OVERVIEW
Air pollution kills – worldwide more than 7 million people per year. Our research focuses on better understanding the formation, transformation and properties of gas and particle-phase pollutants, helping to develop effective policy actions aimed at mitigating pollutant concentrations and their adverse effects. Current specific research topics are summarized below.
Air quality impacts of oil and gas development
(Collaboration between UT Austin ( Hildebrandt Ruiz, Allen, Misztal, Matsui, Peng), and George Mason University (Henneman)
Horizontal drilling and hydraulic fracturing have greatly increased the scale and rate of unconventional oil and gas development (UOGD) in the United States. Scientific evidence suggests that communities are exposed to air pollutants and noise from UOGD, and that these exposures adversely affect human health. There is a critical need for better characterization and understanding of these exposures.
UOGD operations are complex and heterogeneous, with equipment, operations and emissions varying significantly from site to site. These source differences, the multiple pollutants emitted from UOGD, and the atmospheric reactions that transform the emissions, make characterizing air pollutant exposures resulting from UOGD difficult. Predictive tools are needed in order to appropriately focus, and place in context, measurement campaigns to assess exposures.
As part of a study funded by HEI Energy we are developing a broadly applicable community model which can assess exposures to air pollutants from UOGD and inform future health studies. As part of this project, we are also conducting target field measurements on stationary and mobile platforms to evaluate and refine the model, to quantify pollutants not captured by the model, and to determine emission fingerprints of various sources. We will use the updated model to assess community exposures.
We are focusing on the Eagle Ford Shale (EFS) in south central Texas, a large oil and gas production region that includes the production of dry gas, wet gas and oil. This heterogeneity of production types makes the EFS a microcosm of UOGD sites throughout the United States. The final model can be used in other regions with appropriate input data. We also conducted measurements in the Permian Basin, and modeling in the Marcellus Shale.
Indoor air quality impacts of widespread disinfection
(Collaboration with Drs. Atila Novoselac and Pawel Misztal, UT Austin)
The COVID-19 pandemic has necessitated the wide-spread use of disinfectants without thorough studies on personal protection during disinfection, the longer-term indoor air quality effects, or human health impacts. Public buildings including schools and daycares are fogged periodically with hospital-grade disinfectants, especially as some school districts are pressured to open schools for in-person instruction in spite of the ongoing pandemic. There is no guidance on mask use during disinfection or indoor air quality remediation post disinfection, and there is little knowledge on health impacts due to disinfectant exposure.
We conducted experiments to measure air quality changes during disinfection and to observe the interaction between disinfectants and masks. Masks can decrease inhalation exposure to disinfection byproducts when concentrations are very high but can increase exposure when concentrations are lower.
Tropospheric chlorine chemistry
Hydroxyl (OH) and ozone (O3) are the most abundant atmospheric oxidants, but chlorine atoms (Cl) are much more reactive and can oxidize volatile organic compounds (VOC) extremely quickly. Cl can also initiate radical propagation pathways which generate OH as secondary radical. We conduct experiments on the formation of PM and ozone from Cl-initiated oxidation of several different hydrocarbon precursors, and to measure the production of reactive chlorine from heterogeneous chemistry on chloride containing particles. Current analysis focuses on the molecular composition of gas and particle-phase products, understanding reaction mechanisms, and quantifying the effects of Cl and OH.