Events & Seminars > Event Details

Where:

4:00 pm
Room 304, Chemistry Building

Observational constraints on the anthropogenic sources, chemistry, and air quality and climate impacts of atmospheric nitrogen oxides

Speaker:

Professor Sally Pusede
Department of Environmental Sciences, University of Virginia

Hosted by: Professor Kevin Lehmann

Atmospheric nitrogen oxides affect global climate, air quality, and ecosystem nutrient cycling. For example, nitrous oxide (N2O) is a potent, long-lived greenhouse gas (lifetime ~ 100 years), and reactive nitrogen oxides, including NOx (≡ NO + NO2) and its chemical products, regulate the oxidative capacity of the troposphere. Nitrogen oxides are emitted though various anthropogenic processes with key uncertainties remaining in their sources and chemistry. In this talk, I present a series of in situ observational analyses investigating the emissions, chemistry, and drivers of change that influence the abundance and impacts of nitrogen oxides in atmosphere. First, I describe biogeochemical drivers of N2O emission during rice planting, including chemically reactive organic co-emissions. Second, I use vertical aircraft profiles of N2O, exploiting daily variation in near-surface atmospheric mixing, to quantify and apportion N2O emissions in a polluted agricultural region. Third, I discuss NOx chemistry occurring in atmospheric nocturnal residual layers and contributing to aerosol nitrate air pollution at the surface. To conclude, I consider long-term changes in emissions and chemistry driven by temperature and steep U.S.-wide NOx reductions.

Sally Pusede is an Assistant Professor in the Department of Environmental Sciences at the University of Virginia. She is an atmospheric chemist with broad interests in air quality, climate, and atmosphere-biosphere interactions. Her research group makes measurements at the Earth’s surface and from onboard aircraft in diverse locations, including polluted cities, agricultural areas, and within forest canopies. She focuses on the role of reactive nitrogen in chemical oxidation mechanisms and emissions of the greenhouse gas nitrous oxide. Her research group works to find solutions to atmospheric problems that adversely affect human health and ecosystems.