Sofia Seasonal Pollution
Sofia usually records its highest OpenAQ-derived EPA AQI in January and its cleanest month in April. The page uses OpenAQ-derived daily history for 7 mapped monitoring locations in Sofia City, Bulgaria.
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Average EPA AQI
51
Rank 15 of 35 cities by average AQI
PM2.5
12.4
ug/m3 annualized city average
Seasonality
January
Cleanest: April
Health indicator
0.6
cigarette-equivalent per day
Yearly EPA AQI trend
Seasonal EPA AQI heatmap
JanFebMarAprMayJunJulAugSepOctNovDec
Sofia
84
66
55
34
38
39
40
41
44
49
54
61
What this seasonality page measures
Find each city's worst and cleanest months from daily OpenAQ-derived EPA AQI.
For Sofia, the current global analytics build covers 367 daily rows from 2023-12-31 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.