Air quality in Markham
Most recent reading from the official reporting area covering Markham.
Preliminary readings from official networks, not fully validated. For health decisions follow your doctor and your local environmental agency.
AQHI
1.6
Low (1 to 3)
Toronto East · 10/16/26, 12:00 AM UTC
What to do
Low (1 to 3)
Normal outdoor activity.
AQHI
| Range | What to do |
|---|---|
| Low (1 to 3) | Normal outdoor activity. |
| Moderate (4 to 6) | People with symptoms may ease off outdoors. |
| High (7 to 10) | Sensitive groups should reduce or reschedule outdoor activity. |
| Very high (above 10) | Everyone should reduce outdoor exertion. |
Data from 10/16/26, 1:00 AM UTC
- Environment and Climate Change Canada — AQHILicence: ECCC End-use Licence (uso livre com citação da fonte) · Credit: Environment and Climate Change Canada
- GeoNames cities15000Licence: CC BY 4.0 · Credit: Dados de cidades: GeoNames (CC BY 4.0)
- Dados de cidades: GeoNames (CC BY 4.0)
How to read these numbers
The value is preliminary: networks publish a reading within about an hour and validate it later. It is good for deciding whether to go running today, not for legal comparison between years.
Frequently asked questions
- What is the air quality in Markham right now?
- The large number at the top is the latest reading from the reporting area that includes Markham, with the observation time beside it.
- What about tomorrow?
- Where the agency publishes a forecast, it appears in the day table. Forecasts are made by the network’s own meteorologists with a dispersion model.