Document Type

Article

Publication Date

5-17-2016

Publication Title

Atmospheric Chemistry and Physics

ISSN

1680-7324

Volume

16

Issue

9

DOI

http://dx.doi.org/10.5194/acp-16-5969-2016

Abstract

Formation of organic nitrates (RONO2) during oxidation of biogenic volatile organic compounds (BVOCs: isoprene, monoterpenes) is a significant loss pathway for atmospheric nitrogen oxide radicals (NOx), but the chemistry of RONO2 formation and degradation remains uncertain. Here we implement a new BVOC oxidation mechanism (including updated isoprene chemistry, new monoterpene chemistry, and particle uptake of RONO2) in the GEOS-Chem global chemical transport model with similar to aEuro-25aEuro- x aEuro-25aEuro-km(2) resolution over North America. We evaluate the model using aircraft (SEAC(4)RS) and ground-based (SOAS) observations of NOx, BVOCs, and RONO2 from the Southeast US in summer 2013. The updated simulation successfully reproduces the concentrations of individual gas- and particle-phase RONO2 species measured during the campaigns. Gas-phase isoprene nitrates account for 25-50aEuro-% of observed RONO2 in surface air, and we find that another 10aEuro-% is contributed by gas-phase monoterpene nitrates. Observations in the free troposphere show an important contribution from long-lived nitrates derived from anthropogenic VOCs. During both campaigns, at least 10aEuro-% of observed boundary layer RONO2 were in the particle phase. We find that aerosol uptake followed by hydrolysis to HNO3 accounts for 60aEuro-% of simulated gas-phase RONO2 loss in the boundary layer. Other losses are 20aEuro-% by photolysis to recycle NOx and 15aEuro-% by dry deposition. RONO2 production accounts for 20aEuro-% of the net regional NOx sink in the Southeast US in summer, limited by the spatial segregation between BVOC and NOx emissions. This segregation implies that RONO2 production will remain a minor sink for NOx in the Southeast US in the future even as NOx emissions continue to decline.

Comments

Jenny A. Fisher1,2, Daniel J. Jacob3,4, Katherine R. Travis3, Patrick S. Kim4, Eloise A. Marais3, Christopher Chan Miller4, Karen Yu3, Lei Zhu3, Robert M. Yantosca3, Melissa P. Sulprizio3, Jingqiu Mao5,6, Paul O. Wennberg7,8, John D. Crounse7, Alex P. Teng7, Tran B. Nguyen7,a, Jason M. St. Clair7,b, Ronald C. Cohen9,10, Paul Romer9, Benjamin A. Nault10,c, Paul J. Wooldridge9, Jose L. Jimenez11,12, Pedro Campuzano-Jost11,12, Douglas A. Day11,12, Weiwei Hu11,12, Paul B. Shepson13,14, Fulizi Xiong13, Donald R. Blake15, Allen H. Goldstein16,17, Pawel K. Misztal16, Thomas F. Hanisco18, Glenn M. Wolfe18,19, Thomas B. Ryerson20, Armin Wisthaler21,22, and Tomas Mikoviny21

1Centre for Atmospheric Chemistry, School of Chemistry, University of Wollongong, Wollongong, NSW, Australia
2School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW, Australia
3Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
4Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
5Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, USA
6Geophysical Fluid Dynamics Laboratory/National Oceanic and Atmospheric Administration, Princeton, NJ, USA
7Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
8Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
9Department of Chemistry, University of California at Berkeley, Berkeley, CA, USA
10Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA, USA
11Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
12Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
13Department of Chemistry, Purdue University, West Lafayette, IN, USA
14Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, USA
15Department of Chemistry, University of California Irvine, Irvine, CA, USA
16Department of Environmental Science, Policy, and Management, University of California at Berkeley, Berkeley, CA, USA
17Department of Civil and Environmental Engineering, University of California at Berkeley, Berkeley, CA, USA
18Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
19Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
20Chemical Sciences Division, Earth System Research Lab, National Oceanic and Atmospheric Administration, Boulder, CO, USA
21Department of Chemistry, University of Oslo, Oslo, Norway
22Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria
anow at: Department of Environmental Toxicology, University of California at Davis, Davis, CA, USA
bnow at: Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA and Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
cnow at: Department of Chemistry and Biochemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA

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