Index Geophysics

Global modeling of organic aerosol: the importance of reactive nitrogen (NOx and NO3)

Reactive nitrogen compounds, specifically NO_x 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 NO_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 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 (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-NO₃ 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.

Pye, H. O. T.

Chan, A. W. H.

Barkley, M. P.

Seinfeld, J. H.

2018-01-15

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application/pdf

10.5194/acp-10-11261-2010

https://acp.copernicus.org/articles/10/11261/2010/

eISSN: 1680-7324

eng