AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Biogenic Oxidation Products in a Mixed Forest: Their Concentrations, Reactivity, and Fates
GRAHAM FRAZIER, Chenyang Bi, Deborah McGlynn, Sally Pusede, Gabriel Isaacman-VanWertz, Virginia Tech
Abstract Number: 226 Working Group: Remote and Regional Atmospheric Aerosol
Abstract Volatile organic compounds emitted from biogenic sources represent the major source of reactive carbon into the atmosphere. Understanding the impacts of changing climate conditions on these emissions is important for predicting future particle and ozone concentration in addition to future climate conditions. In particular, intra- and inter-annual variability of ozone concentrations may impact the emissions of terpenes from vegetation in complex ways that are currently poorly understood by models. We present here early data from a new long-term field deployment to better understand the relationship between regional vegetation emissions, formation of particulate matter, and chemical reactions that change ozone concentrations. Detailed measurements of atmospheric composition were collected in and above a forest canopy in western Virginia representative of forest ecosystems in the southeastern US. This work focuses on understanding the chemical oxidation products of biogenic emissions by molecular characterization of the oxidation products of isoprene, monoterpenes, and sesquiterpenes, alongside measurements of precursor species. We deployed a semi-volatile thermal desorption aerosol gas chromatograph (SV-TAG) to measure the products of biogenic emissions. Particles and semi-volatile gases were collected and analyzed by gas chromatograph/mass spectrometry with hourly time resolution for a one-month period in the summer. We present concentrations of oxidation products and their precursors and discuss them in the context of particle sources, ecosystem function, and the ozone budget. In particular, we examine the extent to which these compounds may represent sources or sinks of oxidants, and what impact that role has on their fate in the environment.