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Atmos. Chem. Phys. Discuss., 12, 17031-17086, 2012
www.atmos-chem-phys-discuss.net/12/17031/2012/ doi:10.5194/acpd-12-17031-2012 © Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License. |
Contributions of individual reactive biogenic volatile organic compounds to organic nitrates above a mixed forest
1Department of Chemistry, Purdue University, West Lafayette, IN, USA
2Department of Earth and Atmospheric 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. 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. Key BVOC-oxidant reactions were identified for future laboratory and field investigations into reaction rate constants, yields, and speciation of oxidation products. 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.
Citation: Pratt, K. A., Mielke, L. H., Shepson, P. B., Bryan, A. M., Steiner, A. L., Ortega, J., Daly, R., Helmig, D., Vogel, C. S., Griffith, S., Dusanter, S., Stevens, P. S., and Alaghmand, M.: Contributions of individual reactive biogenic volatile organic compounds to organic nitrates above a mixed forest, Atmos. Chem. Phys. Discuss., 12, 17031-17086, doi:10.5194/acpd-12-17031-2012, 2012.