Surface and Airborne Measurements of Organosulfur and Methanesulfonate Over the Western United States and Coastal Areas
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Authors
Sorooshian, Armin
Crosbie, Ewan
Maudlin, Lindsay C.
Youn, Jong-Sang
Wang, Zhen
Shingler, Taylor
Ortega, Amber M.
Hersey, Scott
Woods, Roy K.
Subjects
Advisors
Date of Issue
2015
Date
Publisher
Language
Abstract
This study reports on ambient measurements of organosulfur (OS) and methanesulfonate (MSA)
over the western United States and coastal areas. Particulate OS levels are highest in summertime,
and generally increase as a function of sulfate (a precursor) and sodium (a marine tracer) with
peak levels at coastal sites. The ratio of OS to total sulfur (TS) is also highest at coastal sites, with
increasing values as a function of Normalized Difference Vegetation Index (NDVI) and the ratio
of organic carbon to elemental carbon. Correlative analysis points to significant relationships
between OS and biogenic emissions from marine and continental sources, factors that coincide
with secondary production, and vanadium due to a suspected catalytic role. A major OS species,
methanesulfonate (MSA), was examined with intensive field measurements and the resulting data
support the case for vanadium’s catalytic influence. Mass size distributions reveal a dominant
MSA peak between aerodynamic diameters of 0.32—0.56 μm at a desert and coastal site with
nearly all MSA mass (≥ 84%) in sub-micrometer sizes; MSA:non-sea salt sulfate ratios vary
widely as a function of particle size and proximity to the ocean. Airborne data indicate that
relative to the marine boundary layer, particulate MSA levels are enhanced in urban and
agricultural areas, and also the free troposphere when impacted by biomass burning. Some
combination of fires and marine-derived emissions leads to higher MSA levels than either source
alone. Finally, MSA differences in cloud water and out-of-cloud aerosol are discussed.
Type
Article
Description
The article of record as published may be found at http://dx.doi.org/10.1002/2015JD023822
Series/Report No
Department
Organization
Naval Postgraduate School (U.S.)
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NPS Report Number
Sponsors
Funding
Grant 2 P42 ES04940–11 from the National Institute of Environmental Health Sciences
(NIEHS) Superfund Research Program, NIH, and the Center for Environmentally Sustainable Mining through TRIF
Water Sustainability Program funding at the University of Arizona
ONR grants N00014-10-1-0200 and N00014-10-1-0811
ONR grants N00014-10-1-0200 and N00014-10-1-0811
Format
Citation
Sorooshian, Armin, et al. "Surface and airborne measurements of organosulfur and methanesulfonate over the western United States and coastal areas." Journal of Geophysical Research: Atmospheres. v.120 no.16 (2015): pp. 8535-8548.
Distribution Statement
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.