St. Catharines Health Impact
St. Catharines averaged 6.3 ug/m3 PM2.5, equal to 1.3x the WHO annual PM2.5 guideline and about 0.3 cigarettes per day by the simple AQI Now indicator. 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 health page measures
Translate PM2.5 exposure into WHO exceedance and a simple cigarette-equivalent indicator.
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.