What is the air quality in Thunder Bay?

Thunder Bay, Canada has an annual US AQI of 33 (Reasonable) and average PM2.5 of 5.3 µg/m³, ranking #95 of 5856 cities. Main pollutant: O3.

What is the cleanest month in Thunder Bay?

October is typically the cleanest month (AQI 26) and April the most polluted (AQI 38).

Where does Thunder Bay's air quality data come from?

PM2.5: 1998–2024 (monitors 2001–2024, satellite 1998–2002, 2005, 2023). Measured by government monitoring stations. Full sources are on the methodology page.

Thunder Bay, Canada — Air Quality & Clean City Guide 2026

Thunder Bay Air Quality Data

Global rank	City	Continent	AQI	PM2.5
95	Thunder Bay, Canada	North America	AQI 33	PM2.5 5.3 µg/m³