The Illness Cost of Air Pollution (ICAP) Model used by the Ontario Medical Association (OMA) requires annual average ambient concentrations for each Census Division (CD) and for each pollutant to be analysed in a given scenario. Using the latest monitoring results (2000-2002), DPRA estimated the concentrations of PM10, PM2.5, O3, NOx, SO2, SO4, and CO for each CD in Canada using the Kriging algorithm included in ArcInfo Workstation.

The selection of the best statistical form was based on how well the Kriging function fit the data. Once a method was selected based on the analysis of the semi-variogram, RMS error and visual inspection of the interpolated pollutant, a map was produced for each pollutant and overlayed with the population-weighted centroids for each CD. The pollutant concentrations for the each centroid was extracted and read into the ICAP program.