Worst air pollution Byward Market - Ottawa, today and tomorrow

Today (16 July): Air quality in Byward Market is fair. O3 is fair; AQI and NO2 are medium; PM2.5, PM10, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 12:00 AM (NO2: 40.5/100).
Tomorrow (17 July 2026): Air quality in Byward Market is fair. All pollutants stay as today. Pollution peaks around 11:00 PM (NO2: 40.2/100). Airmine updates local air quality forecasts four times daily.

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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team

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Byward Market's air quality reflects its dense historic Ottawa market character, with vehicle traffic and market delivery activity contributing the primary local emissions to this compact downtown district.

Today - 16 July | Pollution peaks at 00:00

AQI:

Medium

40.5/100

PM2.5 (fine particles):

Good

10.5/100

PM10 (coarse particles):

Good

4.1/100

NO2 (nitrogen dioxide):

Medium

40.5/100

O3 (ozone):

Fair

36.7/100

SO2 (sulfur dioxide):

Good

5.9/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

5.0/100

PM1 (ultrafine particles):

Good

9.8/100

Levels show the poorest local air quality during the day

Tomorrow - 17 July | Pollution peaks at 23:00

AQI:

Medium

40.2/100

PM2.5 (fine particles):

Good

13.2/100

PM10 (coarse particles):

Good

4.8/100

NO2 (nitrogen dioxide):

Medium

40.2/100

O3 (ozone):

Fair

30.9/100

SO2 (sulfur dioxide):

Good

4.0/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

2.9/100

PM1 (ultrafine particles):

Good

11.3/100

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Frequently Asked Questions

Is air quality bad in Byward Market right now?

On 16 July 2026, overall air quality in Byward Market is fair. O3 is the main pollutant at 36.7/100. Pollution peaks around 12:00 AM (NO2: 40.5/100).

Will air quality be worse tomorrow in Byward Market?

On 17 July 2026, air quality conditions in Byward Market will be similar to today, with O3 forecast at fair at 30.9/100. Pollution peaks around 11:00 PM (NO2: 40.2/100).

When is air pollution at its worst in Byward Market?

Byward Market's air quality follows a seasonal rhythm tied to its dense mix of market stalls, restaurants and downtown Ottawa traffic. The warmest months typically see the poorest air quality, with heat and heavy traffic driving up smog levels on windless days, whereas fall and winter tend to bring cleaner, more variable conditions. The surrounding Greenbelt helps buffer some neighbourhoods, though downtown corridors still see the sharpest seasonal shifts.

Are air quality levels in Byward Market based on measurements or forecasts?

It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.

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Data provided by Airmine — Last update: 16 July 2026 at 10:33 CEST (Data is updated four times daily.)

This forecast is produced independently using Airmine's own atmospheric data and models.

Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.

For long term forecasts and maps, see the Airmine app