Environmental factors can have a significant impact on an individual's health and well-being, and a primary characteristic of environments is air quality. Air sensing equipment is available to the public, but it is often expensive,stationary, or unusable for persons without technical expertise. The goal of this project is to develop an inexpensive and portable sensor module for public use. The system is capable of measuring temperature in Celsius and Fahrenheit, heat index, relative humidity, and carbon dioxide concentration. The sensor module, referred to as the "sniffer," consists of a printed circuit board that interconnects a carbon dioxide sensor, a temperature/humidity sensor, an Arduino microcontroller, and a Bluetooth module. The sniffer is small enough to be worn as a pendant or a belt attachment, and it is rugged enough to consistently collect and transmit data to a user's smartphone throughout their workday. The accompanying smartphone app uses Bluetooth and GPS hardware to collect data and affix samples with a time stamp and GPS coordinates. The accumulated sensor data is saved to a file on the user's phone, which is then examined on a standard computer.

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Elevated concentrations of ambient fine particulate matter (PM2.5) and ozone (O3) contribute to adverse health outcomes in exposed populations. Anthropogenic source sectors, including aviation, residential combustion (RC), and electricity generating units (EGUs), lead to increased concentrations of these combustion-related pollutants. Quantification of the influence of emissions from specific source sectors on ambient pollutant concentrations can be very useful in better informing public health policy decision making on air quality improvements. Due to complex emissions dynamics, background concentrations, and meteorology, determining contributions of these sources to related health risks is challenging. To assess local impacts of aviation activity, concentrations of nitrogen oxides (NOx) and the PM2.5 constituent black carbon (BC) were monitored near airports. Moreover, aviation-attributable fractions were derived from monitored concentrations using regression modeling, and values were compared with predicted aviation-attributable concentrations from a near-field dispersion model. Regional impacts of aviation, RC, and EGUs were assessed using the Community Multiscale Air Quality (CMAQ) atmospheric chemistry and transport model with the Direct Decoupled Method (DDM) to determine sensitivity of ambient PM2.5 and O3 concentrations to emissions from individual sources. Health damage functions, quantified as mortality per thousand tons of emitted precursor species, were created by individual airport for 66 of the highest fuel-burning airports in the United States and by state for RC and EGUs. Physically-interpretable regression models were built to predict aviation-related health damage functions. With local aviation, comparisons of regression-predicted and dispersion-predicted BC and NOx concentrations are similar when aggregated, though diurnal patterns show potential weaknesses in near-field dispersion and emissions inventory accuracy. For regional aviation impacts, health damage function values varied by more than an order of magnitude across airports for each precursor-ambient pollutant pair, with seasonal effects present in secondary pollutant formation. Health damage functions were predicted by combinations of upwind and downwind population, meteorology, and atmospheric chemistry regime. State-resolution contributions of RC and EGUs varied both within and between source sectors, based on local characteristics including population density and EGU location. These findings reinforce the importance of quantification of source-specific air quality and health impacts in the design of health-maximizing emissions control policies.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23494号 / 工博第4906号 / 新制||工||1766(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 高野 裕久, 教授 米田 稔, 准教授 上田 佳代 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Air pollution is the world’s greatest environmental health risk factor and reducing exposure remains an ongoing challenge around the world. Among the world’s poor, marginalized, and rural populations, household air pollution from the inefficient burning of biomass fuels like firewood, charcoal, dung, and agricultural residues for daily household energy needs is a leading cause of morbidity and mortality, especially for children under the age of five years. However, household air pollution exposure is a modifiable risk factor and clean-burning cooking fuels like gas and electricity promise substantial health benefits for the 2.8 billion people reliant on biomass fuels. But, clean fuels remain prohibitively expensive or inaccessible for those most reliant on biomass fuels. It is in this context that I examine Ecuador – where substantial cooking gas subsidies have facilitated a nationwide transition to household clean fuel use over four decades – as a long-term case study to understand the potential for widespread clean fuel uptake to reduce air pollution exposure and improve children’s health. Chapter 1 provides background information that contextualizes the work presented in this dissertation. In Chapter 2, I discuss the development of Ecuador’s clean fuel policies. Originally established as a part of broad social support reforms in the 1970s, direct-to-consumer subsidies that lowered the cost of liquefied petroleum gas (LPG) – a popular clean-burning cooking fuel used widely around the world – have driven a transition from 80% of households cooking primarily with firewood in the 1970s to now 90% relying primarily on LPG. However, widespread clean fuel use has come at a cost; each year, the Government of Ecuador spends approximately 1% of the national growth domestic product subsidizing LPG (300-700 million USD). To reduce this financial burden, the government has offered incentives to households to install and use induction electric stoves, which can be powered by the nation’s growing hydroelectric capacity, thereby reducing the cost of LPG subsidies and greenhouse gas emissions. To supplement national data, I administered household energy surveys in a northern province, finding that while all households regularly used LPG, 80% still used firewood for cooking. In these remote regions along the Colombian border, limited access to LPG cylinder refills remains a significant barrier to exclusive LPG use, even after decades of building a robust distribution system. In Chapter 3, I describe results from tailored household surveys – covering energy end uses, costs and access to fuels, and fuel use preferences – administered in 808 households across coastal and Andean Ecuador. Nearly all participants reported using LPG for more than a decade and having frequent, convenient access to cheap LPG cylinder refills. Nonetheless, half of rural households and one-fifth of peri-urban households relied on firewood for cooking and to meet specific household energy needs, like space heating or heating water for bathing. Induction stoves were rare and many induction stove owners reported zero use because the required equipment had never been installed by electricity companies, their stove had broken, or they feared high electricity costs. Here, I show that nationally-representative surveys reporting only “primary cooking fuel” use may underestimate solid fuel use as a secondary option, particularly in rural areas where LPG fuel availability issues play an important role in cooking fuel decision making. These findings additionally indicate that persistent biomass use may curtail the benefits from even the most aggressive clean fuel policies and suggest that additional targeted interventions may be needed to more fully displace biomass. Furthermore, they highlight the need for more nuanced nationally- and subnationally-representative surveys to better understand the extent to which biomass fuels are used secondary to LPG throughout all regions of Ecuador. In Chapter 4, I present results from a sensor monitoring study where we measured personal PM2.5 exposure and stove use for 48-hour monitoring periods among 157 households in peri- urban and rural Ecuador. Firewood-using participants had higher distributions of 48-hour and 10-minute PM2.5 exposure as compared with primary LPG and induction stove users. Accounting for within-subject clustering, contemporaneous firewood stove use was associated with 101 μg/m3 higher 10-min PM2.5 exposure (95% confidence interval: 94–108 μg/m3). Cooking events with clean fuels were not associated with contemporaneous increases in PM2.5 exposure. These findings confirm our expectations that in a region with low ambient air pollution, long-term cooking gas subsidies can lead to relatively low personal air pollution exposures. And yet, persistent secondary firewood use led to higher average and peak exposures, further motivating the displacement of firewood use to reduce health risks from air pollution. I also outline the methodological challenges faced in combining time-resolved sensor data on participant location, stove use monitors, and PM2.5 concentration and offered advice for future studies. In Chapter 5, I assess whether Ecuador’s increased clean cooking fuel use has resulted in improvements in under-5 lower respiratory infection (LRI) mortality. Globally, LRIs are the leading cause of death for children under-5 and household air pollution exposure is a leading risk factor. I employ public use data on cooking fuel use and cause-coded mortalities from 1990 to 2019 to estimate the association between clean cooking fuel use and the rate of under-5 LRI mortalities at the canton (county) level in Ecuador. Using generalized additive mixed models with fixed effects for canton and study period, I observed a significant, non-linear negative association providing evidence that when more than 60% of households in a canton cook primarily with a clean fuel, increased clean fuel use is associated with reductions in under-5 LRI mortality. In total, I estimated that increased clean cooking fuel use is associated with 7,343 under-5 LRI mortalities averted since 1990. In Chapter 6, I conclude by discussing the broader implications of my work. Energy is an important thread connecting climate change, air pollution, and human health, and pathways towards cleaner energy generation will be important drivers of climate change mitigation, reduced environmental exposures, and improved population health. Investments in clean cookstoves have had mixed results over the last 40 years, with many studies revealing only limited uptake of intervention stoves and substantial continued use of polluting traditional fuels, resulting in lower-than-expected exposure reductions and health benefits. Ecuador’s transition has been remarkable in the context of its peer low- and middle-income countries in the rest of Latin America and beyond. The findings presented in this dissertation demonstrate that cooking gas is popular; when it is made cheap and available, gas significantly displaces the use of polluting fuels. Nevertheless, even under ideal cost and access circumstances, my work also reveals that policies and interventions will need to consider specific local needs – like space heating in cold climates – to further encourage a transition toward cleaner indoor air. In the context of efforts to eliminate the use of polluting fuels in the Americas, my work offers hope that ambitious clean cooking fuel policies will improve health.

The focus of this master’s thesis is the issue of fine dust particles suspended in the air and their measurement. The thesis explains the basic characteristics of fine particles and the rules, which they follow. The section then examines the health risks of inhaled particles. Next is explained the influence of particles in the air on the environment, the historical development of the air pollution in the Czech Republic and the most important pollutants. After that is described the legislation, which frames the limits for pollutants suspended in the air. In the practical part is described the methods for calculation the geometry of cascade impactor, the design of three-stage impactor and finally the comparison with professional impactor. The designed impactor was then constructed and tested with wood burning stove as a source of particles.

This thesis analyses an occurrence of detected pollutant concentrations of nitrogen oxides, dust particles of the size od 10 and 2,5 m and ground ozone in years 2015-2019 in seven chosen locations in Brno agglomeration. In the introduction, the thesis describes basic terms, the issues of air pollution and relevant legislation. Individual pollutants are defined and also their effect on environment and human health. After that, the locations of Brno, for which the analysis is made, is specified. The dynamics of development of individual pollutants is shown through a statistical analysis of individual time lines. The analysis also focuses on the difference in the level of pollution during weekdays, holidays, seasons or rush hour. The quantities are also viewed from the point of view of the relevant air pollution limits and the influence of climatic factors, which significantly affect their concentrations.

Le démélange de sources pour la pollution de l'air peut être formulé comme un problème de NMF en décomposant la matrice d'observation X en le produit de deux matrices non négatives G et F, respectivement la matrice de contributions et de profils. Généralement, les données chimiques sont entâchées d'une part de données aberrantes. En dépit de l'intérêt de la communauté pour les méthodes de NMF, elles souffrent d'un manque de robustesse à un faible nombre de données aberrantes et aux conditions initiales et elles fournissent habituellement de multiples minimas. En conséquence, cette thèse est orientée d'une part vers les méthodes de NMF robustes et d'autre part vers les NMF informées qui utilisent une connaissance experte particulière. Deux types de connaissances sont introduites dans la matrice de profil F. La première hypothèse est la connaissance exacte de certaines composantes de la matrice F tandis que la deuxième information utilise la propriété de somme-à-1 de chaque ligne de la matrice F. Une paramétrisation qui tient compte de ces deux informations est développée et des règles de mise à jour dans le sous-espace des contraintes sont proposées. L'application cible qui consiste à identifier les sources de particules dans l'air dans la région côtière du nord de la France montre la pertinence des méthodes proposées. Dans la série d'expériences menées sur des données synthétiques et réelles, l'effet et la pertinence des différentes informations sont mises en évidence et rendent les résultats de factorisation plus fiables. / Source apportionment for air pollution may be formulated as a NMF problem by decomposing the data matrix X into a matrix product of two factors G and F, respectively the contribution matrix and the profile matrix. Usually, chemical data are corrupted with a significant proportion of abnormal data. Despite the interest for the community for NMF methods, they suffer from a lack of robustness to a few abnormal data and to initial conditions and they generally provide multiple minima. To this end, this thesis is oriented on one hand towards robust NMF methods and on the other hand on informed NMF by using some specific prior knowledge. Two types of knowlodge are introduced on the profile matrix F. The first assumption is the exact knowledge on some of flexible components of matrix F and the second hypothesis is the sum-to-1 constraint on each row of the matrix F. A parametrization able to deal with both information is developed and update rules are proposed in the space of constraints at each iteration. These formulations have been appliede to two kind of robust cost functions, namely, the weighted Huber cost function and the weighted αβ divergence. The target application-namely, identify the sources of particulate matter in the air in the coastal area of northern France - shows relevance of the proposed methods. In the numerous experiments conducted on both synthetic and real data, the effect and the relevance of the different information is highlighted to make the factorization results more reliable.

Main findings Although the data did not allow the inclusion of non-identified or “unknown” sources, allocation of the impact at the receptor point to the identified sources proved possible and useful in comparing individual tailings dams contributions. The No. 4 tailings dam has been identified as one of the major contributors to PM10 concentration at West Village. The average PM10 gravimetric concentration recorded at West Village was 18.4 μg/m3 and the concentration with the light scatter method was 15.4 μg/m3. Black carbon has been identified as significant contributor to overall PM10 mass concentrations with up to 34% in the winter season. Source appointment from receptor-based measurements has not been previously conducted at Driefontein Gold Mine. Source apportionment can make a valuable contribution in attempts to reduce air pollution. At a site where particulate matter is the predominant pollutant from a variety of potential sources, the contributions from the individual sources may be difficult to distinguish especially if the sources fall within a single category type with similar pollutant profiles. It would be useful to ascertain the individual contributions so that the effectiveness of existing control measures can be determined and areas where additional controls may be required can be identified. Too this effect, potential dust sources at and around a gold mine were identified. Samples of the dust sources were collected and analysed for their elemental compositions and abundances. A receptor point in a mine village was selected and equipped with an ESampler PM10 dust monitor as well as an aethalometer, the MicroAeth AE51 (MicroAeth). Monthly receptor samples were collected and analysed for their elemental concentrations. The elemental compositions of the potential sources and the concentrations at the receptor were statistically analysed for 12 periods of a month each to determine the possible contributions to the PM10 concentration at a mine village (West Village, Driefontein Mine, near Carletonville). Main conclusions Operational tailings dams can under, certain conditions contribute the major portion of fallout dust and PM10, even more than dormant tailings dams. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Chemical Engineering / Unrestricted

Portable mass spectrometry has become an important analytical tool for chemical detection and identification outside of a lab setting. Many variations and applications have been developed to benefit various fields of science. Membrane inlet mass spectrometry is used to allow certain analytes to pass into the mass spectrometer without breaking vacuum or letting in large particulate matter. These two important analytical tools have been applied to the detection of harmful chemicals in the air. Earth-based separations and reverse gas stack modelling are useful mathematical tools that can be used to locate the source of a chemical release by back calculation. Earth-based separations studies the way different molecules will diffuse and separate through the air. Reverse gas stack modelling refers to the concentration differences of a chemical in relation to its distance from its source. These four analytical techniques can be combined to quickly and accurately locate various harmful chemical releases. The same system can be used for many applications and has been tested to detect harmful chemicals within and air-handling system. The monitoring of air-handling systems can greatly reduce the threat of harm to the building occupants by detecting hazardous chemicals and shutting off the air flow to minimize human exposure.