Metro area air quality · 2024
Bloomington, IL
Median AQI 44 (Good). 69.4% of monitored days rated Good across this metro's EPA monitoring network.
- 44
- Median AQI
- 69.4%
- Good-air days
- 0
- Unhealthy days
- 43%
- Cleaner than US metros
Aggregated from EPA Air Quality System (2024), 366 monitored days. EPA AQS →
The verdict
The Bloomington, IL metro runs good on the EPA scale — a median AQI of 44 with 69.4% of 366 monitored days in the Good band.
- 44
- median AQI · Good
- 69.4%
- days rated Good
- 43%
- cleaner than US metros
- 112
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2024.
Insights: Bloomington, IL metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 44 over 366 measured days in 2024, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 254 Good days (69%), 111 Moderate (30%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 61 while the highest single-day reading hit 112 (USG). Metro residents averaged roughly 20.8 clean-air days per 30-day window across the reporting year.
Across the 2020–2024 trend window, good days shifted by +47 and the median AQI moved -4 points, which classifies the multi-year trajectory as improving. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Amarillo, TX (72.8% good, AQI 44); Berlin, NH-VT (81.1% good, AQI 44); Buffalo-Cheektowaga-Niagara Falls, NY (63.7% good, AQI 44).
Air Quality Summary
Median AQI
44
Good
Good Days
69.4%
254 of 366 days
Max AQI
112
USG
Health Grade
Moderate
90th pct: 61
AQI Day Breakdown (2024)
Distribution of 366 monitored days across EPA AQI categories.
Good
254
69%
Moderate
111
30%
USG
1
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Bloomington, IL metro area's air quality is rated Moderate based on 69.4% good air days. No unhealthy air days were recorded in 2024.
Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.
How does the Bloomington, IL metro compare?
How Bloomington, IL compares
5-Year Air Quality Trend
Air quality is improving in the Bloomington, IL metro. Best year: 2024 (254 good days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 207 | 154 | 0 | 48 | 136 |
| 2021 | 191 | 173 | 0 | 48 | 107 |
| 2022 | 207 | 156 | 0 | 47 | 129 |
| 2023 | 184 | 168 | 2 | 50 | 289 |
| 2024 | 254 | 111 | 0 | 44 | 112 |
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Frequently Asked Questions
What is the air quality in the Bloomington, IL metro area? ▼
How many unhealthy air days does Bloomington, IL have? ▼
Is air quality in Bloomington, IL getting better or worse? ▼
What does AQI 44 mean for health? ▼
What is the 90th percentile AQI for Bloomington, IL? ▼
How does Bloomington, IL compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2024. The AQS collects ambient air monitoring data from state, local, and tribal monitoring agencies across the United States.
Metrics: Air Quality Index (AQI) is calculated using EPA-standard breakpoints for six criteria pollutants: PM2.5, PM10, Ozone, NO2, CO, and SO2. Median AQI, max AQI, and 90th percentile AQI are computed from daily measurements. Good days percentage reflects days with AQI 0–50.
Coverage: 501 metro areas (Core Based Statistical Areas). Only metros with active monitoring stations are included. Unmonitored areas are not represented.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary files (metro-level) · 2020–2024