The atmospheric electrical conductivity as an air pollution indicator was investigated through correlation analyses based on 2 years of daily averaged observations of the atmospheric electrical conductivity, the weather classification index, and the concentrations of aerosol particles, carbon monoxide, sulfur dioxide, and nitrogen dioxide at a single site in downtown Toronto from 1973 to 1974. The main findings are the following: (1) The electrical conductivity was negatively and almost linearly correlated to the individual pollutant concentrations. (2) The effects of the individual gaseous pollutants (i.e., carbon monoxide, sulfur dioxide, and nitrogen dioxide) on the electrical conductivity were superimposible with unequal weighting factors. (3) The multicorrelation of the electrical conductivity versus the superimposed concentration of the gaseous pollutants and the particulate pollutant concentration (i.e., aerosol particles) was significant, suggesting that the atmospheric electrical conductivity can be used as a composite air pollution indicator for detecting total air pollution. (4) The weather conditions did not seem to have any significant impact on the above correlation, although they had influenced both electrical conductivity and pollutant concentrations. ¿ American Geophysical Union 1996