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The Formation of Secondary Organic Aerosol from the Isoprene + OH Reaction in the Absence of NOx
Citation:
KLEINDIENST, T. E., M. LEWANDOWSKI, J. H. OFFENBERG, M. JAOUI, AND E. O. EDNEY. The Formation of Secondary Organic Aerosol from the Isoprene + OH Reaction in the Absence of NOx. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, Germany, 9(17):6541-6558, (2009).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL) 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:
The reaction of isoprene (C5H8) with hydroxyl radicals has been studied in the absence of nitrogen oxides (NOx) to determine physical and chemical characteristics of the secondary organic aerosol formed. Experiments were conducted using a smog chamber operated in a steady-state mode permitting measurements of moderately low aerosol levels. GC-MS analysis was conducted to measure methyl butenediols in the gas phase and polyols in the aerosol phase. Analyses were made to obtain several bulk aerosol parameters from the reaction including values for the organic mass to organic carbon ratio, the effective enthalpy of vaporization (Δ Heff >vapeff), the organic peroxide fraction, and the aerosol yield.
URLs/Downloads:
The Formation of Secondary Organic Aerosol from the Isoprene + OH Reaction in the Absence of NOx (PDF, NA pp, 7915 KB, about PDF)Atmospheric Chemistry and Physics
