Composition, Concentrations, and Reactivity of Sesquiterpenes in the Southeastern US.

Abstract:

Sesquiterpenes are one class of volatile organic compounds emitted from biogenic sources. While this group of compounds represents only a small fraction of total biogenic emissions, they are highly reactive towards ozone and have high aerosol yields. However, due to difficulty measuring them, sesquiterpenoid emissions and their role in ozone budget is currently not well understood. We present data from a several field deployments in forested regions of the southeastern U.S. to characterize biogenic emissions during the spring and summer. The composition of organic aerosol and aerosol-forming organic gases were measured by a semi-volatile thermal desorption aerosol gas chromatography (SV-TAG) at a small farm at the western edge of the Richmond, VA, metropolitan area, representative of rural suburb interface in the southeastern US, and at a tower in a mixed forest near Charlottesville, VA. This work focuses on composition of sesquiterpenes, their role in the chemical loss of ozone, and their relation to total biogenic emissions. We examine these compounds in the context of nearby agricultural activity, biomass burning, and anthropogenic emissions.