Long-term exposure to ozone at high concentrations can harm human health, materials and ecosystems. Tropospheric ozone is formed via photochemical reactions and is nonlinearly dependent on its two major precursors: nitrogen oxides (NOx) and volatile organic compounds (VOCs). Effective ozone control strategies must focus on reducing the atmospheric emission of these precursor species. Substantial progress has been made in this regard, leading to improvements in air quality attributed to ozone reduction across the US

Atmospheric chemists categorize the interaction between ozone and its key anthropogenic precursors into NOx-limited, transition, and VOC-limited regimes. Ozone production is considered NOx-limited when the loss of hydrogen oxide radicals (HOX) primarily occurs due to the self-reaction of peroxy radicals, and is considered VOC-limited when the loss of HOx primarily occurs due to reactions between OH and NO2.

Through my research, I aim to develop effective policies and strategies to improve air quality and protect public health. I am specifically interested in tropospheric ozone reduction strategies.

Tropospheric ozone (O3) remains a pressing environmental and public health issue and is linked to respiratory and cardiovascular conditions, ultimately contributing to premature mortality. These risks are often unevenly distributed, disproportionately impacting communities with lower socioeconomic status and historically marginalized groups. We integrate our CAMx model results with the US EPA’s Environmental Justice Screening and Mapping Tool (EJSCREEN) to explore the correlation between pollution exposure and socioeconomic factors.

EJSCREEN provides detailed socioeconomic and demographic metrics, allowing us to identify and quantify exposure inequalities across different communities at a county level (Kuruppuarachchi et al., 2017). With this analysis, we reveal significant disparities in pollution exposure, highlighting the communities within the CONUS most affected by high levels of O3.

These findings will underscore the necessity for targeted policies and interventions to address environmental justice concerns. With this study, we enhance our understanding of air pollution exposure inequalities and demonstrate the value of combining advanced air quality models with socioeconomic data to inform effective policy making.

The overall goal of this work was to understand the extent of exfiltration of fine Particulate Matter (PM2.5) and Black Carbon (BC) from traditional cookstove aerosol emissions in Bhopal, India. In order to achieve this objective, multiple instruments including a Quartz Crystal Microbalance, an Aethalometer, an Optical Particle Sizer and a Flue Gas Analyser were used in this study.

Cookstove emissions were routed through a dilution tunnel (1:25 dilution ratio) prior to sampling. Exfiltration estimates were obtained for BC and PM2.5 from in situ measurements made in a controlled environment. The suite of instruments used in this study permitted the estimation of cookstove solid fuel (wood, cowdung, crop residue) emissions particle densities.

An ancillary goal of this thesis was to obtain estimates of lung function distress as a consequence of exposure to the aerosols resulting from the burning of a variety of solid fuels for cooking. This objective was achieved by utilising a two-pronged approach that consisted of administering surveys and making field measurements using spirometry.