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Atmos Chem Phys

Title:		On the sources and sinks of atmospheric VOCs: an integrated analysis of recent aircraft campaigns over North America
Author(s):		Chen X; Millet DB; Singh HB; Wisthaler A; Apel EC; Atlas EL; Blake DR; Bourgeois I; Brown SS; Crounse JD; de Gouw JA; Flocke FM; Fried A; Heikes BG; Hornbrook RS; Mikoviny T; Min KE; Muller M; Neuman JA; O'Sullivan DW; Peischl J; Pfister GG; Richter D; Roberts JM; Ryerson TB; Shertz SR; Thompson CR; Treadaway V; Veres PR; Walega J; Warneke C; Washenfelder RA; Weibring P; Yuan B;
Address:		"Department of Soil, Water, and Climate, University of Minnesota, Minneapolis-Saint Paul, MN, USA. NASA Ames Research Center, Moffett Field, CA, USA. Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria. Department of Chemistry, University of Oslo, Oslo, Norway. Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA. Department of Atmospheric Sciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA. Department of Chemistry, University of California, Irvine, Irvine, CA, USA. Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA. Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA. Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA. Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA. School of Earth Science and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea. United States Naval Academy, Chemistry Department, Annapolis, MD, USA. Institute for Environmental and Climate Research, Jinan University, Guangzhou, China"
Journal Title:		Atmos Chem Phys
Year:		2019
Volume:		20190717
Issue:		14
Page Number:		9097 - 9123
DOI:		10.5194/acp-19-9097-2019
ISSN/ISBN:		1680-7316 (Print) 1680-7324 (Electronic) 1680-7316 (Linking)
Abstract:		"We apply a high-resolution chemical transport model (GEOS-Chem CTM) with updated treatment of volatile organic compounds (VOCs) and a comprehensive suite of airborne datasets over North America to (i) characterize the VOC budget and (ii) test the ability of current models to capture the distribution and reactivity of atmospheric VOCs over this region. Biogenic emissions dominate the North American VOC budget in the model, accounting for 70 % and 95 % of annually emitted VOC carbon and reactivity, respectively. Based on current inventories anthropogenic emissions have declined to the point where biogenic emissions are the dominant summertime source of VOC reactivity even in most major North American cities. Methane oxidation is a 2x larger source of nonmethane VOCs (via production of formaldehyde and methyl hydroperoxide) over North America in the model than are anthropogenic emissions. However, anthropogenic VOCs account for over half of the ambient VOC loading over the majority of the region owing to their longer aggregate lifetime. Fires can be a significant VOC source episodically but are small on average. In the planetary boundary layer (PBL), the model exhibits skill in capturing observed variability in total VOC abundance (R (2) = 0:36) and reactivity (R (2) = 0:54). The same is not true in the free troposphere (FT), where skill is low and there is a persistent low model bias (~ 60 %), with most (27 of 34) model VOCs underestimated by more than a factor of 2. A comparison of PBL: FT concentration ratios over the southeastern US points to a misrepresentation of PBL ventilation as a contributor to these model FT biases. We also find that a relatively small number of VOCs (acetone, methanol, ethane, acetaldehyde, formaldehyde, isoprene C oxidation products, methyl hydroperoxide) drive a large fraction of total ambient VOC reactivity and associated model biases; research to improve understanding of their budgets is thus warranted. A source tracer analysis suggests a current overestimate of biogenic sources for hydroxyacetone, methyl ethyl ketone and glyoxal, an underestimate of biogenic formic acid sources, and an underestimate of peroxyacetic acid production across biogenic and anthropogenic precursors. Future work to improve model representations of vertical transport and to address the VOC biases discussed are needed to advance predictions of ozone and SOA formation"
Keywords:
Notes:		"PubMed-not-MEDLINEChen, Xin Millet, Dylan B Singh, Hanwant B Wisthaler, Armin Apel, Eric C Atlas, Elliot L Blake, Donald R Bourgeois, Ilann Brown, Steven S Crounse, John D de Gouw, Joost A Flocke, Frank M Fried, Alan Heikes, Brian G Hornbrook, Rebecca S Mikoviny, Tomas Min, Kyung-Eun Muller, Markus Neuman, J Andrew O'Sullivan, Daniel W Peischl, Jeff Pfister, Gabriele G Richter, Dirk Roberts, James M Ryerson, Thomas B Shertz, Stephen R Thompson, Chelsea R Treadaway, Victoria Veres, Patrick R Walega, James Warneke, Carsten Washenfelder, Rebecca A Weibring, Petter Yuan, Bin eng NNX14AP89G/NASA/ Germany 2019/07/01 Atmos Chem Phys. 2019 Jul; 19(14):9097-9123. doi: 10.5194/acp-19-9097-2019. Epub 2019 Jul 17"