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Atmos. Chem. Phys. Discuss., 10, 21259-21301, 2010
www.atmos-chem-phys-discuss.net/10/21259/2010/ doi:10.5194/acpd-10-21259-2010 © Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License. |
Global modeling of organic aerosol: the importance of reactive nitrogen
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
2School of GeoSciences, University of Edinburgh, Edinburgh, Scotland, UK
*now at: Department of Environmental Science, Policy and Management, University of California, Berkeley, California, USA
**now at: EOS Group, Department of Physics and Astronomy, University of Leicester, UK
Abstract. Reactive nitrogen compounds, specifically NOx and NO3, likely influence global organic aerosol levels. To assess these interactions, GEOS-Chem, a chemical transport model, is updated to include improved biogenic emissions (following MEGAN v2.1/2.04), a new organic aerosol tracer lumping scheme, aerosol from nitrate radical (NO3) oxidation of isoprene, and NOx-dependent terpene aerosol yields. As a result of significant nighttime terpene emissions, fast reaction of monoterpenes with the nitrate radical, and relatively high aerosol yields from NO3 oxidation, biogenic hydrocarbon-NO3 reactions are expected to be a major contributor to surface level aerosol concentrations in anthropogenically influenced areas such as the United States. By including aerosol from nitrate radical oxidation in GEOS-Chem, terpene aerosol approximately doubles and isoprene aerosol is enhanced by 30 to 40% in the Southeast United States. In terms of the global budget of organic aerosol, however, aerosol from nitrate radical oxidation is somewhat minor (slightly more than 3 Tg/yr) due to the relatively high volatility of organic-NO3 oxidation products. Globally, 69 to 88 Tg/yr of organic aerosol is predicted to be produced annually, of which 14–15 Tg/yr is from oxidation of monoterpenes and sesquiterpenes and 8–9 Tg/yr from isoprene.
Citation: Pye, H. O. T., Chan, A. W. H., Barkley, M. P., and Seinfeld, J. H.: Global modeling of organic aerosol: the importance of reactive nitrogen, Atmos. Chem. Phys. Discuss., 10, 21259-21301, doi:10.5194/acpd-10-21259-2010, 2010.