AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Impact of Ammonia on Dynamics of Anthropogenic SOA Formation and Composition
MALLORY HINKS, Julia Montoya, Sergey Nizkorodov, Jeremy Horne, Donald Dabdub, University of California, Irvine
Abstract Number: 228 Working Group: Aerosol Chemistry
Abstract Ammonia enters the atmosphere through both natural and anthropogenic processes, with agriculture representing a significant emission source. The U.S. Department of Commerce estimated that 8.7 million metric tons of ammonia were produced in the U.S. in 2013 alone. This work investigates the effect that ammonia has on secondary organic aerosol (SOA) formation, optical properties, and composition through a combination of laboratory experiments and airshed modeling. We generate SOA via photoxidation of various precursors (toluene, n-hexadacane) in the Nizkorodov Lab smog chamber. These freshly produced SOA are then exposed to ammonia and the particle growth and VOC concentration is monitored. Samples of the SOA after addition of ammonia are collected and the nitrogen content is analyzed by DART-MS (Direct Analysis in Real Time Mass Spectrometry). The experimental results from this study will be incorporated into two models: 1) the UCI-CIT model, an airshed model that contains comprehensive SOA chemistry for the South Coast Air Basin of California and 2) a coupled meteorological-air quality model for continental-scale modeling of the U.S. The combination of comprehensive experimental and modeling studies will evaluate the impact of NH3 on SOA formation, optical properties, and composition and ultimately air quality and climate.