Worst air pollution Harrow, today and tomorrow
Today (16 July): Air quality in Harrow is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 3:00 PM (O3: 34.0/100).
Tomorrow (17 July 2026): Air quality in Harrow is medium. AQI improves to medium; O3 decreases to medium; all other pollutants stay as today. Pollution peaks around 4:00 PM (O3: 43.6/100). 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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Harrow's position in Harrow means air quality is mostly determined by local road traffic and the compact scale of the centre. The nearby A40 corridor contributes steady vehicle emissions that affect roadside readings. Light prevailing breezes usually ensure decent dispersal, so levels generally stay within the moderate range typical of UK towns.
Today - 16 July | Pollution peaks at 15:00
AQI:
Fair
34.0/100
PM2.5 (fine particles):
Good
7.8/100
PM10 (coarse particles):
Good
2.6/100
NO2 (nitrogen dioxide):
Good
3.4/100
O3 (ozone):
Fair
34.0/100
SO2 (sulfur dioxide):
Good
0.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.8/100
PM1 (ultrafine particles):
Good
7.4/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 16:00
AQI:
Medium
43.6/100
PM2.5 (fine particles):
Good
10.6/100
PM10 (coarse particles):
Good
3.6/100
NO2 (nitrogen dioxide):
Good
4.8/100
O3 (ozone):
Medium
43.6/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.2/100
PM1 (ultrafine particles):
Good
9.9/100
Pollen forecast in Harrow
View pollen forecastFrequently Asked Questions
Is air quality bad in Harrow right now?
On 16 July 2026, overall air quality in Harrow is fair. AQI is the main air quality indicator at 34.0/100. Pollution peaks around 3:00 PM (O3: 34.0/100).
Will air quality be worse tomorrow in Harrow?
On 17 July 2026, air quality conditions in Harrow will be better than today, with AQI forecast at medium at 43.6/100. Pollution peaks around 4:00 PM (O3: 43.6/100).
When is air pollution at its worst in Harrow?
Air quality in Harrow isn't the same all year round — it really shifts with the seasons. In deep winter, a lack of wind lets A40 traffic fumes and woodsmoke settle instead of blowing through. Summer's more of a mixed bag: ozone can spike in strong sun, but overall dispersion tends to be better than the depths of winter. The shoulder seasons generally bring the mildest readings of the year.
Are air quality levels in Harrow 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.
Want to see air quality forecasts for other cities in United Kingdom?
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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