SmogRank / Castlegar / Fort St. John

Castlegar vs Fort St. John: PM2.5 compared

Over the last year, Castlegar's air was about 2.0× as polluted as Fort St. John's: PM2.5 averaged 10.8 µg/m³ against 5.5, on the 310 days both cities were measured. Castlegar had the dirtier air on 225 of those days, Fort St. John on 81. Castlegar was over the WHO's daily guideline of 15 µg/m³ on 34 of them, Fort St. John on 7.

Right now

Castlegar#770on the 24-hour board of 2,002, at 45 US AQI (8.1 µg/m³)
Fort St. John#1,920on the 24-hour board of 2,002, at 12 US AQI (2.2 µg/m³)

The last year, day by day

Castlegar
Fort St. John
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: 9.1 µg/m³Fort St. John, Nov 2025: 5.4 µg/m³Nov2025Castlegar, Dec 2025: 6.3 µg/m³Fort St. John, Dec 2025: 4.0 µg/m³DecCastlegar, Jan 2026: 8.4 µg/m³Fort St. John, Jan 2026: 5.0 µg/m³Jan2026Castlegar, Feb 2026: 6.1 µg/m³Fort St. John, Feb 2026: 3.6 µg/m³FebCastlegar, Mar 2026: 6.4 µg/m³Fort St. John, Mar 2026: 4.6 µg/m³MarCastlegar, Apr 2026: 6.5 µg/m³Fort St. John, Apr 2026: 4.9 µg/m³AprCastlegar, May 2026: 5.9 µg/m³Fort St. John, May 2026: 4.8 µg/m³MayCastlegar, Jun 2026: 4.4 µg/m³Fort St. John, Jun 2026: 4.7 µg/m³JunCastlegar, Jul 2026: 18.2 µg/m³Fort St. John, Jul 2026: 11.6 µg/m³JulCastlegar, Aug 2026: 43.8 µg/m³Fort St. John, Aug 2026: 8.2 µg/m³AugCastlegar, Sep 2026: 8.1 µg/m³Fort St. John, Sep 2026: 4.9 µg/m³SepOct
Monthly means in µg/m³ over the days both cities were measured. Solid: Castlegar. Faded: Fort St. John. A month shows once both share 10 such days. Dashed line: the WHO daily guideline, 15 µg/m³.

Year by year

YearCastlegarFort St. JohnDays both measuredDays Castlegar was worse
2026 so far5633232164
20254239337221
20243641325193
20235472276120

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

Fort St. John

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).

Fort St. John

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

Use this page

SmogRank, PM2.5 daily means compared, Castlegar and Fort St. John, 7 Oct 2025 – 6 Oct 2026, smogrank.com/compare/ca-castlegar/ca-fort-st-john (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.