Herstal Seasonal Pollution
Herstal usually records its highest OpenAQ-derived EPA AQI in November and its cleanest month in April. The page uses OpenAQ-derived daily history for 1 mapped monitoring location in Wallonia, Belgium.
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Average EPA AQI
32
Rank 53 of 67 cities by average AQI
PM2.5
6.7
ug/m3 annualized city average
Seasonality
November
Cleanest: April
Health indicator
0.3
cigarette-equivalent per day
Yearly EPA AQI trend
Seasonal EPA AQI heatmap
JanFebMarAprMayJunJulAugSepOctNovDec
Herstal
42
25
32
16
35
36
21
34
33
32
43
28
What this seasonality page measures
Find each city's worst and cleanest months from daily OpenAQ-derived EPA AQI.
For Herstal, the current global analytics build covers 328 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.