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Atmos Chem Phys

Title:		Comprehensive atmospheric modeling of reactive cyclic siloxanes and their oxidation products
Author(s):		Janechek NJ; Hansen KM; Stanier CO;
Address:		"Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242, USA. IIHR Hydroscience and Engineering, University of Iowa, Iowa City, IA 52242, USA. Department of Environmental Science, Aarhus University, Roskilde, Denmark"
Journal Title:		Atmos Chem Phys
Year:		2017
Volume:		20170710
Issue:		13
Page Number:		8357 - 8370
DOI:		10.5194/acp-17-8357-2017
ISSN/ISBN:		1680-7316 (Print) 1680-7324 (Electronic) 1680-7316 (Linking)
Abstract:		"Cyclic volatile methyl siloxanes (cVMSs) are important components in personal care products that transport and react in the atmosphere. Octamethylcyclotetrasiloxane (D(4)), decamethylcyclopentasiloxane (D(5)), dodecamethylcyclohexasiloxane (D(6)), and their gas-phase oxidation products have been incorporated into the Community Multiscale Air Quality (CMAQ) model. Gas-phase oxidation products, as the precursor to secondary organic aerosol from this compound class, were included to quantify the maximum potential for aerosol formation from gas-phase reactions with OH. Four 1-month periods were modeled to quantify typical concentrations, seasonal variability, spatial patterns, and vertical profiles. Typical model concentrations showed parent compounds were highly dependent on population density as cities had monthly averaged peak D(5) concentrations up to 432ngm(-3). Peak oxidized D(5) concentrations were significantly less, up to 9ngm(-3), and were located downwind of major urban areas. Model results were compared to available measurements and previous simulation results. Seasonal variation was analyzed and differences in seasonal influences were observed between urban and rural locations. Parent compound concentrations in urban and peri-urban locations were sensitive to transport factors, while parent compounds in rural areas and oxidized product concentrations were influenced by large-scale seasonal variability in OH"
Keywords:
Notes:		"PubMed-not-MEDLINEJanechek, Nathan J Hansen, Kaj M Stanier, Charles O eng P30 ES005605/ES/NIEHS NIH HHS/ P42 ES013661/ES/NIEHS NIH HHS/ Germany 2017/07/01 Atmos Chem Phys. 2017 Jul; 17(13):8357-8370. doi: 10.5194/acp-17-8357-2017. Epub 2017 Jul 10"