This dataset provides a summary of annual air pollution statistics from 1995 to the current available year for six air pollutants: * Carbon Monoxide * Oxides of Nitrogen (NO, NO2, NOx) * Ozone * Fine Particulate Matter (PM2.5) * Sulphur Dioxide * Total Reduced Sulphur The annual statistics include percentiles, mean, maximums and also indicate the number of times an air monitoring station exceeded an Ontario annual ambient air quality criteria, where applicable. This information is also available in the annual Air Quality in Ontario Reports. The hourly air pollutant concentration data is posted in near real time on the Air Quality Ontario website: http://www.airqualityontario.com/