SmogRank / United States / Illinois / Granite City
Granite City, month by month
Granite City has a measured daily mean on 1,262 days since 4 January 2023. Its worst month was June 2023, at 67 US AQI (17.7 µg/m³), 313th of 1,603 cities on that month's world ranking. Its cleanest was May 2025, at 35 US AQI (6.3 µg/m³). 2025 averaged 50 US AQI (9.0 µg/m³), against 49 US AQI (8.8 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
4 months
| Month | Why |
|---|---|
| Sep 2024 | 13 of 30 days measured; a month needs 21. The others: 17 with under 18 hours of readings or readings that failed our checks. |
| Apr 2023 | 16 of 30 days measured; a month needs 21. The others: 3 missing from OpenAQ's archive, 11 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 9 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive, 2 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | 2 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive, 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.
Granite City's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| June 2023 | 6717.7 µg/m³ | 313thof 1,603 | Eastern United States and Canada, June and July 2023 United States and Canada, June 2023 |
| July 2026 | 5812.9 µg/m³ | 739thof 2,784 | Northern United States and Canada, July 2026 North-eastern United States, June and July 2026 |
| January 2023 | 5712.5 µg/m³ | 326thof 1,261 | – |
| July 2023 | 5712.3 µg/m³ | 365thof 1,432 | United States and Canada, July 2023 Eastern United States and Canada, June and July 2023 |
| February 2024 | 5712.3 µg/m³ | 451stof 2,486 | – |
| August 2026 | 5611.9 µg/m³ | 579thof 2,896 | – |
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.
Granite City's worst days
| Day | US AQI | Episode |
|---|---|---|
| 28 Jun 2023 | 15865.1 µg/m³ | Eastern United States and Canada, June and July 2023 |
| 15 Mar 2025 | 15864.8 µg/m³ | Eastern United States, March 2025 |
| 1 Aug 2025 | 13147.6 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
| 20 Jul 2026 | 11842.3 µg/m³ | Northern United States and Canada, July 2026 |
| 16 Jul 2023 | 8929.6 µg/m³ | United States and Canada, July 2023 |
| 7 Jun 2025 | 8728.3 µg/m³ | Northern United States and Canada, May and June 2025 |
| 11 Jun 2025 | 8527.2 µg/m³ | Northern United States and Canada, June 2025 |
| 30 Jun 2026 | 8527.2 µg/m³ | North-eastern United States, June and July 2026 |
| 21 Feb 2024 | 8326.2 µg/m³ | – |
| 20 Feb 2024 | 8326.1 µg/m³ | – |
Daily means, the highest since 4 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, Granite City, United States, 4 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/granite-city/history (accessed 13 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.
Granite City now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 01:07 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).