Haarlem Seasonal Pollution
Haarlem usually records its highest OpenAQ-derived EPA AQI in May and its cleanest month in February. The page uses OpenAQ-derived daily history for 2 mapped monitoring locations in Noord-Holland, Netherlands.
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Average EPA AQI
34
Rank 46 of 71 cities by average AQI
PM2.5
8.4
ug/m3 annualized city average
Seasonality
May
Cleanest: February
Health indicator
0.4
cigarette-equivalent per day
Yearly EPA AQI trend
Seasonal EPA AQI heatmap
JanFebMarAprMayJunJulAugSepOctNovDec
Haarlem
18
16
37
25
48
39
31
31
33
35
44
47
What this seasonality page measures
Find each city's worst and cleanest months from daily OpenAQ-derived EPA AQI.
For Haarlem, the current global analytics build covers 360 daily rows from 2024-01-03 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.