National outlookAir quality is currently very unhealthy at Grand Forks City Hall in British Columbia and unhealthy at several Ontario stations including Newmarket, Grand Bend, Barrie and Toronto Downtown, with PM2.5 levels ranging from 89 to 161 ug/m3. Over the next 48 hours, PM2.5 is expected to rise at Newmarket, Grand Bend and Barrie, reaching forecast highs of 129 to 179 ug/m3, while Grand Forks is forecast to ease to 71 ug/m3. Environment Canada reports 23 communities at high AQHI risk, with the highest risk levels of 11 in Grand Bend and Newmarket.
AI-generated summary of the latest observations and forecasts · updated Jul 18, 8:17PM
Forecast PM2.5 peaks from now, using the higher available model value
PM2.5 observations and smoke forecasts (µg/m³)
Stated times are Eastern Time Zone. FireSmoke is UBC's BlueSky dispersion model;
FireWork is ECCC's operational chemistry model. NowCast is the US EPA's smoke-responsive
weighted average of recent hours; the shaded bands are US EPA AQI category thresholds
(24-h basis, 2024 revision), which apply to NowCast — not to single hourly readings.
The dashed line marks now; forecasts extend beyond it.
Data table
| Time | Observed µg/m³ | FireSmoke µg/m³ | FireWork µg/m³ |
|---|