Organic nitrate aerosol formation via NO3 + biogenic volatile organic compounds in the southeastern United States
B. R. Ayres1,H. M. Allen1,2,D. C. Draper1,3,S. S. Brown4,R. J. Wild4,J. L. Jimenez5,6,D. A. Day5,6,P. Campuzano-Jost5,6,W. Hu5,6,J. de Gouw5,6,A. Koss5,6,R. C. Cohen7,K. C. Duffey7,P. Romer7,K. Baumann8,E. Edgerton8,S. Takahama9,J. A. Thornton10,B. H. Lee10,F. D. Lopez-Hilfiker10,C. Mohr10,11,P. O. Wennberg12,T. B. Nguyen12,A. Teng12,A. H. Goldstein13,K. Olson13,and J. L. Fry1B. R. Ayres et al. B. R. Ayres1,H. M. Allen1,2,D. C. Draper1,3,S. S. Brown4,R. J. Wild4,J. L. Jimenez5,6,D. A. Day5,6,P. Campuzano-Jost5,6,W. Hu5,6,J. de Gouw5,6,A. Koss5,6,R. C. Cohen7,K. C. Duffey7,P. Romer7,K. Baumann8,E. Edgerton8,S. Takahama9,J. A. Thornton10,B. H. Lee10,F. D. Lopez-Hilfiker10,C. Mohr10,11,P. O. Wennberg12,T. B. Nguyen12,A. Teng12,A. H. Goldstein13,K. Olson13,and J. L. Fry1
1Department of Chemistry, Reed College, Portland, OR, USA
2Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
3Department of Chemistry, University of California, Irvine, CA, USA
4Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
5Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
6Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
7Department of Chemistry, University of California at Berkeley, CA, USA
8Applied Research Associates, Inc., Research Triangle Park, NC, USA
9Department of Environmental Engineering, École polytechnique fédérale de Lausanne (EPFL), Switzerland
10Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA
11Karlsruhe Institute of Technology, Karlsruhe, Germany
12Division of Geological and Planetary Sciences and Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
13Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
1Department of Chemistry, Reed College, Portland, OR, USA
2Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
3Department of Chemistry, University of California, Irvine, CA, USA
4Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
5Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
6Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
7Department of Chemistry, University of California at Berkeley, CA, USA
8Applied Research Associates, Inc., Research Triangle Park, NC, USA
9Department of Environmental Engineering, École polytechnique fédérale de Lausanne (EPFL), Switzerland
10Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA
11Karlsruhe Institute of Technology, Karlsruhe, Germany
12Division of Geological and Planetary Sciences and Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
13Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
Received: 12 May 2015 – Discussion started: 16 Jun 2015 – Revised: 26 Oct 2015 – Accepted: 14 Nov 2015 – Published: 03 Dec 2015
Abstract. Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOCs) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that a nitrate radical (NO3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are correlated with increase in gas- and aerosol-organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol formation as measured by aerosol mass spectrometry and thermal dissociation laser-induced fluorescence suggests a molar yield of aerosol-phase monoterpene nitrates of 23–44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to BVOCs and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate-oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 1 % of the total organic nitrate in the aerosol phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading at a rate comparable to that of organic nitrate produced via NO3 + BVOCs.
This paper reports atmospheric gas- and aerosol-phase field measurements from the southeastern United States in summer 2013 to demonstrate that the oxidation of biogenic volatile organic compounds by nitrate radical produces a substantial amount of secondary organic aerosol in this region. This process, driven largely by monoterpenes, results in a comparable aerosol nitrate production rate to inorganic nitrate formation by heterogeneous uptake of HNO3 onto dust particles.
This paper reports atmospheric gas- and aerosol-phase field measurements from the southeastern...
