Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions
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 emission...
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doaj-24e1e8669dfe4a38a278c619d537bacb2020-11-25T00:57:38ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242017-03-011764305431810.5194/acp-17-4305-2017Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributionsS. H. Jathar0M. Woody1H. O. T. Pye2K. R. Baker3A. L. Robinson4Mechanical Engineering, Colorado State University, Fort Collins, CO 80525, USAUS Environmental Protection Agency, Research Triangle Park, NC 27711, USAUS Environmental Protection Agency, Research Triangle Park, NC 27711, USAUS Environmental Protection Agency, Research Triangle Park, NC 27711, USAMechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USAGasoline- 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.http://www.atmos-chem-phys.net/17/4305/2017/acp-17-4305-2017.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
S. H. Jathar M. Woody H. O. T. Pye K. R. Baker A. L. Robinson |
spellingShingle |
S. H. Jathar M. Woody H. O. T. Pye K. R. Baker A. L. Robinson Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions Atmospheric Chemistry and Physics |
author_facet |
S. H. Jathar M. Woody H. O. T. Pye K. R. Baker A. L. Robinson |
author_sort |
S. H. Jathar |
title |
Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions |
title_short |
Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions |
title_full |
Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions |
title_fullStr |
Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions |
title_full_unstemmed |
Chemical transport model simulations of organic aerosol in southern California: model evaluation and gasoline and diesel source contributions |
title_sort |
chemical transport model simulations of organic aerosol in southern california: model evaluation and gasoline and diesel source contributions |
publisher |
Copernicus Publications |
series |
Atmospheric Chemistry and Physics |
issn |
1680-7316 1680-7324 |
publishDate |
2017-03-01 |
description |
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. |
url |
http://www.atmos-chem-phys.net/17/4305/2017/acp-17-4305-2017.pdf |
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