The Ontario Ministry of the Environment, Conservation, and Parks has created the user-friendly website Air Quality Ontario in order to provide Ontarians with current Air Quality Index (AQI) readings, historical ambient air pollution data, air quality forecasts, and current pollutant concentrations, as well as information on actions that can be taken when a smog alert is issued.
Reports and forecasts of air quality (based on the AQI) can be browsed by city on the website, but downloadable datasets are also available. Users can download historical data in the form of hourly readings of various pollutants (Ground-level Ozone, Nitrous Oxides etc.). The datasets are provided by monitoring station location (e.g. "Hamilton West") in .csv format, which can be imported into Excel or GIS software. Also available from the website are "Smog Advisory Statistics", which give gives the dates on which "Smog Days" were declared and the areas in which they applied. These datasets are provided in .xls format, which can be converted to .csv format in Excel to be imported into a GIS program.
Please note that there is no geospatial data directly included in these datasets. If users are interested in performing geospatial analysis, the locations of the monitoring stations or affected areas must be manually added by the user. The website does provide the Lat-Long coordinates of each monitoring station when you download the hourly pollutant data for that station.
Air Quality of Ontario - Science Data Sets