Nitrous acid (HONO) observations during the Uintah Basin Wintertime Ozone Studies (UBWOS) and the Wintertime Investigation of Transport, Emission, and Reactivity (WINTER) study: sources, measurements interferences, and implications beyond.

Wednesday, 16 December 2015: 17:15
3010 (Moscone West)
Patrick R Veres1,2, James M Roberts3, Sergio Luiz Alvarez4, Timothy S Bates5, Steven S Brown3, Peter Edwards6, James H Flynn III4, Joost A De Gouw3, James E Johnson7, Ben H. Lee5, Barry L Lefer8, John Liggio9, Felipe Lopez-Hilfiker5, Patricia Quinn10, Jochen Stutz11, Joel A Thornton12, Jui Yi Tsai11, Jeremy J B Wentzell13, Robert J Wild14 and Bin Yuan3, (1)Earth System Research Laboratory, Chemical Sciences Division, Boulder, CO, United States, (2)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (3)NOAA Boulder, Boulder, CO, United States, (4)University of Houston, Houston, TX, United States, (5)University of Washington Seattle Campus, Seattle, WA, United States, (6)University of Leicester, Leicester, United Kingdom, (7)NOAA PMEL, Seattle, WA, United States, (8)NASA Headquarters, Washington, DC, United States, (9)Environment Canada Toronto, Toronto, ON, Canada, (10)NOAA Pacific Marine Environmental Laboratory, Seattle, WA, United States, (11)University of California Los Angeles, Los Angeles, CA, United States, (12)Univ Washington - Seattle, Seattle, WA, United States, (13)Environment Canada, Toronto, ON, Canada, (14)Colorado University/NOAA/ESRL, Boulder, CO, United States
Recent work has highlighted HONO as a strong daytime source of OH radicals though a general lack of consensus exists with respect to the sources and overall impact of HONO photolysis on daytime radical budgets. Improvements in atmospheric HOx and NOx budgets, and therefore daytime HONO constraints, are necessary to improve air quality control strategies in adversely affected regions. In this presentation HONO measurements made using multiple collocated instruments during the UBWOS 2013 and 2014 field studies will be discussed. These results suggest that our ability to measure HONO is heavily dependent on our understanding of sampling artifacts, measurement interferences, and background determinations. We also present mid-latitude tropospheric observations of HO2NO2, as high as 1.5 ppbv, that coincide with the observed maxima in daytime HONO. These coinciding observations of both HONO and HO2NO2 will be presented with a particular emphasis on potential vertical gradients, surface chemistry, and daytime budgets. Results of this work may be relevant to interpretation of HONO observations in a range of environments from clean arctic to relatively polluted urban summertime regions. Measurements of HONO from the Wintertime Investigation of Transport, Emission, and Reactivity (WINTER) project in 2015 will be shown for comparison.