Castlegar vs Sault Ste. Marie: PM2.5 compared

Over the last year, Castlegar's air was about 1.8× as polluted as Sault Ste. Marie's: PM2.5 averaged 11.5 µg/m³ against 6.5, on the 300 days both cities were measured. Castlegar had the dirtier air on 239 of those days, Sault Ste. Marie on 61. Castlegar was over the WHO's daily guideline of 15 µg/m³ on 39 of them, Sault Ste. Marie on 7.

Right now

Castlegar#770on the 24-hour board of 2,002, at 45 US AQI (8.1 µg/m³)

Sault Ste. Marie#1,855on the 24-hour board of 2,002, at 15 US AQI (2.7 µg/m³)

The last year, day by day

Castlegar

Sault Ste. Marie

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

Monthly means in µg/m³ over the days both cities were measured. Solid: Castlegar. Faded: Sault Ste. Marie. A month shows once both share 10 such days. Dashed line: the WHO daily guideline, 15 µg/m³.

Year by year

Year	Castlegar	Sault Ste. Marie	Days both measured	Days Castlegar was worse
2026 so far	58	42	226	173
2025	42	36	336	225
2024	39	26	336	224
2023	54	43	281	176

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

11 Aug 2026227152.0 µg/m³
9 Aug 2026193116.0 µg/m³
7 Aug 2026187107.0 µg/m³

Sault Ste. Marie

16 Jul 2026467309.0 µg/m³
15 Jul 2026260185.0 µg/m³
18 Jul 202616372.2 µg/m³

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).

Sault Ste. Marie

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

Use this page

SmogRank, PM2.5 daily means compared, Castlegar and Sault Ste. Marie, 7 Oct 2025 – 6 Oct 2026, smogrank.com/compare/ca-castlegar/ca-sault-ste-marie (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.