Meteorological phenomena such as heat waves, stagnation episodes, and the jet stream impact air quality and have been the subject of intense focus due to the potential ways climate change may impact them. Yet, there are often gaps in the community’s understanding of what links these meteorological features to surface-level pollution during the present-day and the spatial scales and timescales over which the relationships apply. Using chemical transport models, observations, and reanalyses, I have demonstrated the importance of the jet stream in regulating surface-level ozone pollution and shown weak connections between stagnation and ozone and particulate pollution. These results serve as a prerequisite for future studies aimed at understanding climate-driven impacts on air quality.

Global chemical transport models are the primary tool I use to understand air pollution, and I have extensive experience with GEOS-Chem and the Global Modeling Initiative chemical transport model. My work has gone beyond simply running and evaluating the models and has isolated specific processes within the models’ representation of meteorological, emissions, and chemistry. For example, I have quantified how increased NOx emissions on hot days due to air conditioner usage impacts ozone in the Eastern U.S. and isolated the temperature dependence of chemical kinetics to uncover what drives the ozone-temperature relationship. Recently, I have also used chemical transport models to diagnose jet stream-driven transport using idealized tracers. 

There is a legacy of environmental injustices on certain demographic groups in the U.S, often communities of color that lack upward mobility. Earth observing satellites such as the TROPOspheric Monitoring Instrument (TROPOMI) have unprecedented spatial resolution, allowing me to characterize exposure to pollutants such as nitrogen dioxide neighborhood by neighborhood to show that communities with higher racial diversity, lower income, and lower education attianment face higher exposures to nitrogen dioxide. I’ve also used these satellite retrievals to explore how the dramatic changes in human behavior unique to the pandemic-related lockdowns lead to large improvements in exposure for certain demographic groups. This research may be useful for future development of environmental policies aimed at reducing air pollution and minimizing health disparities.