Worst air pollution Unionville - Markham, today and tomorrow
Today (16 July): Air quality in Unionville 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 Unionville 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.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Unionville's air quality benefits from its historic village character with substantial tree canopy, offering somewhat better conditions than Markham's busier commercial corridors nearby.
Today - 16 July | Pollution peaks at 10:00
AQI:
Fair
35.5/100
PM2.5 (fine particles):
Good
10.1/100
PM10 (coarse particles):
Good
5.9/100
NO2 (nitrogen dioxide):
Good
7.1/100
O3 (ozone):
Fair
35.5/100
SO2 (sulfur dioxide):
Good
1.2/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.0/100
PM1 (ultrafine particles):
Good
8.0/100
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
8.1/100
PM10 (coarse particles):
Good
3.1/100
NO2 (nitrogen dioxide):
Good
7.6/100
O3 (ozone):
Fair
30.1/100
SO2 (sulfur dioxide):
Good
1.1/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.6/100
PM1 (ultrafine particles):
Good
6.7/100
Other Landmarks in Markham
Sports venues in Markham
Frequently Asked Questions
Is air quality bad in Unionville right now?
On 16 July 2026, overall air quality in Unionville 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 Unionville?
On 17 July 2026, air quality conditions in Unionville 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 Unionville?
Unionville sees clear seasonal swings in air quality, driven in part by its preserved heritage main street lined with century-old buildings. Spring planting and fall harvest can raise dust levels briefly, while summer heat occasionally pushes up ground-level ozone; winter usually brings the cleanest, calmest air of the year. The surrounding open land generally keeps air quality good outside of the busiest farming weeks.
Are air quality levels in Unionville 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.
Check air quality in other popular cities:
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