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Gas and aerosol carbon in California: comparison of measurements and model predictions in Pasadena and Bakersfield.
Citation:
Baker, K., A. Carlton, Tad Kleindienst, J. Offenberg, M. Beaver, D. Gentner, A. Goldstein, P. Hayes, J. Jimrnez, J. Gilman, J. DeGouw, M. Woody, H. Pye, J. Kelly, M. Lewandowski, M. Jaoui, P. Stevens, W. Brune, Y. Lin, C. Robitschun, AND J. Surratt. Gas and aerosol carbon in California: comparison of measurements and model predictions in Pasadena and Bakersfield. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, Germany, 15:5243-5258, (2015).
Impact/Purpose:
The National Exposure Research Laboratory’s (NERL’s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA’s mission to protect human health and the environment. HEASD’s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA’s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
Co-located measurements of fine particulate matter (PM2.5) organic carbon (OC), elemental carbon, radiocarbon (14C), speciated volatile organic compounds (VOCs),and OH radicals during the CalNex field campaign provide a unique opportunity to evaluate the Community Multiscale Air Quality (CMAQ) model's representation of organic species from VOCs to particles. Episode average daily 23 h average 14C analysis indicates PM2.5 carbon at Pasadena and Bakersfield during the CalNex field campaign was evenly split between contemporary and fossil origins. CMAQ predicts a higher contemporary carbon fraction than indicated by the 14C analysis at both locations. The model underestimates measured PM2.5 organic carbon at both sites with very little (7% in Pasadena) of the modeled mass represented by secondary production, which contrasts with the ambient-based SOC/OC fraction of 63% at Pasadena.
URLs/Downloads:
CALNEX CMAQ AE6 CARBON PAPER REVISED V1WITH SUPPLEMENTAL ATTACHED.PDF (PDF, NA pp, 2213.951 KB, about PDF)Atmospheric Chemistry & Physics
