Open AccessEffects of additional nonmethane volatile organic compounds, organic nitrates, and direct emissions of oxygenated organic species on global tropospheric chemistry
Author(s) -
Ito Akinori,
Sillman Sanford,
Penner Joyce E.
Publication year - 2007
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2005jd006556
Subject(s) - isoprene , peroxyacetyl nitrate , glyoxal , chemistry , troposphere , nox , methanol , volatile organic compound , environmental chemistry , tropospheric ozone , acetic acid , atmospheric chemistry , ozone , chemical transport model , photochemistry , organic chemistry , meteorology , combustion , polymer , physics , copolymer
This work evaluates the sensitivity of tropospheric ozone and its precursors to the representation of nonmethane volatile organic compounds (NMVOCs) and organic nitrates. A global 3‐D tropospheric chemistry/transport model (IMPACT) has been exercised initially using the GEOS‐Chem chemical reaction mechanism. The model was then extended by adding emissions and photochemical reactions for aromatic and terpenoid hydrocarbons, and by adding explicit representation of hydroxy alkyl nitrates produced from isoprene. Emissions of methanol, phenol, acetic acid and formic acid associated with biomass burning were also added. Results show that O 3 increases by 20% in most of the troposphere, peroxyacetyl nitrate (PAN) increases by 30% over much of the troposphere and OH increases by 10%. NO x (NO + NO 2 ) decreases near source regions and increases in remote locations, reflecting increased transport of NO x away from source regions by organic nitrates. The increase in O 3 was driven largely by the increased role of PAN as a transporter of NO x and by the rerelease of NO x from isoprene nitrates. The increased PAN production was associated with increases in methyl glyoxal and hydroxyacetone. Comparison with measured values show reasonable agreement for O 3 and PAN, but model measurement agreement does not either improve or degrade in the extended model. The extended model shows improved agreement with measurements for methanol, acetic acid and peroxypropional nitrate (PPN). Results from the extended model were consistent with measured alkyl nitrates and glycolaldehyde, but hydroxyacetone and methyl glyoxal were overestimated. The latter suggests that the effect of the isoprene nitrates is somewhat smaller than estimated here. Although the model measurement comparison does not show specific improvements with the extended model, it provides a more complete description of tropospheric chemistry that we believe is important to include.