Air Quality Ontario

The quality of our air directly impacts our health and the natural environment, so we want our air to be as clean as possible. The Ministry of the Environment and Climate Change works to protect and improve air quality through legislation, targeted programs, and partnerships with other jurisdictions.

The Ministry has a network of 39 ambient (outside) air monitoring stations across the province that collect real-time air pollution data. This information is communicated to the public through Ontario's new Air Quality Health Index (AQHI) and as hourly concentrations of each pollutant. The Air Quality Health Index replaced the Air Quality Index on June 24, 2015. For more information, see What is the Air Quality Health Index? The Air Quality Health Index and data collected from our monitoring stations are posted on this website every hour, 24 hours a day, seven days a week.

As part of a new partnership with Environment Canada, Air Quality Health Index values and forecasts will also be posted on the Environment Canada website, www.airhealth.ca. Each year, the ministry prepares an Air Quality Report to assess the state of air quality in Ontario based on the provincial Air Quality Health Index network.

Current AQHI Alerts

Air Quality Health Index Forecast: Low to Moderate Risk

AQHI Forecasts: Air Quality Health Index Forecast for Thursday night of low to moderate risk for the province of Ontario. For details, see current AQHI Forecast. What is an Air Quality Health Index Forecast?

Clear day in Toronto

Current and Forecast Air Quality Health Index (AQHI)

Hourly AQHI Reports: The AQHI is issued hourly and is a scale designed to help you understand what the quality of the air around you means to your health. It is based on the following pollutants in our air: Ozone (O3), Fine Particulate Matter (PM2.5), Nitrogen Dioxide (NO2). What is the AQHI?

Clear day with children

Local, Live and Historical Data

Real-Time Pollutant Data: The Ontario Ministry of the Environment and Climate Change reports real-time O3, PM2.5, NO2, Carbon Monoxide (CO), and Sulphur Dioxide (SO2) data in geographical, graphical and tabular formats every hour. See the newest results: Current Pollutant Concentrations.