Pfister uses satellite and ground-based measurements, along with computer models, to study the sources and movements of air pollutants. She is particularly interested in wildfires, which emit gases and particles that can move thousands of miles through the atmosphere, affecting areas far downwind. Pfister analyzes the effect of wildfire emissions on local ozone levels, and she has quantified the impact that massive North American wildfires can have on air quality as far away as Europe. She also studies the intercontinental movement of pollution across the Pacific and how it impacts regional and local air quality over North America. Pfister works in NCAR’s Atmospheric Chemistry Division.