St. Catharines Seasonal Pollution
St. Catharines usually records its highest OpenAQ-derived EPA AQI in February and its cleanest month in March. The page uses OpenAQ-derived daily history for 1 mapped monitoring location in Ontario, Canada.
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Average EPA AQI
33
Rank 59 of 158 cities by average AQI
PM2.5
6.3
ug/m3 annualized city average
Seasonality
February
Cleanest: March
Health indicator
0.3
cigarette-equivalent per day
Yearly EPA AQI trend
Seasonal EPA AQI heatmap
JanFebMarAprMayJunJulAugSepOctNovDec
St. Catharines
38
41
25
26
33
36
39
39
35
28
25
32
What this seasonality page measures
Find each city's worst and cleanest months from daily OpenAQ-derived EPA AQI.
For St. Catharines, the current global analytics build covers 364 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.