In Canada, the Air Quality Health Index (AQHI) is a scale developed to help people understand what the current air quality means for your health. It is an initiative among Environment Canada, Health Canada and the provincial governments.

Environment Canada urges residents to limit their time outdoors. But even when inside, most buildings can only reduce airborne pollutants by half.

With various air quality indexes available, and as wildfire smoke becomes an increasing health risk, here’s what often goes into the decision to play sports or not — and how to make sense of air quality indexes when making your own decision.

Toronto and the GTA are under a heat wave and poor air quality warning issued by Environment Canada on July 14, 2025, due to wildfire smoke from northern Ontario. The poor air quality is expected to persist from Monday into Tuesday.

Environment Canada is warning of poor air quality and extreme heat in Toronto on Monday as southern Ontario braces for a week filled with hot and humid weather.