2381/20456 H. O. T. Pye H. O. T. Pye A. W. H. Chan A. W. H. Chan J. H. Seinfeld J. H. Seinfeld Michael P. Barkley Michael P. Barkley Global modeling of organic aerosol: The importance of reactive nitrogen (NO and NO) University of Leicester 2012 IR content 2012-10-24 09:08:44 Journal contribution https://figshare.le.ac.uk/articles/journal_contribution/Global_modeling_of_organic_aerosol_The_importance_of_reactive_nitrogen_NO_and_NO_/10115570 Abstract. Reactive nitrogen compounds, specifically NO[subscript: x] and NO[subscript: 3], 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 (NO[subscript: 3) oxidation of isoprene, and NO[subscript: x]-dependent monoterpene and sesquiterpene aerosol yields. As a result of significant nighttime terpene emissions, fast reaction of monoterpenes with the nitrate radical, and relatively high aerosol yields from NO[subscript: 3] oxidation, biogenic hydrocarbon-NO[subscript: 3] 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 (monoterpene + sesquiterpene) 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-NO[subscript: 3] oxidation products in the yield parameterization. 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.