Effect of Precipitation on the Emissions of BVOCs and Their Potential Aerosol Formation

NAMRATA SHANMUKH PANJI, Deborah F. McGlynn, Laura E. R. Barry, Sally Pusede, Gabriel Isaacman-VanWertz, Virginia Tech

     Abstract Number: 450
     Working Group: Remote and Regional Atmospheric Aerosol

Abstract
Over thousands of reactive organic gases are continually emitted into the atmosphere and contribute to the global organic aerosol (OA) loading through complex photochemical oxidation pathways. A significant portion of these chemicals are emitted from biogenic sources during biochemical signaling, response to external stressors, or leaf senescence, etc. The amount of biogenic volatile organic compounds (BVOCs) released by plants during these processes is dictated by complex feedbacks that exist between plants and their environmental conditions. In particular, the effects of precipitation on a forest may drive complex interactions between the biosphere and atmosphere by removing ozone from the atmosphere and depositing it to the surface, and by potentially driving changes in emissions of reactive organic compounds. Consequently, while precipitation is generally considered as a mechanism to remove aerosols and oxygenated gases that might condense to form aerosol, it could also potentially increase aerosol formation indirectly by enhancing emissions of aerosol precursors. Therefore, a quantitative understanding of the impacts of precipitation on atmospheric composition is essential.

Hourly measurements of BVOC mixing ratios and meteorological data are available over three years from a measurement campaign at the Virginia Forest Laboratory (VFL), Fluvanna County, VA. In this study, we explore this interplay by analyzing hourly BVOC data before, during, and after rain events to quantify the impacts of rain events on aerosol formation over short and long time periods. Further, we present our investigations of the interannual variability in these relationships.