TY - JOUR
T1 - Surface and airborne measurements of organosulfur and methanesulfonate over the western United States and coastal areas
AU - Sorooshian, Armin
AU - Crosbie, Ewan
AU - Maudlin, Lindsay C.
AU - Youn, Jong Sang
AU - Wang, Zhen
AU - Shingler, Taylor
AU - Ortega, Amber M.
AU - Hersey, Scott
AU - Woods, Roy K.
N1 - Funding Information:
All data and results are available from the corresponding author (armin@email. arizona.edu). This research was supported in part by 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. The measurements during NiCE were funded by ONR grants N00014-10-1-0200 and N00014-10-1-0811. Some of the analyses and visualizations used in this study were produced with the Giovanni online data system, developed and maintained by the NASA GES DISC. We acknowledge the sponsors of the IMPROVE network and the Pima County Department of Environmental Quality for data. The authors acknowledge Haflidi Jonsson and Barbara Ervens for their helpful discussions.
Publisher Copyright:
© 2015. American Geophysical Union. All rights reserved.
PY - 2015
Y1 - 2015
N2 - 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 is also highest at coastal sites, with increasing values as a function of normalized difference vegetation index 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 submicrometer 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.
AB - 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 is also highest at coastal sites, with increasing values as a function of normalized difference vegetation index 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 submicrometer 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.
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U2 - 10.1002/2015JD023822
DO - 10.1002/2015JD023822
M3 - Article
AN - SCOPUS:84942154580
VL - 120
SP - 8535
EP - 8548
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 16
ER -