Open Access Journal Article

Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions

by Jathar Shantanu H. 1 Woody Matthew 2 Pye Havala O. T. 2 Baker Kirk R. 2  and  Robinson Allen L. 3
1
Mechanical Engineering, Colorado State University, Fort Collins, CO 80525, USA
2
US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
3
Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
*
Author to whom correspondence should be addressed.
Atmos Chem Phys  17(6), 1; https://doi.org/10.5194/acp-17-4305-2017
Received: / Accepted: / Published Online:

Abstract

Gasoline- and diesel-fueled engines are ubiquitous sources of air pollution in urban environments. They emit both primary particulate matter and precursor gases that react to form secondary particulate matter in the atmosphere. In this work, we updated the organic aerosol module and organic emissions inventory of a three-dimensional chemical transport model, the Community Multiscale Air Quality Model (CMAQ), using recent, experimentally derived inputs and parameterizations for mobile sources. The updated model included a revised volatile organic compound (VOC) speciation for mobile sources and secondary organic aerosol (SOA) formation from unspeciated intermediate volatility organic compounds (IVOCs). The updated model was used to simulate air quality in southern California during May and June 2010, when the California Research at the Nexus of Air Quality and Climate Change (CalNex) study was conducted. Compared to the Traditional version of CMAQ, which is commonly used for regulatory applications, the updated model did not significantly alter the predicted organic aerosol (OA) mass concentrations but did substantially improve predictions of OA sources and composition (e.g., POA–SOA split), as well as ambient IVOC concentrations. The updated model, despite substantial differences in emissions and chemistry, performed similar to a recently released research version of CMAQ (Woody et al., 2016) that did not include the updated VOC and IVOC emissions and SOA data. Mobile sources were predicted to contribute 30–40 % of the OA in southern California (half of which was SOA), making mobile sources the single largest source contributor to OA in southern California. The remainder of the OA was attributed to non-mobile anthropogenic sources (e.g., cooking, biomass burning) with biogenic sources contributing to less than 5 % to the total OA. Gasoline sources were predicted to contribute about 13 times more OA than diesel sources; this difference was driven by differences in SOA production. Model predictions highlighted the need to better constrain multi-generational oxidation reactions in chemical transport models.

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Copyright: © by Shantanu H., Matthew, Havala O. T., Kirk R. and Allen L.. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) (Creative Commons Attribution 4.0 International License). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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ACS Style
Shantanu H., J.; Matthew, W.; Havala O. T., P.; Kirk R., B.; Allen L., R. Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions. Atmospheric chemistry and physics, 2022, 17, 1. https://doi.org/10.5194/acp-17-4305-2017
AMA Style
Shantanu H. J, Matthew W, Havala O. T. P, Kirk R. B, Allen L. R. Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions. Atmospheric chemistry and physics; 2022, 17(6):1. https://doi.org/10.5194/acp-17-4305-2017
Chicago/Turabian Style
Shantanu H., Jathar; Matthew, Woody; Havala O. T., Pye; Kirk R., Baker; Allen L., Robinson 2022. "Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions" Atmospheric chemistry and physics 17, no.6:1. https://doi.org/10.5194/acp-17-4305-2017

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