Atmospheric Chemistry and Physics
DOI of Published Version
Cyclic volatile methyl siloxanes (cVMSs) are important components in personal care products that transport and react in the atmosphere. Octamethylcyclotetrasiloxane (D₄), decamethylcyclopentasiloxane (D₅), dodecamethylcyclohexasiloxane (D₆), 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 D₅ concentrations up to 432 ng m⁻³. Peak oxidized D₅ concentrations were significantly less, up to 9 ng m⁻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.
Granting or Sponsoring Agency
National Institute of Environmental Health Sciences through the University of Iowa Environmental Health Sciences Research Center (NIEHS/NIH P30ES005605) and the by Iowa Superfund Research Program, National Institute of Environmental Health Sciences (grant P42ES013661)
NIEHS/NIH P30ES005605, NIEHS P42ES013661
Journal Article Version
Version of Record
Published Article/Book Citation
Atmos. Chem. Phys., 17, 8357–8370, 2017 https://doi.org/10.5194/acp-17-8357-2017
Copyright (c) 2017 The Author(s)
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This work is licensed under a Creative Commons Attribution 3.0 License.