This project involves the deployment of novel mass spectrometric instrumentation for measuring intermediate-volatility organic compounds (IVOCs) and semivolatile organic compounds (SVOCs) during the Southern Oxidant and Aerosol Study (SOAS) scheduled for the summer of 2013. IVOCs and SVOCs may be important species in the formation and evolution of secondary organic aerosol--a major research focus of SOAS--but are poorly constrained, and not routinely measured in real time by commonly available techniques.
Deployment of the instrument to the SOAS ground field site will close a gap in the measurement of the inventory of organic species, and aid in overall carbon accounting. These measurements may be helpful for meeting several of the SOAS science objectives, including understanding the fluxes and oxidation of biogenic carbon, and the influences of anthropogenic emissions on biogenic aerosol.
This award will support measurements made by a graduate student, who will gain valuable experience in carrying out atmospheric chemistry fieldwork, working with researchers from a number of different institutions, including government and industry scientists.
Organic compounds make up a large fraction of atmospheric fine particulate matter, and therefore can have important impacts on global climate and human health. However the exact sources of organic aerosol (OA) are not well-understood, in part due to the very large number of organic compounds in the atmosphere and the complex chemical reactions that such compounds can undergo. In particular, two classes of atmospheric organic compounds – "intermediate volatility organic compounds" (IVOCs) and "semivolatile organic compounds" (SVOCs) – are thought to play important roles in OA chemistry, but are hard to study because they are lost to surfaces very easily. In previous work we developed a new instrument for the measurement and chemical characterization of these compounds. In this project we deployed that instrument as part of a large field campaign (the Southern Oxidant and Aerosol Study, SOAS), in Centreville, AL in the summer of 2013, with the goal of constraining the organic aerosol chemistry relevant to regions that are influenced by both anthropogenic and biogenic emissions. The instrument (which had to be modified to function in such a humid environment) made measurements of ambient IVOCs and SVOCs over several weeks of the campaign; these measurements will be combined with those from other instruments at the site to gain a comprehensive picture of the atmospheric organics at the site, and ultimately to better understand the chemistry underlying OA formation and evolution.
