Short-range prediction of tropospheric ozone concentrations and exceedances for Baton Rouge, Louisiana

Previous research has been focused on improving forecasts of the daily maximum 1-h concentration of tropospheric ozone, which was based on criteria used by the U.S. Environmental Protection Agency (EPA). However, in 2001, EPA began implementing standards based on daily maximum 8-h mean concentrations rather than the former 1-h period. This study uses principal components analysis and multiple-regression analysis to forecast daily maximum 8-h ozone concentrations in the Baton Rouge, Louisiana, nonattainment zone. Although model performance for values at individual stations proved unsuccessful, likely because of the effects of local nonmeteorological conditions, a model for prediction of "exceedances" of the standards at three or more stations explains 46.2% of the variance in tropospheric ozone concentrations. Furthermore, a decision-making tree is proposed for short-range forecasting of whether an exceedance is expected. Results represent a first attempt to forecast 8-h peak tropospheric ozone concentrations for this region.