10 µg/m³ NowCast — Moderate on the US EPA scale — the median across 2 monitors in Halifax Metro and Halifax County West. Individual monitors run 7–13 µg/m³, highest at Johnston Building. Environment Canada's Air Quality Health Index nearby is 3.
14 µg/m³ measured at Johnston Building, 0 km away, at Aug 06, 2:00PM.
Unusually sensitive people should consider reducing prolonged outdoor exertion.
Forecast concentrations stay near current levels over the next 48 hours.
No significant smoke is expected in the next 48 hours.
1–3 low · 4–6 moderate · 7–10 high · 10+ very high · Forecast squares are Environment Canada's official AQHI period maximums.
● Observed — hourly median · ● FireSmoke · ● FireWork · ● HRRR · ▬ range across monitors
Background bands (US EPA AQI, 24-h basis): ■ Good · ■ Moderate
| Model | Peak PM2.5 | Peak around |
|---|---|---|
| FireSmoke (UBC BlueSky) | 0 µg/m³ | Aug 06, 7:00PM |
| FireWork (ECCC) | 9 µg/m³ | Aug 07, 9:00AM |
| HRRR-Smoke (NOAA, 3 km) | 3 µg/m³ | Aug 06, 4:00PM |
Model values are for the ~10 km grid cell nearest Halifax; the two models are independent and often disagree — treat the higher value as the cautious planning number.
Observations and NowCast are total PM2.5 — wildfire smoke plus every other source — as regulatory monitors measure it, and FireWork models that same total. FireSmoke is a smoke-dispersion model: it estimates the wildfire contribution only, so it reads lower than the monitors whenever other sources matter. The map's optional plume layer is likewise fires-only.
Little smoke at the surface or overhead.
● At the ground · ● Overhead (if mixed down)
Overhead smoke dims the sun but is not what you breathe. The dashed line shows the surface level if the whole column mixed through the boundary layer — a worst case, not a forecast · Data: NOAA HRRR-Smoke
19-day record · 2 nearby monitors
| Model | Typical error | Tendency |
|---|---|---|
| FireWork | 2.1 µg/m³ | reads low 1.0 |
| FireSmoke | 4.1 µg/m³ | reads low 4.0 |
Mean absolute error and average tendency in µg/m³, from forecasts verified 0–6 hours ahead at monitors within 50 km. A short-range record, not a measure of how far ahead a model stays reliable. FireSmoke and HRRR model wildfire smoke only, so they read below the monitors whenever other sources of PM2.5 matter.
Open the live chart for Johnston Building — hourly observations, NowCast and both model forecasts.