Worst air pollution Horsham, today and tomorrow
Today (16 July): Air quality in Horsham is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 2:00 PM (O3: 35.5/100).
Tomorrow (17 July 2026): Air quality in Horsham is medium. AQI improves to medium; O3 decreases to medium; all other pollutants stay as today. Pollution peaks around 4:00 PM (O3: 48.7/100). 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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Emissions along the M8 represent the town's main traffic-related pollution source. Air quality in Horsham is shaped by its location in West Sussex, where vehicle traffic and everyday urban activity dominate local sources. Prevailing westerlies usually ensure decent dispersal, so levels generally stay within the moderate range typical of UK towns.
Today - 16 July | Pollution peaks at 14:00
AQI:
Fair
35.5/100
PM2.5 (fine particles):
Good
8.6/100
PM10 (coarse particles):
Good
3.0/100
NO2 (nitrogen dioxide):
Good
9.4/100
O3 (ozone):
Fair
35.5/100
SO2 (sulfur dioxide):
Good
1.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
4.3/100
PM1 (ultrafine particles):
Good
7.7/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 16:00
AQI:
Medium
48.7/100
PM2.5 (fine particles):
Good
13.7/100
PM10 (coarse particles):
Good
4.4/100
NO2 (nitrogen dioxide):
Good
13.4/100
O3 (ozone):
Medium
48.7/100
SO2 (sulfur dioxide):
Good
2.3/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.7/100
PM1 (ultrafine particles):
Good
13.9/100
Pollen forecast in Horsham
View pollen forecastFrequently Asked Questions
Is air quality bad in Horsham right now?
On 16 July 2026, overall air quality in Horsham is fair. AQI is the main air quality indicator at 35.5/100. Pollution peaks around 2:00 PM (O3: 35.5/100).
Will air quality be worse tomorrow in Horsham?
On 17 July 2026, air quality conditions in Horsham will be better than today, with AQI forecast at medium at 48.7/100. Pollution peaks around 4:00 PM (O3: 48.7/100).
When is air pollution at its worst in Horsham?
Spring and autumn tend to be the calmer, more moderate stretches by comparison. If you're tracking air quality in Horsham, expect it to move around quite a bit through the year. Once the heating goes on and the air turns still, pollution from the M8 and nearby chimneys tends to build up rather than clear. Come summer, it's ozone rather than particulates that's the bigger concern, especially on still, sunny days.
Are air quality levels in Horsham 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