SmogRank / United States / Minnesota / Duluth
Duluth, month by month
Duluth has a measured daily mean on 1,295 days since 11 January 2023. Its worst month was July 2026, at 118 US AQI (42.3 µg/m³), 59th of 2,784 cities on that month's world ranking. Its cleanest was April 2024, at 17 US AQI (3.0 µg/m³). 2025 averaged 51 US AQI (9.1 µg/m³), against 32 US AQI (5.8 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
3 months
| Month | Why |
|---|---|
| Apr 2023 | 3 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 14 of 31 days measured; a month needs 22. The others: 6 missing from OpenAQ's archive, 11 with under 18 hours of readings or readings that failed our checks. |
| Jan 2023 | 7 of 31 days measured; a month needs 22. The others: 14 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.
Duluth's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2026 | 11842.3 µg/m³ | 59thof 2,784 | Northern United States and Canada, July 2026 |
| July 2025 | 8426.6 µg/m³ | 115thof 2,889 | North-eastern United States and Canada, 29 July to 9 August 2025 North-eastern United States and Canada, 24 to 28 July 2025and 2 more |
| June 2023 | 7220.2 µg/m³ | 265thof 1,603 | Eastern United States and Canada, June and July 2023 United States and Canada, June 2023and 1 more |
| August 2025 | 6416.1 µg/m³ | 304thof 2,901 | Northern United States and Canada, August 2025 North-eastern United States and Canada, 29 July to 9 August 2025 |
| June 2025 | 6315.7 µg/m³ | 386thof 2,508 | Northern United States and Canada, June 2025 Northern United States and Canada, May and June 2025 |
| July 2023 | 5812.8 µg/m³ | 306thof 1,432 | Northern United States and Canada, July 2023 United States and Canada, July 2023and 1 more |
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.
Duluth's worst days
| Day | US AQI | Episode |
|---|---|---|
| 16 Jul 2026 | 500+466.0 µg/m³ | Northern United States and Canada, July 2026 |
| 15 Jul 2026 | 404277.0 µg/m³ | Northern United States and Canada, July 2026 |
| 17 Jul 2026 | 291216.0 µg/m³ | Northern United States and Canada, July 2026 |
| 12 Jul 2025 | 191112.0 µg/m³ | Northern United States and Canada, July 2025 |
| 3 Jun 2025 | 17996.0 µg/m³ | Northern United States and Canada, May and June 2025 |
| 30 Jul 2025 | 17691.1 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
| 31 Jul 2025 | 17285.4 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
| 1 Aug 2025 | 16981.7 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
| 14 Jun 2023 | 15662.2 µg/m³ | United States and Canada, June 2023 |
| 25 Jul 2025 | 15459.7 µg/m³ | North-eastern United States and Canada, 24 to 28 July 2025 |
Daily means, the highest since 11 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, Duluth, United States, 11 Jan 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/duluth/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.
Duluth now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 18:07 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).