The goal of our project was to test our hypothesis that chemical reactions between pollutant gases and dust emitted from dried out lake beds, also known as playas, can generate reactive chlorine-containing gases that can lead to degraded air quality through the production of ozone, a criteria air pollutant regulated by the EPA. Through dedicated laboratory studies, we proved our hypothesis and further characterized how quickly and efficiently the reactions take place on playa dust. Further, we discovered that the playa dust mineralogy affected how much chlorine-containing gas was generated. Specifically, we found that competing chemical reactions with clays associated with playa dusts as well as the surface composition of playa dust particles played a key role in determining the outcome of our experiments. Our results are relevant for improving air quality models that aim to forecast pollutant exceedances. Traditional methods of modeling this chemistry rely on chemical methods that cannot account for competing reactions and surface composition. Because our findings are relevant for atmospheric particles (e.g., aerosols) other than playa dust, our work has broader implications for understanding how the chemical composition of aerosols from different sources affects their ability to contribute to ground-level concentrations of ozone and degraded air quality. Further, because the reactions that we studied are favorable in the wintertime, our work also contributes to a growing body of literature that aims to better understand recent observations of degraded wintertime air quality in regions such as Salt Lake City, which is also adjacent to a major dust emitting playa, the Great Salt Lake.

In addition to the scientific knowledge gained by this project, our work also resulted in several societal benefits. More broadly, our work contributed new knowledge regarding chemical pathways that enhance the production of ground-level ozone, a criteria air pollutant associated with negative health effects. Specifically, our work contributed to the early career training of a postdoctoral researcher, two PhD students, two undergraduate students, and a Master?s student. We also provided demonstrations of scientific concepts relevant to this work to middle school girls and first-generation college bound African and Latin American students. Due to COVID, our demonstrations were virtual in the last year of this project, increasing the reach of our outreach events to well over 1000 students.

Last Modified: 07/16/2021
Modified by: Cassandra Gaston