CART decision-tree statistical analysis and prediction of summer season maximum surface ozone for the Vancouver, Montreal, and Atlantic regions of Canada

Abstract

Prediction of daily maximum surface ozone (O3) concentration was begun by Environment Canada in the spring of 1993 for the Vancouver, Montreal, and Atlantic regions in order to advise the public of expected air quality. Surface and upper-air meteorological predictors and other predictors were matched with several years of observed daily maximum O3 concentrations for the months of May-September at air-monitoring sites in the three regions. A recent nonparametric data-driven tree-based analysis method known as CART (classification and regression trees) was used to analyze the data at each site. The decision trees can be used to predict maximum surface O3 concentrations if the predictor variables are forecast, thus providing an inexpensive site-specific model for forcasts and climate impact analysis. An estimation of performance with independent data was conducted for the Vancouver-lower Fraser River valley and Montreal regions for each of the five years 1988-92. -from Authors