Cardiff Seasonal Pollution
Cardiff usually records its highest OpenAQ-derived EPA AQI in February and its cleanest month in December. The page uses OpenAQ-derived daily history for 2 mapped monitoring locations in Wales, United Kingdom.
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Average EPA AQI
36
Rank 84 of 171 cities by average AQI
PM2.5
8.0
ug/m3 annualized city average
Seasonality
February
Cleanest: December
Health indicator
0.4
cigarette-equivalent per day
Yearly EPA AQI trend
Seasonal EPA AQI heatmap
JanFebMarAprMayJunJulAugSepOctNovDec
Cardiff
48
48
47
33
43
36
28
37
43
34
17
10
What this seasonality page measures
Find each city's worst and cleanest months from daily OpenAQ-derived EPA AQI.
For Cardiff, the current global analytics build covers 342 daily rows from 2024-01-01 to 2024-12-31. The calculations normalize PM2.5 and PM10 observations into US EPA AQI bands so country, city, and tool pages use one consistent method.