Executive Summary

Two graduate students (Mr. William Battye, Ph.D. (funded by the NASA funds); and Ms. Casey Bray, Ph.D. (funded by a combination of Kenan Institute funds and a MEAS TA funds) will be trained and mentored during the project. The results of the study will be widely disseminated via publications in peer- reviewed publications and presentations at professional conferences.

Based on the current emissions inventory, approximately 85 % of total US and Canada NH3 emissions are from agricultural sources (Aneja et al., 2009, Zbieranowski and Aherne, 2012), with about two-thirds due to animal husbandry and the remaining one-third due to volatilization from commercial nitrogen (N) fertilizer application. Increases in crop and animal farming (Aneja et al., 2008; Erisman et al. 2008) are resulting in shifts in NH3 emissions and mixing ratio patterns. By 2020, it is estimated that ammonia will be the largest single contributor to acidification, eutrophication, and secondary particulate matter in the US and Europe (Sutton et al., 2009). This increase in the relative role of ammonia in these processes results both from the expansion of agriculture and the success of US and European environmental policies in reducing sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions. Knowing the ammonia source distribution and mixing ratio with fine spatial and temporal resolution remain major challenges for the future. Thus, accurate representation of NH3 emissions, mixing ratio, and processes will be essential to assessing regulation needs and abatement strategies for PM2.5 and ammonia in the coming years. Satellite observations provides one such tool.

This proposed work addresses challenging issues and community needs associated with the effects of climate change on future atmospheric composition, and on air quality forecasting. Specifically, this work will allow us to (1) better understand the emission source of ammonia and PM2.5, and (2) mitigate the uncertainty in the trend of ammonia and PM2.5 over the source regions.