What is the air quality in St. Catharines?

St. Catharines, Canada has an annual US AQI of 42 (Reasonable) and average PM2.5 of 7.6 µg/m³, ranking #324 of 5856 cities. Main pollutant: PM2.5.

What is the cleanest month in St. Catharines?

October is typically the cleanest month (AQI 34) and July the most polluted (AQI 52).

Where does St. Catharines's air quality data come from?

PM2.5: 1998–2026 (monitors 1998–2013, 2015–2026, satellite 1998, 2002, 2014; 2025–2026 provisional). Measured by government monitoring stations. Full sources are on the methodology page.

St. Catharines, Canada — Air Quality & Clean City Guide 2026

St. Catharines Air Quality Data

Global rank	City	Continent	AQI	PM2.5
324	St. Catharines, Canada	North America	AQI 42	PM2.5 7.6 µg/m³