Articles | Volume 12, issue 21
Atmos. Chem. Phys., 12, 10125–10143, 2012

Special issue: Community Atmosphere-Biosphere Interactions Experiment 2009...

Atmos. Chem. Phys., 12, 10125–10143, 2012

Research article 05 Nov 2012

Research article | 05 Nov 2012

Contributions of individual reactive biogenic volatile organic compounds to organic nitrates above a mixed forest

K. A. Pratt1, L. H. Mielke*,1, P. B. Shepson3,1,2, A. M. Bryan4, A. L. Steiner4, J. Ortega5, R. Daly5,***, D. Helmig5, C. S. Vogel6, S. Griffith7, S. Dusanter9,8,7, P. S. Stevens10,7, and M. Alaghmand1 K. A. Pratt et al.
  • 1Department of Chemistry, Purdue University, West Lafayette, IN, USA
  • 2Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
  • 3Purdue Climate Change Research Center, Purdue University, West Lafayette, IN, USA
  • 4Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI, USA
  • 5Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA
  • 6University of Michigan Biological Station, Pellston, MI, USA
  • 7School of Public and Environmental Affairs, Indiana University, Bloomington, IN, USA
  • 8Université Lille Nord de France, Lille, France
  • 9École des Mines de Douai, Douai, France
  • 10Department of Chemistry, Indiana University, Bloomington, IN, USA
  • *now at: School of Public and Environmental Affairs, Indiana University, Bloomington, IN, USA
  • **now at: Atmospheric Chemistry Division, Earth System Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
  • ***now at: Air Pollution Prevention and Control Division, National Risk Management Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC, USA

Abstract. Biogenic volatile organic compounds (BVOCs) can react in the atmosphere to form organic nitrates, which serve as NOx (NO + NO2) reservoirs, impacting ozone and secondary organic aerosol production, the oxidative capacity of the atmosphere, and nitrogen availability to ecosystems. To examine the contributions of biogenic emissions and the formation and fate of organic nitrates in a forest environment, we simulated the oxidation of 57 individual BVOCs emitted from a rural mixed forest in northern Michigan. Key BVOC-oxidant reactions were identified for future laboratory and field investigations into reaction rate constants, yields, and speciation of oxidation products. Of the total simulated organic nitrates, monoterpenes contributed ~70% in the early morning at ~12 m above the forest canopy when isoprene emissions were low. In the afternoon, when vertical mixing and isoprene nitrate production were highest, the simulated contribution of isoprene-derived organic nitrates was greater than 90% at all altitudes, with the concentration of secondary isoprene nitrates increasing with altitude. Notably, reaction of isoprene with NO3 leading to isoprene nitrate formation was found to be significant (~8% of primary organic nitrate production) during the daytime, and monoterpene reactions with NO3 were simulated to comprise up to ~83% of primary organic nitrate production at night. Lastly, forest succession, wherein aspen trees are being replaced by pine and maple trees, was predicted to lead to increased afternoon concentrations of monoterpene-derived organic nitrates. This further underscores the need to understand the formation and fate of these species, which have different chemical pathways and oxidation products compared to isoprene-derived organic nitrates and can lead to secondary organic aerosol formation.

Final-revised paper