Worst air pollution Harrow, today and tomorrow
Today (9 August): Air quality in Harrow is poor. AQI and O3 are poor; PM2.5 and PM1 are fair; PM10, NO2, SO2, CO, and HCHO are good. Pollution peaks around 3:00 PM (O3: 60.4/100).
Tomorrow (10 August 2026): Air quality in Harrow is fair. AQI improves to fair; PM2.5 decreases to good; O3 decreases to fair; PM1 decreases to good; all other pollutants stay as today. Pollution peaks around 5:00 PM (O3: 28.2/100). Airmine updates local air quality forecasts four times daily.
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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 - 9 August | Pollution peaks at 15:00
AQI:
Poor
60.4/100
PM2.5 (fine particles):
Fair
22.8/100
PM10 (coarse particles):
Good
6.2/100
NO2 (nitrogen dioxide):
Good
17.1/100
O3 (ozone):
Poor
60.4/100
SO2 (sulfur dioxide):
Good
2.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
12.8/100
PM1 (ultrafine particles):
Fair
29.0/100
Levels show the poorest local air quality during the day
Tomorrow - 10 August | Pollution peaks at 17:00
AQI:
Fair
28.2/100
PM2.5 (fine particles):
Good
5.9/100
PM10 (coarse particles):
Good
2.2/100
NO2 (nitrogen dioxide):
Good
2.8/100
O3 (ozone):
Fair
28.2/100
SO2 (sulfur dioxide):
Good
0.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.8/100
PM1 (ultrafine particles):
Good
4.4/100
Pollen forecast in Harrow
View pollen forecastFrequently Asked Questions
Is air quality bad in Harrow right now?
On 9 August 2026, overall air quality in Harrow is poor. AQI is the main air quality indicator at 60.4/100. Pollution peaks around 3:00 PM (O3: 60.4/100).
Will air quality be worse tomorrow in Harrow?
On 10 August 2026, air quality conditions in Harrow will be better than today, with AQI forecast at fair at 28.2/100. Pollution peaks around 5:00 PM (O3: 28.2/100).
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.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
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Data provided by Airmine — Last update: 9 August 2026 at 20:27 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.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
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