The Role of Oxidation of BVOCs in SOA Production in the Southeastern U.S.EPA Grant Number: R835409
Title: The Role of Oxidation of BVOCs in SOA Production in the Southeastern U.S.
Investigators: Bertman, Steve , Pratt, Kerri A , Seeley, John , Shepson, Paul , Starn, Tim
Institution: Western Michigan University , Oakland University , Purdue University , West Chester University of Pennsylvania
EPA Project Officer: Hunt, Sherri
Project Period: April 1, 2013 through March 31, 2015 (Extended to March 31, 2016)
Project Amount: $387,483
RFA: Anthropogenic Influences on Organic Aerosol Formation and Regional Climate Implications (2012) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Global Climate Change , Climate Change , Air
We are proposing to conduct a key set of measurements of ambient concentrations of a wide array of atmospheric volatile organic compounds and photoproducts as part of the Southern Oxidant & Aerosol Study (SOAS) during the summer of 2013. The overarching goal is to enable better understanding of interactions between the biosphere and the anthroposphere in the production of atmospheric organic nitrates and secondary organic aerosols. These interactions will be further investigated using 1-D and CMAQ models, as well as off-line aerosol chemistry measurements.
On-line field measurements will be made with complementary instruments: 1) a new custom-designed 2D-GC instrument capable of obtaining automated hourly measurements of speciated anthropogenic and biogenic VOCs and oxidation products, including organic nitrates, 2) a CIMS instrument that is capable of measuring organic nitrates within classes, including total isoprene nitrates, and other important SOA precursors such as N2O5, 3) PAN compounds by GC-ECD. In addition, 4) aerosol filter sampling will be utilized for off-line FTIR and LC-ESI-MS measurements of various oxidation products in the particle-phase. One-dimensional and regional air quality (CMAQ) modeling will be used to probe organic nitrate and SOA production, with comparisons to field measurements of the individual precursors.
We plan to test three key hypotheses: 1) organic nitrates are important aerosol precursors in the southeastern U.S.; 2) NO3 - BVOC reactions are an important organic nitrate production route, even for daytime; and 3) the relative contributions of anthropogenic and biogenic SOA production in the southeastern U.S. can be determined, to a first order, using speciated VOC data, measured/calculated oxidant concentrations, and laboratory rate constants and aerosol yields. The relative importance of individual VOCs and oxidants will be tested using our 1-D modeling approach, and reaction of NO3 with isoprene will be added to CMAQ as a SOA production pathway to evaluate its significance in the southeastern U.S. This effort will also support a range of specific questions posed by SOAS, including uncertainties in the distribution and drivers of VOC and BVOC emissions, the roles of specific individual VOCs and BVOCs in SOA production, and the role of organic nitrates and nighttime chemistry in the production of SOA. Pursuit of these goals will yield a better understanding of the interactions between the atmosphere and the biosphere. This will allow more effective strategies for management of pollution sources and natural areas that ensure protection of environmental and human health. We also aim to provide undergraduate students with meaningful experiences conducting hypothesis-driven field research.