Atmospheric and Oceanic Sciences Departmental Seminar Series
Ammonia’s Impact on Air Quality and Climate in Agricultural Regions and the Arctic
a talk by
Department of Chemistry, University of Toronto
Atmospheric ammonia (NH3) is an important precursor of particulate formation in atmosphere, and can impact air quality, climate and biodiversity. I will discuss field measurements made by my research group over the last five years that we are using the understand the impact of ammonia on atmospheric composition across a range of environments. In the Arctic atmosphere during summer, we identified an important role for migratory seabird colonies as a source of ammonia. Due to the relatively pristine atmosphere, this ammonia was found to exert a large influence on the number of cloud condensation nuclei, and ultimately on the regional climate forcing. Agricultural activities, including animal husbandry and fertilizer application, are the most important sources of ammonia on a global scale. Our aircraft and ground-based measurements in the Utah Winter Fine Particle Study in 2017 indicate that ammonia plays an important role in regulating mass loading of fine particles during air quality exceedance events. We find that current emission inventories are biased low, especially in regions where animal husbandry is the dominant source. Our eddy covariance flux measurements of ammonia above fertilized corn fields in the 2017 and 2018 growing seasons indicate that management practices and environmental conditions can control the magnitude, and even direction, of ecosystem-atmosphere ammonia flux.