Papers Published
Abstract:
An urban plume model is used to simulate the photochemistry of ozone (O-3) precursors and the concomitant generation of O-3 within an urban plume as it advects and mixes with the background atmosphere. On the basis of these calculations, we estimate the rates at which O-3 and its precursor compounds are exported to the background atmosphere and how these export rates are affected by various control strategies that might be implemented to reduce maximum O-3 concentrations within the urban plume. Two model cities with different chemical characteristics are considered: case 1, where peak O-3 concentrations during extreme air pollution episodes are more sensitive to nitrogen oxides (NOx = NO + NO2) and case 2, where peak O-3 concentrations during these episodes are more sensitive to volatile organic compounds(VOC). The model is first run for extreme meteorological conditions conducive to the generation of high O-3 concentrations to determine the most effective emission control strategies for reducing peak O-3 under these conditions. The model is then run for more typical meteorological conditions, to determine how these various emission control scenarios might affect the export of O-3 and its precursors from the urban to the rural and background atmosphere. The export of O-3 from the urban atmosphere is found to be more sensitive to NOx emissions, even for case 2 where VOC emission controls more effectively reduced peak O-3 during pollution episodes. The impact of VOC and NOx emission reductions on the export of primary and secondary O-3 precursor compounds is more complex, leading to reductions in the export of some species and enhancements in the export of others.