Composition and reactivity of volatile organic compounds in the South Coast Air Basin and  San Joaquin Valley of California

S. Liu; B. Barletta; R. S. Hornbrook; A. Fried; J. Peischl; J. Peischl; S. Meinardi; M. Coggon; M. Coggon; A. Lamplugh; A. Lamplugh; J. B. Gilman; G. I. Gkatzelis; G. I. Gkatzelis; G. I. Gkatzelis; C. Warneke; E. C. Apel; A. J. Hills; I. Bourgeois; I. Bourgeois; J. Walega; P. Weibring; D. Richter; T. Kuwayama; M. FitzGibbon; D. Blake

doi:10.5194/acp-22-10937-2022

Atmospheric Chemistry and Physics (Aug 2022)

Composition and reactivity of volatile organic compounds in the South Coast Air Basin and San Joaquin Valley of California

S. Liu,
B. Barletta,
R. S. Hornbrook,
A. Fried,
J. Peischl,
J. Peischl,
S. Meinardi,
M. Coggon,
M. Coggon,
A. Lamplugh,
A. Lamplugh,
J. B. Gilman,
G. I. Gkatzelis,
G. I. Gkatzelis,
G. I. Gkatzelis,
C. Warneke,
E. C. Apel,
A. J. Hills,
I. Bourgeois,
I. Bourgeois,
J. Walega,
P. Weibring,
D. Richter,
T. Kuwayama,
M. FitzGibbon,
D. Blake

Affiliations

S. Liu: Research Division, California Air Resources Board, Sacramento, CA 95814, USA
B. Barletta: Department of Chemistry, University of California, Irvine, CA 92697, USA
R. S. Hornbrook: Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO 80301, USA
A. Fried: Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80303, USA
J. Peischl: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
J. Peischl: NOAA Chemical Science Laboratory, Boulder, CO 80305, USA
S. Meinardi: Department of Chemistry, University of California, Irvine, CA 92697, USA
M. Coggon: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
M. Coggon: NOAA Chemical Science Laboratory, Boulder, CO 80305, USA
A. Lamplugh: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
A. Lamplugh: NOAA Chemical Science Laboratory, Boulder, CO 80305, USA
J. B. Gilman: NOAA Chemical Science Laboratory, Boulder, CO 80305, USA
G. I. Gkatzelis: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
G. I. Gkatzelis: NOAA Chemical Science Laboratory, Boulder, CO 80305, USA
G. I. Gkatzelis: now at: Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich GmbH, Jülich 52428, Germany
C. Warneke: NOAA Chemical Science Laboratory, Boulder, CO 80305, USA
E. C. Apel: Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO 80301, USA
A. J. Hills: Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO 80301, USA
I. Bourgeois: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
I. Bourgeois: NOAA Chemical Science Laboratory, Boulder, CO 80305, USA
J. Walega: Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80303, USA
P. Weibring: Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80303, USA
D. Richter: Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80303, USA
T. Kuwayama: Research Division, California Air Resources Board, Sacramento, CA 95814, USA
M. FitzGibbon: Research Division, California Air Resources Board, Sacramento, CA 95814, USA
D. Blake: Department of Chemistry, University of California, Irvine, CA 92697, USA

DOI: https://doi.org/10.5194/acp-22-10937-2022
Journal volume & issue: Vol. 22
pp. 10937 – 10954

Abstract

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Comprehensive aircraft measurements of volatile organic compounds (VOCs) covering the South Coast Air Basin (SoCAB) and San Joaquin Valley (SJV) of California were obtained in the summer of 2019. Combined with the CO, CH4, and NOx data, the total calculated gas-phase hydroxyl radical reactivity (cOHRTOTAL) was quantified to be 6.1 and 4.6 s−1 for the SoCAB and SJV, respectively. VOCs accounted for ∼ 60 %–70 % of the cOHRTOTAL in both basins. In particular, oxygenated VOCs (OVOCs) contributed >60 % of the cOHR of total VOCs (cOHRVOC) and the total observed VOC mixing ratio. Primary biogenic VOCs (BVOCs) represented a minor fraction (<2 %) of the total VOC mixing ratio but accounted for 21 % and 6 % of the cOHRVOC in the SoCAB and SJV, respectively. Furthermore, the contribution of BVOCs to the cOHRVOC increased with increasing cOHRVOC in the SoCAB, suggesting that BVOCs were important ozone precursors during high ozone episodes. Spatially, the trace gases were heterogeneously distributed in the SoCAB, with their mixing ratios and cOHR being significantly greater over the inland regions than the coast, while their levels were more evenly distributed in SJV. The results highlight that a better grasp of the emission rates and sources of OVOCs and BVOCs is essential for a predictive understanding of the ozone abundance and distribution in California.

Published in Atmospheric Chemistry and Physics

ISSN: 1680-7316 (Print); 1680-7324 (Online)
Publisher: Copernicus Publications
Country of publisher: Germany
LCC subjects: Science: Physics; Science: Chemistry
Website: http://www.atmospheric-chemistry-and-physics.net/

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