SmogRank / Castlegar / Saint-Jean-sur-Richelieu

Castlegar vs Saint-Jean-sur-Richelieu: PM2.5 compared

Over the last year, Castlegar's air was about 2.2× as polluted as Saint-Jean-sur-Richelieu's: PM2.5 averaged 11.1 µg/m³ against 5.0, on the 317 days both cities were measured. Castlegar had the dirtier air on 229 of those days, Saint-Jean-sur-Richelieu on 85. Castlegar was over the WHO's daily guideline of 15 µg/m³ on 39 of them, Saint-Jean-sur-Richelieu on 2.

Right now

Castlegar#770on the 24-hour board of 2,002, at 45 US AQI (8.1 µg/m³)
Saint-Jean-sur-Richelieu#1,789on the 24-hour board of 2,002, at 17 US AQI (3.1 µg/m³)

The last year, day by day

Castlegar
Saint-Jean-sur-Richelieu
Each city's daily mean from 7 Oct 2025 to 6 Oct 2026, one stripe a day, coloured by band. A blank stripe is a day without a daily mean.

Month by month

Castlegar, Nov 2025: 9.2 µg/m³Saint-Jean-sur-Richelieu, Nov 2025: 3.4 µg/m³Nov2025Castlegar, Dec 2025: 6.3 µg/m³Saint-Jean-sur-Richelieu, Dec 2025: 4.4 µg/m³DecCastlegar, Jan 2026: 8.4 µg/m³Saint-Jean-sur-Richelieu, Jan 2026: 7.7 µg/m³Jan2026Castlegar, Feb 2026: 6.1 µg/m³Saint-Jean-sur-Richelieu, Feb 2026: 5.6 µg/m³FebCastlegar, Mar 2026: 6.2 µg/m³Saint-Jean-sur-Richelieu, Mar 2026: 4.2 µg/m³MarCastlegar, Apr 2026: 6.2 µg/m³Saint-Jean-sur-Richelieu, Apr 2026: 4.0 µg/m³AprCastlegar, May 2026: 5.9 µg/m³Saint-Jean-sur-Richelieu, May 2026: 3.5 µg/m³MayCastlegar, Jun 2026: 4.5 µg/m³Saint-Jean-sur-Richelieu, Jun 2026: 5.0 µg/m³JunCastlegar, Jul 2026: 19.7 µg/m³Saint-Jean-sur-Richelieu, Jul 2026: 8.4 µg/m³JulCastlegar, Aug 2026: 39.3 µg/m³Saint-Jean-sur-Richelieu, Aug 2026: 5.6 µg/m³AugCastlegar, Sep 2026: 8.0 µg/m³Saint-Jean-sur-Richelieu, Sep 2026: 5.2 µg/m³SepOct
Monthly means in µg/m³ over the days both cities were measured. Solid: Castlegar. Faded: Saint-Jean-sur-Richelieu. A month shows once both share 10 such days. Dashed line: the WHO daily guideline, 15 µg/m³.

Year by year

YearCastlegarSaint-Jean-sur-RichelieuDays both measuredDays Castlegar was worse
2026 so far5730240164
20254231339234
20243928359230
20235544255141

Means in US AQI over the days both cities were measured that year; a year shows once they share 30 such days.

Each city's worst days

Castlegar

Saint-Jean-sur-Richelieu

Daily means in US AQI, with µg/m³ beside them, since the index stops at its top value, over the days both cities were measured in the last year. Each date opens that day's world board.

Compare either city with another

Castlegar

Side by side with Creston (the nearest), Edmonton (Canada's 2nd worst on 30 days), Gujranwala (the world's worst on 30 days).

Saint-Jean-sur-Richelieu

Side by side with Brossard (the nearest), Gujranwala (the world's worst on 30 days).

Use this page

SmogRank, PM2.5 daily means compared, Castlegar and Saint-Jean-sur-Richelieu, 7 Oct 2025 – 6 Oct 2026, smogrank.com/compare/ca-castlegar/ca-saint-jean-sur-richelieu (accessed 7 Oct 2026).

You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.

The same rules as every SmogRank figure: reference monitors first, and a day counts with 18 measured hours. How we measure.

Updated 2026-10-07 08:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.