Impacts of organic nitrate chemistry on NOx and O3 in California: Model results and comparisons to observations
Abstract
Organic nitrates, formed by a minor channel of the NO + RO2 reaction, represent a termination step of ozone production. Organic nitrate formation becomes most significant in the cross-over regime between NOx saturated (VOC limited) and NOx limited ozone production and, therefore, may have a significant impact on ozone photochemistry in urban outflows. Although numerous observations show that organic nitrates can represent a significant fraction (up to ~20%) of oxidized nitrogen, current regional chemistry models contain an inadequate representation of organic nitrates. We have developed a more realistic parameterization of organic nitrate chemistry that treats monofunctional, multifunctional saturated, multifunctional unsaturated, aromatic, isoprene, and monoterpene nitrates as unique model species with appropriate lifetimes and NOx recycling efficiencies. This chemistry has been incorporated into the WRF-Chem three dimensional regional chemistry model. Using a combination of model results and organic nitrate observations from ground and airborne measurements, we investigate how organic nitrate concentration and composition vary throughout California. Additionally, we analyze how organic nitrate formation impacts NOx lifetime and ozone production.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.A23B0150B
- Keywords:
-
- 0317 ATMOSPHERIC COMPOSITION AND STRUCTURE / Chemical kinetic and photochemical properties;
- 0345 ATMOSPHERIC COMPOSITION AND STRUCTURE / Pollution: urban and regional;
- 0365 ATMOSPHERIC COMPOSITION AND STRUCTURE / Troposphere: composition and chemistry