Greater Toronto Air Quality & AQHI Observatory
Measured fine particulate matter (PM2.5), ground-level ozone (O3), and nitrogen dioxide (NO2) with the Air Quality Health Index across the Greater Toronto Area.
Health Notice: No Air Quality Health Index station is close enough to this city to report for it.
No alerts at last check, 12:40 a.m. ET
Air Quality Health Index
No Air Quality Health Index station is close enough to this city to report for it.
PM2.5 Fine Particulate
Aerodynamic ≤ 2.5 µm
Not reported at this station this hour.
O3 Ground Ozone
Tropospheric oxidant
Not reported at this station this hour.
NO2 Nitrogen Dioxide
Traffic & thermal plume
Not reported at this station this hour.
48-Hour Timeline & 24-Hour Predictive Curve
Observed readings from the past 48 hours through the current hour into Environment Canada's 24-hour forecast.
No history stored yet.
Not available.
No forecast stored.
Cross-Regional GTA Monitoring Stations
Comparative readings from Ontario Ministry (MECP) and federal monitoring sites across the region.
| Monitoring Station | AQHI Index | PM2.5 (µg/m³) | O3 (ppb) | NO2 (ppb) | Health Risk Category | Trend Sparkline |
|---|---|---|---|---|---|---|
TorontoMetro Region | 2 | 5 µg/m³ | 11 ppb | 17.2 ppb | Low Risk (1-3) | |
Toronto NorthYork Region | 2 | 3 µg/m³ | 16 ppb | 8.9 ppb | Low Risk (1-3) | |
Toronto EastDurham Region | 2 | 3 µg/m³ | 17 ppb | 7.8 ppb | Low Risk (1-3) | |
Toronto WestMetro Region | – | 7 µg/m³ | 11 ppb | 15.3 ppb | – | |
MississaugaPeel Region | 2 | 3 µg/m³ | 17 ppb | 6 ppb | Low Risk (1-3) | |
BramptonPeel Region | 1 | 3 µg/m³ | 18 ppb | 3.6 ppb | Low Risk (1-3) | |
OakvilleHalton Region | 2 | 3 µg/m³ | 20 ppb | 4 ppb | Low Risk (1-3) | |
BurlingtonHalton Region | 2 | 3 µg/m³ | 17 ppb | 6.7 ppb | Low Risk (1-3) | |
MiltonHalton Region | 2 | 3 µg/m³ | 19 ppb | 4.7 ppb | Low Risk (1-3) | |
NewmarketYork Region | 1 | 2 µg/m³ | 20 ppb | 3.5 ppb | Low Risk (1-3) | |
OshawaDurham Region | 1 | 2 µg/m³ | 19 ppb | 3.3 ppb | Low Risk (1-3) |
The Health Risk Calculation Model
Canada's AQHI combines a 3-part pollutant mixture rather than reporting the worst single reading:
About These Readings
The index comes from Environment and Climate Change Canada. Pollutant readings are from Air Quality Ontario, whose figures are automatically polled and have not undergone final verification.
The percentage bars compare a reading with the Canadian standard for that pollutant as a guide. The standards apply over longer periods than one hour.
Official Advice By Risk Level
- 1-3: Enjoy your usual outdoor activities.
- 4-6: Consider reducing or rescheduling strenuous outdoor activities if you have symptoms like coughing or throat irritation.
- 7+: Reduce or reschedule strenuous outdoor activities.
Data Source: Environment and Climate Change Canada. Licence. Pollutant readings: Ministry of the Environment, Conservation and Parks, Air Quality Ontario. Shown as published and may be out of date. This is not a warning service. IGTA is not affiliated with or endorsed by either government.
Brock
No Air Quality Health Index station is close enough to this city to report for it.
Canadian standard: 27 µg/m³
Photochemical generation
Canadian 1h standard: 60 ppb
No Air Quality Health Index station is close enough to this city to report for it.
GTA Regional Stations
Sorted by AQHI
Multi-Pollutant Cumulative Health Risk
The Canadian AQHI evaluates the combined health risk of three pollutants (O₃, PM₂.₅, and NO₂) rather than reporting the worst single reading.
About These Readings
Index from Environment and Climate Change Canada. Licence. Pollutants from Air Quality Ontario, automatically polled and not finally verified. Shown as published and may be out of date. This is not a warning service.