Metro area air quality · 2025

Bloomington, IN

Median AQI 43 (Good). 67.7% of monitored days rated Good across this metro's EPA monitoring network.

43
Median AQI
67.7%
Good-air days
0
Unhealthy days
39%
Cleaner than US metros

Bloomington, IN posted a 2025 median AQI of 43 (Good) with 67.7% Good days

According to the U.S. EPA Air Quality System, the Bloomington, IN CBSA recorded a median AQI of 43 across 365 monitored days in 2025, with 67.7% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.

Data source EPA Air Quality System (AQS)

Cleaner than US metros
The Bloomington, IN CBSA's 67.7% Good-day share places it cleaner than 39% of US metros in 2025.
Closest median-AQI peer
Ashtabula, OH (81.2% Good, median AQI 43) is the closest nationwide median-AQI peer to Bloomington, IN.
2020–2025 Good-day shift
Bloomington, IN's Good-day share moved +2.4 points from 2020 to 2025 (median AQI -1).
Median AQI
Median AQI: 43

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

Bloomington, IN's peak reading 90 stays in the lower max-AQI tercile on this extract. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 43 and 67.7% of 365 monitored days in the Good band.

43
median AQI · Good
67.7%
days rated Good
39%
cleaner than US metros
90
worst single reading

No day crossed into the Unhealthy tier across the metro's monitors in 2025.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Bloomington, IN metro's Good-day share fell from 71.0% to 67.7% between the 2024 and 2025 EPA annual releases, a change of -3.4 percentage points.

Compared against 366 monitored days in 2024 and 365 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

Bloomington, IN's peak reading 90 stays in the lower max-AQI tercile on this extract. Signature read: peak AQI 90 (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 43 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 247 Good (68%), 118 Moderate (32%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 61; the highest single-day reading hit 90 (Moderate).

Across 2020–2025, Good-day share shifted +2.4 points and median AQI moved -1 (stable). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Ashtabula, OH (81.2% good, AQI 43); Champaign-Urbana, IL (65.8% good, AQI 43); Cleveland, MS (71.9% good, AQI 43).

Understanding AQI →

Air Quality Summary

Median AQI

43

Good

Good Days

67.7%

247 of 365 days

Max AQI

90

Moderate

Health Grade

Moderate

90th pct: 61

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

247

68%

Moderate

118

32%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Bloomington, IN metro area's air quality is rated Moderate based on 67.7% good air days. No unhealthy air days were recorded in 2025.

Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.

How does the Bloomington, IN metro compare?

How Bloomington, IN compares

Good-day share worse than typical
Bloomington, IN 67.7%
Ashtabula, OH 81.2%
Typical US metro 70.6%
Median AQI worse than typical
Bloomington, IN 43
Ashtabula, OH 43
Typical US metro 41
Unhealthy days / yr better than typical
Bloomington, IN 0
Ashtabula, OH 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is stable in the Bloomington, IN metro. Highest Good-day share: 2022 (71.9%, 261 of 363 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 239 127 0 44
2021 220 145 0 44
2022 261 102 0 43
2023 213 140 1 47
2024 260 106 0 43
2025 247 118 0 43

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Bloomington, IN (43).

Ashtabula, OH

Median AQI 43 · 81.2% Good-day share

43

Champaign-Urbana, IL

Median AQI 43 · 65.8% Good-day share

43

Cleveland, MS

Median AQI 43 · 71.9% Good-day share

43

Columbus, IN

Median AQI 43 · 72.6% Good-day share

43

Durham-Chapel Hill, NC

Median AQI 43 · 71.5% Good-day share

43

Elizabethtown-Fort Knox, KY

Median AQI 43 · 73.4% Good-day share

43

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Bloomington, IN's 0 (independent of median AQI).

Aberdeen, SD

0 unhealthy-or-worse days · median AQI 27

27

Aberdeen, WA

0 unhealthy-or-worse days · median AQI 22

22

Adrian, MI

0 unhealthy-or-worse days · median AQI 41

41

Akron, OH

0 unhealthy-or-worse days · median AQI 45

45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

27

Frequently Asked Questions

What is the 90th percentile AQI for Bloomington, IN? ▼
The 90th percentile AQI for the Bloomington, IN metro area is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 90 (Moderate).
How many unhealthy air days does Bloomington, IN have? ▼
In 2025, the Bloomington, IN metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 90.
What is the air quality in the Bloomington, IN metro area? ▼
The Bloomington, IN metro area has a median Air Quality Index (AQI) of 43, rated "Good." 67.7% of monitored days (247 out of 365) had good air quality in 2025.
Is air quality in Bloomington, IN getting better or worse? ▼
Air quality in the Bloomington, IN metro is stable across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2022 at 71.9% (261 of 363 days). Lowest qualifying Good-day share: 2023 at 60.2% (213 of 354 days).
What does AQI 43 mean for health? ▼
An AQI of 43 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
How does Bloomington, IN compare to other metro areas? ▼
The Bloomington, IN metro has 67.7% good air days. Similar metros: Ashtabula, OH (81.2% good), Champaign-Urbana, IL (65.8% good), Cleveland, MS (71.9% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Bloomington, IN, 2025. See our methodology for how AQI, median, and coverage figures are computed.

Read our methodology , how this data is sourced, computed, and verified.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, Bloomington, IN · 2020–2025