Uncertainty in the estimation of the mixing height and its impact on ozone control strategies

摘要

Air pollutant concentrations predicted by the grid-based models are very sensitive to the mixing height. Determining the temporal evolution of the mixing height is a complex problem in air pollution modeling. In this paper, mixing heights derived from three algorithms, RAMMET-X, MIXEMUP, and CALMET are compared with those estimated from the wind profiler data. The results indicate significant differences in the temporal variation of the height of the mixing layer estimated from these methods. The impact of the uncertainties inherent to the estimation of the mixing height profile on the ozone concentrations predicted by the Urban Airshed Model (UAM-IV) is examined for a high ozone episode in July 1991 over the New York metropolitan area. The results reveal that the efficacy of controls on emissions of Volatile Organic Compounds (VOC) and Nitrogen Oxides (NOx) on ozone improvement in the New York metropolitan area is strongly affected by the choice of the mixing height methodology for the UAM-IV application.