Air quality
Air quality in Saint-Constant today
Updated
Good (US AQI 27) Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. Model estimate for Thu, Nov 5, 8:00 pm (01:00 UTC).
Air quality in Saint-Constant right now
Right now the modelled US Air Quality Index for Saint-Constant, Quebec, Canada is 27, which falls in the "Good" band (up to 50). Air quality is satisfactory and poses little or no risk; a good time for outdoor activity.
The index is driven mainly by ozone, whose own sub-index is 27. Ozone usually peaks in the afternoon on sunny days and falls back after sunset.
PM2.5 is 3.4 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 3.4 µg/m³ against a guideline of 45; ozone is 54 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 9.1 µg/m³ (below the 24-hour guideline of 25).
Also this hour: carbon monoxide 185 µg/m³.
Live AQI, PM2.5, PM10 and ozone for Saint-Constant, Quebec, Canada, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 27 Good
- PM2.5
- 3.4 µg/m³ 0.2× WHO 24-h guideline
- PM10
- 3.4 µg/m³
- Ozone
- 54 µg/m³
- Dominant pollutant
- ozone sub-index 27
- Best hour tomorrow
- 11:00 am AQI 20
- European AQI
- 18
Saint-Constant AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 20 around Fri 11:00 am to 30 around Fri 8:00 pm, staying "Good" throughout.
The following day is expected to be worse, averaging about 35 against 24 for the next 24 hours.
| Local time (America/Toronto) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Thu 8:00 pm | 27 | Good | 3.4 | 3 | 54 |
| Thu 11:00 pm | 26 | Good | 4.1 | 4 | 57 |
| Fri 2:00 am | 26 | Good | 3.5 | 4 | 57 |
| Fri 5:00 am | 26 | Good | 3.5 | 4 | 45 |
| Fri 8:00 am | 23 | Good | 6 | 6 | 37 |
| Fri 11:00 am | 20 | Good | 3.7 | 4 | 53 |
| Fri 2:00 pm | 21 | Good | 3.9 | 4 | 55 |
| Fri 5:00 pm | 24 | Good | 11.7 | 12 | 31 |
| Fri 8:00 pm | 30 | Good | 16.1 | 16 | 6 |
| Fri 11:00 pm | 37 | Good | 9.7 | 10 | 18 |
| Sat 2:00 am | 39 | Good | 2 | 2 | 36 |
| Sat 5:00 am | 38 | Good | 2 | 2 | 36 |
| Sat 8:00 am | 36 | Good | 2 | 2 | 37 |
| Sat 11:00 am | 34 | Good | 1.5 | 2 | 50 |
| Sat 2:00 pm | 33 | Good | 1.6 | 2 | 55 |
| Sat 5:00 pm | 30 | Good | 2 | 2 | 52 |
| Sat 8:00 pm | 25 | Good | 1.8 | 2 | 50 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in Saint-Constant tomorrow
Between 6 am and 9 pm local time, the cleanest air tomorrow is forecast around 11:00 am (AQI 20, Good) and the worst around 9:00 pm (AQI 33). That is a swing of 13 points, so a run or walk around 11:00 am is noticeably better.
Saint-Constant vs the rest of Canada
Across 35 Canada cities we track, the average US AQI right now is 37 (Good). Saint-Constant at 27 is 10 points cleaner than average.
For context, the median across 2,646 cities worldwide is 64.
Air quality in cities near Saint-Constant
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Ville-Marie | 15 km | 32 | Good | 4.9 |
| Montréal | 16 km | 32 | Good | 4.9 |
| Le Plateau-Mont-Royal | 18 km | 32 | Good | 4.9 |
| Longueuil | 18 km | 32 | Good | 4.9 |
| Rosemont–La Petite-Patrie | 19 km | 32 | Good | 4.9 |
| Villeray–Saint-Michel–Parc-Extension | 22 km | 32 | Good | 4.9 |
| Mercier–Hochelaga-Maisonneuve | 23 km | 32 | Good | 4.9 |
| Laval | 25 km | 32 | Good | 4.9 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Saint-Constant, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.
Advice for sensitive groups
With the AQI at 27, there is no need for sensitive groups to change plans. People with asthma should still carry their reliever inhaler as usual.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Saint-Constant
Air quality elsewhere
Guides
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS).