Worst air pollution Hemel Hempstead, today and tomorrow
Today (16 July): Air quality in Hemel Hempstead 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 Hemel Hempstead 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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Air quality in Hemel Hempstead is shaped by its location in Hertfordshire, where vehicle traffic and everyday urban activity dominate local sources. Emissions along the A82 represent the town's main traffic-related pollution source. Inland breezes from the surrounding countryside 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
8.3/100
PM10 (coarse particles):
Good
2.8/100
NO2 (nitrogen dioxide):
Good
6.8/100
O3 (ozone):
Fair
34.0/100
SO2 (sulfur dioxide):
Good
0.9/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.8/100
PM1 (ultrafine particles):
Good
7.9/100
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
11.3/100
PM10 (coarse particles):
Good
3.8/100
NO2 (nitrogen dioxide):
Good
9.6/100
O3 (ozone):
Medium
43.6/100
SO2 (sulfur dioxide):
Good
1.3/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.2/100
PM1 (ultrafine particles):
Good
10.6/100
Pollen forecast in Hemel Hempstead
View pollen forecastFrequently Asked Questions
Is air quality bad in Hemel Hempstead right now?
On 16 July 2026, overall air quality in Hemel Hempstead 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 Hemel Hempstead?
On 17 July 2026, air quality conditions in Hemel Hempstead 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 Hemel Hempstead?
Seasons make a real difference to air quality in Hemel Hempstead, more than most people realise. The coldest months usually bring the worst readings, as heating and temperature inversions keep A82 emissions from dispersing normally. Warmer months swap one problem for another — less smoke and heating pollution, but more ozone on the sunniest days. Spring and autumn are typically the easiest months, air-quality-wise, for most residents.
Are air quality levels in Hemel Hempstead 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