SmogRank / Canada / British Columbia / Delta
Delta, month by month
Delta has a measured daily mean on 1,290 days since 1 January 2023. Its worst month was August 2023, at 34 US AQI (6.2 µg/m³), 1,581st of 1,980 cities on that month's world ranking. Its cleanest was May 2024, at 13 US AQI (2.4 µg/m³). 2025 averaged 23 US AQI (4.1 µg/m³), against 19 US AQI (3.5 µg/m³) in 2024.
Every month since 2023
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Months without a mean, and why
2 months
| Month | Why |
|---|---|
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 1 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive, 2 with under 18 hours of readings or readings that failed our checks. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Delta's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| August 2023 | 346.2 µg/m³ | 1,581stof 1,980 | North-western United States and Canada, August 2023 |
| September 2025 | 325.7 µg/m³ | 2,242ndof 3,104 | – |
| August 2025 | 305.4 µg/m³ | 2,635thof 2,901 | – |
| August 2026 | 305.4 µg/m³ | 2,658thof 2,896 | – |
| September 2026 | 295.3 µg/m³ | 2,171stof 2,981 | – |
| November 2023 | 295.2 µg/m³ | 1,931stof 2,243 | – |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Delta's worst days
| Day | US AQI | Episode |
|---|---|---|
| 26 Aug 2023 | 8527.3 µg/m³ | North-western United States and Canada, August 2023 |
| 27 Aug 2023 | 8125.2 µg/m³ | North-western United States and Canada, August 2023 |
| 22 Jul 2026 | 7320.7 µg/m³ | – |
| 25 Aug 2023 | 6918.6 µg/m³ | North-western United States and Canada, August 2023 |
| 21 Jul 2026 | 6416.2 µg/m³ | – |
| 28 Aug 2023 | 5913.5 µg/m³ | North-western United States and Canada, August 2023 |
| 31 Oct 2023 | 5913.4 µg/m³ | – |
| 1 Nov 2023 | 5813.0 µg/m³ | – |
| 25 Aug 2026 | 5813.0 µg/m³ | – |
| 6 Aug 2026 | 5812.7 µg/m³ | – |
Daily means, the highest since 1 Jan 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Delta, Canada, 1 Jan 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/ca/delta/history (accessed 12 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.
Delta now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 17:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).