CALGRID Photochemical Modeling of Air Quality Impacts of Alternative Transportation Fuel Use in Los Angeles

The National Renewable Energy Laboratory has been conducting a comprehensive program to quantify and assess the air quality impacts of the emissions of ozone precursors, air toxins, and greenhouse gases from alternative fuel vehicles. This program includes both an emissions estimation component and a photochemical modeling component to study three fuels: reformulated gasoline, compressed natural gas, and 85% methanol (M85). This report describes the use of the CALGRID model in the Los Angeles modeling domain using the State-Wide Air Pollution Research Center (SAPRC90) chemical mechanism and an early version of the SAPRC93 mechanism. A variety of conclusions can be drawn from the results of this study, including results from chemical mechanism testing; development of meteorological inputs; model evaluation and comparison; and the analyses of the impacts of the emissions scenarios. The report summarizes the study's major findings in these areas.