Research Projects

Project at a Glance

Project Status: active

Title: Improving chemical mechanisms for ozone and secondary organic carbon

Principal Investigator / Author(s): Wexler, Anthony

Contractor: UC Davis

Contract Number: 12-312

Research Program Area: Atmospheric Processes

Topic Areas: Ambient Air Quality Stds, Chemistry & Reactivity, Modeling

Research Summary:

Despite improvements in urban air quality in recent years, unacceptable levels of ground-level ozone (O3) and atmospheric particulate matter (PM) continue to be a persistent problem in both urban and rural areas of California. To meet National Ambient Air Quality Standards, State and local agencies must develop State Implementation Plans and adopt additional regulations to control emissions of these pollutants and their precursors. It is therefore necessary to understand the physical and chemical processes that form these pollutants under various atmospheric conditions. Photochemical air quality models are the primary tool for determining the limiting precursors for various secondary pollutants in California air sheds. Chemical mechanisms are an integral part of these photochemical air quality models and must represent the state-of-the-science understanding of how O3 and other secondary pollutants are formed and their relationships to the primary pollutants emitted from different sources. This project will comprehensively update chemical mechanisms for predicting the formation of secondary organic carbon, assess the reactivity of volatile organic compounds (VOC) in Californiaís airsheds related to O3 formation, and evaluate 42 impacts of nitrogen pentoxide (N2O5) on secondary aerosol formation. The results will provide ARB with improved and more up-to-date mechanisms for gas-phase and secondary particulate matter PM prediction that underlie ARBís air quality planning effort.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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