Worst air pollution Hirwaun, today and tomorrow
Today (20 September): Air quality in Hirwaun is fair. AQI, PM2.5, PM10, NO2, and PM1 are fair; O3, SO2, CO, and HCHO are good. Pollution peaks around 9:00 PM (NO2: 39.7/100).
Tomorrow (21 September 2026): Air quality in Hirwaun is moderate. AQI worsens to moderate; PM2.5 increases to moderate; PM10 increases to moderate; NO2 increases to moderate; PM1 increases to moderate; all other pollutants stay as today. Pollution peaks around 8:00 PM (NO2: 57.7/100). Airmine updates local air quality forecasts four times daily.
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Air quality in Hirwaun is shaped by its location in Rhondda Cynon Taf, where vehicle traffic and everyday urban activity dominate local sources. The prevailing Atlantic airflow offer a degree of natural ventilation, keeping pollution broadly in line with comparable UK towns. Rush-hour queues near the A470 are usually when readings climb the most.
Today - 20 September | Pollution peaks at 21:00
AQI:
Fair
39.7/100
PM2.5 (fine particles):
Fair
38.4/100
PM10 (coarse particles):
Fair
24.8/100
NO2 (nitrogen dioxide):
Fair
39.7/100
O3 (ozone):
Good
16.0/100
SO2 (sulfur dioxide):
Good
5.6/100
CO (carbon monoxide):
Good
0.9/100
HCHO (formaldehyde):
Good
8.3/100
PM1 (ultrafine particles):
Fair
25.7/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 20:00
AQI:
Moderate
57.7/100
PM2.5 (fine particles):
Moderate
50.1/100
PM10 (coarse particles):
Moderate
42.3/100
NO2 (nitrogen dioxide):
Moderate
57.7/100
O3 (ozone):
Good
18.2/100
SO2 (sulfur dioxide):
Good
13.3/100
CO (carbon monoxide):
Good
1.6/100
HCHO (formaldehyde):
Good
19.8/100
PM1 (ultrafine particles):
Moderate
45.1/100
Pollen forecast in Hirwaun
View pollen forecastFrequently Asked Questions
Is air quality bad in Hirwaun right now?
On 20 September 2026, overall air quality in Hirwaun is fair. AQI is the main air quality indicator at 39.7/100. Pollution peaks around 9:00 PM (NO2: 39.7/100).
Will air quality be worse tomorrow in Hirwaun?
On 21 September 2026, air quality conditions in Hirwaun will be worse than today, with AQI forecast at moderate at 57.7/100. Pollution peaks around 8:00 PM (NO2: 57.7/100).
When is air pollution at its worst in Hirwaun?
For much of spring and autumn, things settle into a fairly unremarkable middle ground. If you're tracking air quality in Hirwaun, expect it to move around quite a bit through the year. Through the colder months, readings near the A470 often rise, since chimney smoke and stagnant air stop pollutants clearing away. 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.
Are air quality levels in Hirwaun 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: 20 September 2026 at 14:33 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.
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.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
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