoiding unprotected outdoor sports activities in the PM2.5 air pollution was greater than closing all the doors, windows, and many openings in the PM2.5 air pollution. Regarding comparison of attitudes between pre- and post-controlled COVID-19 periods, the value adults gave to closing all the doors, windows, and many openings in the PM2.5 air pollution was higher during pre-COVID-19 period, whereas the opposite of circumstance took place when referring to other three protective behaviors. Regarding comparison of attitudes between biographic variables, adults aged 18-50 (including 50) attached greater importance to all the four protective behaviors than those aged 50+. In addition, adults having the habit of checking daily AQI ranked the behaviors of avoiding outdoor sports activities and wearing N95 respirator when walking outside in the PM2.5 air pollution in a higher position than those not. Implications for future research and practice are discussed, based on a critique of the present work.

Air pollution is one of the leading environmental problems of the 21st century, and the rise of global urbanization has increasingly exacerbated air pollution’s public health impact. Existing epidemiologic studies have tackled the relationship between air pollution and health from a variety of perspectives, but many areas of research remain lacking, including studies originating from developing countries, the assessment of exposure windows and sensitivity of modeling choices, and a better understanding of the climate change impacts on air pollution and health. In this dissertation, I address all of the issues mentioned above. Chapter 1 formally introduces the topics of this dissertation and summarizes background information on several major air pollutants. It then provides an overview of existing research on air pollution epidemiology and describes key knowledge gaps. In Chapter 2, we conduct a systematic review of the scientific literature for data on fine particulate matter (PM2.5) in China, where historical PM2.5 data are not widely available prior to 2013. Using the 574 PM2.5 measurements we identified from the literature, we detected differences in PM2.5 levels across both geographic and economic regions of China. In Chapter 3, we investigate the associations between short- and intermediate-term exposure of nitrogen dioxide (NO2) and mortality in 42 counties in China from 2013 to 2015, and find evidence of significant associations up to seven days prior to exposure. In Chapter 4, we investigate the association between PM2.5 and hospitalizations in New York State using five separate exposure datasets from 2002 to 2012. We find that despite some fluctuations in effect estimates, the majority of models yielded consistently significantly harmful associations. In Chapter 5, we utilize a global chemistry-climate model to project ozone levels in 2050 under a variety of emissions scenarios and quantify the mortality impact associated with changes in ozone concentrations between 2015 and 2050 according to each scenario. We find that under climate change alone and adherence to current legislation, ozone-related deaths would increase. However, under a best-case scenario of maximum technologically feasible reductions in emissions, over 300,000 premature deaths related to ozone can be avoided. Finally, Chapter 6 summarizes the findings of this dissertation and discusses potential directions in future research. While much work remains to be done, this dissertation work takes an important step forward in closing existing knowledge gaps in the field of air pollution epidemiology. More importantly, we hope that our work sends a strong public health message on the importance of continuing research on air pollution and health.

Climate change is already harming public health through warmer, more erratic weather and many downstream consequences. Research can support climate change adaptation by characterizing climate-related exposures, identifying vulnerable populations, and identifying effective interventions. Furthermore, the main source of greenhouse gas emissions, fossil fuel combustion, also produces air pollutants such as fine particulate matter (PM2.5) that directly harm human health. In this dissertation my colleagues and I have examined the effects of short-term temperature exposure on myocardial infarction and stroke to inform adaption (Chapters 1 to 3) and leveraged multiple exposure models to estimate annual PM2.5 concentrations and quantify uncertainty (Chapter 4). To examine the effects of short-term temperature exposure, we conducted case-crossover analyses using an administrative dataset of hospitalizations in New York State. For PM2.5 prediction and uncertainty characterization, we applied a flexible ensemble approach to leverage seven already-developed PM2.5 models. Overall, we found that warmer hourly temperatures and greater daily temperature variability increased the risk of ischemic events, and lower hourly temperatures increased the risk of hemorrhagic stroke. The ensemble model showed high predictive accuracy, demonstrating the strength of this approach, and we observed greatest uncertainty in the Pacific Northwest and southeast coast. The methods applied in this dissertation can be applied to other exposures and in different settings to further quantify the risks of climate impacts and improve air pollution assessment. Future research should examine the joint impacts of multiple weather factors, strategies to protect people in group housing from extreme weather, measurements and models to reduce uncertainty of air pollution exposures, and propagate exposure uncertainty into health models. However, the need for further research should not delay climate action today.

Some metals and metalloids make significant contributions to the harmful effects of tobacco consumption although understanding the mechanisms involved in toxicity is hampered by the lack of information on their chemical and valence species, both in tobacco and in smoke. This research addresses the speciation of the metals and metalloids most frequently implicated, particularly those elements that exist in nature in multiple valence states, namely arsenic (As) and chromium (Cr), there being considerable differences in toxicity with oxidation state. A strategy was devised to overcome some of the problems that have thwarted earlier attempts at speciation. Firstly tobacco plants were cultivated under controlled conditions in compost burdened with high levels of metals and metalloids resulting in leaf with up to 250 µg g⁻¹ As, although Cr uptake was less successful. Secondly valence speciation even at the exceptionally low concentrations of As and Cr in smoke from unburdened tobacco was achieved with XANES analysis using the exceptionally bright Diamond synchrotron source. This revealed that combustion of tobacco has a marked effect on valence speciation with As(III), the reduced form of As, dominating (and persisting) in condensate of tobacco smoke while ash is dominated by the oxidised form, As(V). Chromium also appears to be present in smoke mainly as reduced Cr(III) species. HPLC-ICPMS analysis of arsenic indicates the dominance of inorganic over organic species (~4:1). Other metals were investigated in less detail. These findings establish that arsenic is present in smoke in its most toxic form and represents a significant risk to health. Conversely smokers appear to be exposed to the less harmful species of chromium. These results support a recent WHO report that includes As but not Cr in a list of four metals and metalloids recommended for regulation in crops and commercial products in the interests of public health.