AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Organic Aerosol from Nocturnal Oxidation of Biogenic VOCs: Results from Night Flights in the Southeast U.S. during SENEX 2013
STEVEN G. BROWN, Peter Edwards, Benjamin Ayres, Charles Brock, Joost de Gouw, Martin Graus, William P. Dube, Juliane L. Fry, Jessica Gilman, John Holloway, Ben H. Lee, Brian Lerner, Jin Liao, Felipe Lopez-Hilfiker, Ann M. Middlebrook, Kyung-Eun Min, J. Andrew Neuman, Ilana Pollack, James Roberts, Thomas Ryerson, Joel A. Thornton, Patrick Veres, Carsten Warneke, Robert Wild, Reed Wommack, NOAA ESRL
Abstract Number: 107 Working Group: Aerosol Chemistry
Abstract Oxidation of biogenic hydrocarbons, BVOC, by the nitrate radical, NO3, represents an important but highly uncertain mechanism by which anthropogenic (i.e., NO¬x) and biogenic emissions interact. For example, some model studies suggest large organic aerosol mass attributable to NO3-BVOC reactions, but estimates from different models vary widely. One key uncertainty is the nighttime oxidation of BVOC in the residual boundary layer, where a large mass of BVOC from the previous day’s emission resides, but where measurements are extremely sparse.
The SENEX campaign took place in June and July of 2013 in the southeast U.S., a region with large biogenic and anthropogenic emissions. There were several nighttime research flights of the NOAA P-3 aircraft that extensively sampled the residual layer, and that occasionally probed the nocturnal boundary layer during low approaches to airfields. Measurements included speciated BVOC, nighttime oxidants (NO3 and O3), BVOC oxidation products and aerosol mass and composition. This presentation will examine budgets for nighttime BVOC oxidation, particularly in the residual layer. It will address competition between NO3 and O3, the potential for organic nitrate and organic aerosol formation, and the changes in nighttime oxidative capacity that has resulted from declining anthropogenic emissions of NO¬x in the U.S.