Castlegar vs Greater Sudbury: PM2.5 compared

Over the last year, Castlegar's air was about 1.8× as polluted as Greater Sudbury's: PM2.5 averaged 9.5 µg/m³ against 5.2, on the 304 days both cities were measured. Castlegar had the dirtier air on 224 of those days, Greater Sudbury on 78. Castlegar was over the WHO's daily guideline of 15 µg/m³ on 32 of them, Greater Sudbury on 8.

Right now

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

Greater Sudbury#1,816on the 24-hour board of 2,002, at 17 US AQI (3.0 µg/m³)

The last year, day by day

Castlegar

Greater Sudbury

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: Greater Sudbury. A month shows once both share 10 such days. Dashed line: the WHO daily guideline, 15 µg/m³.

Year by year

Year	Castlegar	Greater Sudbury	Days both measured	Days Castlegar was worse
2026 so far	53	33	230	163
2025	42	36	341	214
2024	40	29	349	212
2023	54	54	286	160

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
12 Aug 202616271.3 µg/m³
23 Jul 202615358.1 µg/m³

Greater Sudbury

15 Jul 2026198122.0 µg/m³
18 Jul 202613248.2 µg/m³
16 Jul 202612243.9 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).

Greater Sudbury

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

Use this page

SmogRank, PM2.5 daily means compared, Castlegar and Greater Sudbury, 7 Oct 2025 – 6 Oct 2026, smogrank.com/compare/ca-castlegar/ca-greater-sudbury (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.