SmogRank / United States / Michigan / Ann Arbor
Ann Arbor, month by month
Ann Arbor has a measured daily mean on 272 days since 23 July 2025. Its worst month was February 2026, at 63 US AQI (15.7 µg/m³), 740th of 2,866 cities on that month's world ranking. Its cleanest was September 2026, at 41 US AQI (7.4 µg/m³).
Every month since 2025
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
7 months
| Month | Why |
|---|---|
| Aug 2026 | 11 of 31 days measured; a month needs 22. The others: 20 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 7 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks. |
| Jun 2026 | 4 of 30 days measured; a month needs 21. The others: 26 with under 18 hours of readings or readings that failed our checks. |
| May 2026 | 8 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks. |
| Apr 2026 | 2 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Oct 2025 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Jul 2025 | 8 of 31 days measured; a month needs 22. The others: 1 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.
Ann Arbor's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| February 2026 | 6315.7 µg/m³ | 740thof 2,866 | North-eastern United States and Canada, 14 to 19 February 2026 North-eastern United States and Canada, 9 to 10 February 2026and 1 more |
| August 2025 | 5812.8 µg/m³ | 606thof 2,901 | North-eastern United States and Canada, 29 July to 9 August 2025 |
| December 2025 | 5611.6 µg/m³ | 1,026thof 3,006 | – |
| March 2026 | 5310.4 µg/m³ | 1,566thof 2,971 | – |
| September 2025 | 529.4 µg/m³ | 805thof 3,104 | – |
| November 2025 | 488.6 µg/m³ | 1,364thof 2,715 | – |
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.
Ann Arbor's worst days
Daily means, the highest since 23 Jul 2025; 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, Ann Arbor, United States, 23 Jul 2025 – 11 Oct 2026. Monitor data from Clarity and AirGradient via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/us/ann-arbor/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.
Ann Arbor now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 22:07 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).