SmogRank / United States / Illinois / Brookfield
Brookfield, month by month
Brookfield has a measured daily mean on 999 days since 3 January 2024. Its worst month was July 2026, at 79 US AQI (24.2 µg/m³), 231st of 2,784 cities on that month's world ranking. Its cleanest was May 2025, at 27 US AQI (4.8 µg/m³). 2025 averaged 51 US AQI (9.3 µg/m³), against 47 US AQI (8.5 µg/m³) in 2024.
Every month since 2024
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
Brookfield's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2026 | 7924.2 µg/m³ | 231stof 2,784 | Northern United States and Canada, July 2026 |
| July 2025 | 6114.5 µg/m³ | 444thof 2,889 | North-eastern United States and Canada, 29 July to 9 August 2025 Northern United States, July 2025and 1 more |
| August 2025 | 5813.1 µg/m³ | 561stof 2,901 | North-eastern United States and Canada, 29 July to 9 August 2025 |
| June 2025 | 5812.9 µg/m³ | 675thof 2,508 | Northern United States and Canada, June 2025 Northern United States and Canada, May and June 2025 |
| February 2026 | 5812.7 µg/m³ | 955thof 2,866 | North-eastern United States and Canada, 14 to 19 February 2026 |
| March 2026 | 5712.2 µg/m³ | 1,175thof 2,971 | North-eastern United States and Canada, March 2026 |
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.
Brookfield's worst days
Daily means, the highest since 3 Jan 2024; 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, Brookfield, United States, 3 Jan 2024 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/brookfield-illinois/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.
Brookfield 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).