Atmospheric emissions of ammonia (NH3) contribute to the formation of fine particles and nitrogen deposition that affect human and ecological health, yet little is known about NH3 transformation and fate. In this project, the research team intends to perform airborne and ground-based measurements of NH3 emitted from major cattle and dairy feedlots in the foothills of the Rocky Mountain National Park (RMNP). Results will help inform atmospheric chemists and test a forecasting tool for the downwind transport of reduced nitrogen into a sensitive ecosystem.

In this collaborative project between 2 institutions and 4 PIs, a 10-week field campaign is planned in the foothills of RMNP to determine (i) fluxes and deposition timescales of NH3 within 10 km downwind of large sources, and (ii) spatial distribution and partitioning of NHx ~100 km downwind of same sources. The main sampling platform is the University of Wyoming King Air (UWKA) research aircraft equipped with new measurement capabilities that allow for enhanced sampling strategies of gases and particulates. Gaseous species include reduced and oxidized nitrogen (NH3 and HNO3), methane (CH4), ethane (C2H6), carbon monoxide (CO), carbon dioxide (CO2) and water vapor (H2O), while particulates include aerosol concentration and size and their water-soluble species concentrations. CH4 and C2H6 allow to track the plume and distinguish between different source types. Integration of flight data with ground-based observations collected from mobile monitoring and existing sampling sites, provides a means to better interpret consistently available ground-based data in the future. Results will also contribute to improved representation of NH3 in transport models, help predict local air quality and inform stakeholders. Two graduate and several undergraduate students will obtain valuable hands-on experiences in a collaborative field campaign.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

National Science Foundation (NSF)
Division of Atmospheric and Geospace Sciences (AGS)
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Anne M. Johansen
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Colorado State University-Fort Collins
Fort Collins
United States
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