Field measurements and recent advances in detection of NH3 and HNO3

Wednesday, 17 December 2014
Joseph R Roscioli, Scott C. Herndon, John B Nowak, Mark S Zahniser and David D Nelson, Aerodyne Research Inc., Billerica, MA, United States
Ammonia and nitric acid play important roles in aerosol, cloud, and OH chemistry. Presented here are results from several field studies of HNO3 and NH3 sources in the mid- and southwestern United States. Particular focus is paid to NH3 emissions from farming and feedlot operations, and airborne HNO3 measurements over the Denver Metro area. Accurately measuring these species' concentrations on a fast timescale has historically been complicated due to their tendency to slowly and irreversibly interact with instrument surfaces. Recent efforts aimed at mitigating these effects using new inlet technologies will be presented, with demonstrations of time responses of ~1 second for both NH3 and HNO3.