Worst air pollution Markham, today and tomorrow
Today (16 July): Air quality in Markham is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 10:00 AM (O3: 35.5/100).
Tomorrow (17 July 2026): Air quality in Markham is fair. All pollutants stay as today. Pollution peaks around 7:00 AM (O3: 30.1/100). 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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Markham's air quality reflects its position in the Greater Toronto Area's northern suburbs, with vehicle traffic on the 404 and 407 the primary local source amid the region's broader summer ozone challenges.
Today - 16 July | Pollution peaks at 10:00
AQI:
Fair
35.5/100
PM2.5 (fine particles):
Good
9.7/100
PM10 (coarse particles):
Good
5.7/100
NO2 (nitrogen dioxide):
Good
6.1/100
O3 (ozone):
Fair
35.5/100
SO2 (sulfur dioxide):
Good
1.0/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.0/100
PM1 (ultrafine particles):
Good
7.7/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 07:00
AQI:
Fair
30.1/100
PM2.5 (fine particles):
Good
7.8/100
PM10 (coarse particles):
Good
3.0/100
NO2 (nitrogen dioxide):
Good
6.6/100
O3 (ozone):
Fair
30.1/100
SO2 (sulfur dioxide):
Good
0.9/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.6/100
PM1 (ultrafine particles):
Good
6.4/100
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Frequently Asked Questions
Is air quality bad in Markham right now?
On 16 July 2026, overall air quality in Markham is fair. AQI is the main air quality indicator at 35.5/100. Pollution peaks around 10:00 AM (O3: 35.5/100).
Will air quality be worse tomorrow in Markham?
On 17 July 2026, air quality conditions in Markham will be similar to today, with AQI forecast at fair at 30.1/100. Pollution peaks around 7:00 AM (O3: 30.1/100).
When is air pollution at its worst in Markham?
Markham's air quality follows a seasonal rhythm tied to dense suburban development and proximity to Highway 404. Warmer months usually bring elevated ozone and haze as heat, sunlight and vehicle emissions interact, while cooler months bring a marked improvement, apart from occasional temperature inversions that trap pollutants near the surface overnight. Local monitoring stations typically flag the sharpest changes during still, hot afternoons in July and August.
Are air quality levels in Markham 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