Worst air pollution Mountain Ash, today and tomorrow
Today (16 July): Air quality in Mountain Ash 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 Mountain Ash 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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Mountain Ash's air quality reflects its position within Rhondda Cynon Taf, with local traffic and the town's built-up core as the main contributors. Residential heating and light industry add a modest seasonal contribution, though southwesterly winds keep overall levels moderate. The A40 generates consistent traffic-related NO₂ and PM2.5, particularly during peak commuting hours.
Today - 16 July | Pollution peaks at 15:00
AQI:
Fair
34.0/100
PM2.5 (fine particles):
Good
9.1/100
PM10 (coarse particles):
Good
3.1/100
NO2 (nitrogen dioxide):
Good
12.1/100
O3 (ozone):
Fair
34.0/100
SO2 (sulfur dioxide):
Good
1.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.8/100
PM1 (ultrafine particles):
Good
8.7/100
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
12.4/100
PM10 (coarse particles):
Good
4.2/100
NO2 (nitrogen dioxide):
Good
17.1/100
O3 (ozone):
Medium
43.6/100
SO2 (sulfur dioxide):
Good
2.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.2/100
PM1 (ultrafine particles):
Good
11.6/100
Pollen forecast in Mountain Ash
View pollen forecastFrequently Asked Questions
Is air quality bad in Mountain Ash right now?
On 16 July 2026, overall air quality in Mountain Ash 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 Mountain Ash?
On 17 July 2026, air quality conditions in Mountain Ash 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 Mountain Ash?
If you're tracking air quality in Mountain Ash, expect it to move around quite a bit through the year. In summer, ozone can build up on sunny afternoons, though windier, warmer weather usually helps clear traffic-related pollution faster than in winter. Through the colder months, readings near the A40 often rise, since chimney smoke and stagnant air stop pollutants clearing away. The shoulder seasons generally bring the mildest readings of the year.
Are air quality levels in Mountain Ash 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