Worst air pollution Cardiff Bay - Caerdydd, today and tomorrow
Today (9 August): Air quality in Cardiff Bay is poor. AQI and O3 are poor; PM2.5 and PM1 are fair; NO2 is medium; PM10, SO2, CO, and HCHO are good. Pollution peaks around 3:00 PM (O3: 60.4/100).
Tomorrow (10 August 2026): Air quality in Cardiff Bay is fair. AQI improves to fair; PM2.5 decreases to good; NO2 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.
Get the full experience in the Airmine app.
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
Follow your pollen exposure and performance with the free Airmine–Strava integration. See your pollen and air quality exposure for every Strava activity.
The A40 generates consistent traffic-related NO₂ and PM2.5, particularly during peak commuting hours. Air quality in Cardiff Bay is shaped by its location in Cardiff, where vehicle traffic and everyday urban activity dominate local sources. Prevailing westerlies tend to disperse pollutants reasonably well, keeping readings close to typical UK small-town levels.
Today - 9 August | Pollution peaks at 15:00
AQI:
Poor
60.4/100
PM2.5 (fine particles):
Fair
27.6/100
PM10 (coarse particles):
Good
7.7/100
NO2 (nitrogen dioxide):
Medium
50.0/100
O3 (ozone):
Poor
60.4/100
SO2 (sulfur dioxide):
Good
11.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
12.8/100
PM1 (ultrafine particles):
Fair
34.5/100
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
7.3/100
PM10 (coarse particles):
Good
2.7/100
NO2 (nitrogen dioxide):
Good
12.9/100
O3 (ozone):
Fair
28.2/100
SO2 (sulfur dioxide):
Good
2.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.8/100
PM1 (ultrafine particles):
Good
5.4/100
Other Landmarks in Caerdydd
Frequently Asked Questions
Is air quality bad in Cardiff Bay right now?
On 9 August 2026, overall air quality in Cardiff Bay 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 Cardiff Bay?
On 10 August 2026, air quality conditions in Cardiff Bay 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 Cardiff Bay?
Ask a local in Cardiff Bay and they'll tell you air quality changes noticeably from season to season. Summer sunshine can drive up ozone locally, though overall air generally moves and clears more freely than in winter. The coldest months usually bring the worst readings, as heating and temperature inversions keep A40 emissions from dispersing normally. Spring and autumn tend to be the calmer, more moderate stretches by comparison.
Are air quality levels in Cardiff Bay 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.
Want to see air quality forecasts for other cities in United Kingdom?
Check air quality in other popular cities:
Data provided by Airmine — Last update: 10 August 2026 at 02:34 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.
Get the full experience in the Airmine app.