Metro area air quality · 2025

Springfield, IL

Median AQI 41 (Good). 70.1% of monitored days rated Good across this metro's EPA monitoring network.

41
Median AQI
70.1%
Good-air days
0
Unhealthy days
46%
Cleaner than US metros

Springfield, IL posted a 2025 median AQI of 41 (Good) with 70.1% Good days

According to the U.S. EPA Air Quality System, the Springfield, IL CBSA recorded a median AQI of 41 across 365 monitored days in 2025, with 70.1% 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 Springfield, IL CBSA's 70.1% Good-day share places it cleaner than 46% of US metros in 2025.
Closest median-AQI peer
Adrian, MI (69.3% Good, median AQI 41) is the closest nationwide median-AQI peer to Springfield, IL.
2020–2025 Good-day shift
Springfield, IL's Good-day share moved +0.9 points from 2020 to 2025 (median AQI -3).
Median AQI
Median AQI: 41

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

The verdict

Springfield, IL's peak reading 142 is in the upper max-AQI tercile among CBSA metros here. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 41 and 70.1% of 365 monitored days in the Good band.

41
median AQI · Good
70.1%
days rated Good
46%
cleaner than US metros
142
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
  • Springfield, IL metro's peak single-day AQI rose from 105 to 142 between the 2024 and 2025 EPA annual releases, a change of +37 points.
  • Springfield, IL metro's Good-day share fell from 72.1% to 70.7% between the 2024 and 2025 EPA annual releases, a change of -1.3 percentage points.

Compared against 365 monitored days in 2024 and 362 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

Springfield, IL's peak reading 142 is in the upper max-AQI tercile among CBSA metros here. Signature read: peak AQI 142 (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 41 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 256 Good (70%), 106 Moderate (29%), and 3 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 61; the highest single-day reading hit 142 (USG).

Across 2020–2025, Good-day share shifted +0.9 points and median AQI moved -3 (stable). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Adrian, MI (69.3% good, AQI 41); Albany-Schenectady-Troy, NY (67.7% good, AQI 41); Ann Arbor, MI (69.3% good, AQI 41).

Health effects of air pollution →

Air Quality Summary

Median AQI

41

Good

Good Days

70.1%

256 of 365 days

Max AQI

142

USG

Health Grade

Moderate

90th pct: 61

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

256

70%

Moderate

106

29%

USG

3

1%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Springfield, IL metro area's air quality is rated Moderate based on 70.1% 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 Springfield, IL metro compare?

How Springfield, IL compares

Good-day share about typical
Springfield, IL 70.1%
Adrian, MI 69.3%
Typical US metro 70.6%
Median AQI about typical
Springfield, IL 41
Adrian, MI 41
Typical US metro 41
Unhealthy days / yr better than typical
Springfield, IL 0
Adrian, MI 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is stable in the Springfield, IL metro. Highest Good-day share: 2024 (72.1%, 263 of 365 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 254 110 0 44
2021 233 129 0 43
2022 220 138 0 45
2023 182 163 2 51
2024 263 102 0 41
2025 256 106 0 41

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Springfield, IL (41).

Adrian, MI

Median AQI 41 · 69.3% Good-day share

41

Albany-Schenectady-Troy, NY

Median AQI 41 · 67.7% Good-day share

41

Ann Arbor, MI

Median AQI 41 · 69.3% Good-day share

41

Bowling Green, KY

Median AQI 41 · 75.6% Good-day share

41

Brunswick, GA

Median AQI 41 · 74.3% Good-day share

41

Decatur, AL

Median AQI 41 · 78.4% Good-day share

41

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Springfield, IL'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

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

Alexandria, LA

0 unhealthy-or-worse days · median AQI 37

37

Frequently Asked Questions

What is the 90th percentile AQI for Springfield, IL? ▼
The 90th percentile AQI for the Springfield, IL metro area is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 142 (USG).
How many unhealthy air days does Springfield, IL have? ▼
In 2025, the Springfield, IL metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 142.
What is the air quality in the Springfield, IL metro area? ▼
The Springfield, IL metro area has a median Air Quality Index (AQI) of 41, rated "Good." 70.1% of monitored days (256 out of 365) had good air quality in 2025.
Is air quality in Springfield, IL getting better or worse? ▼
Air quality in the Springfield, IL 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: 2024 at 72.1% (263 of 365 days). Lowest qualifying Good-day share: 2023 at 52.4% (182 of 347 days).
What does AQI 41 mean for health? ▼
An AQI of 41 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 Springfield, IL compare to other metro areas? ▼
The Springfield, IL metro has 70.1% good air days. Similar metros: Adrian, MI (69.3% good), Albany-Schenectady-Troy, NY (67.7% good), Ann Arbor, MI (69.3% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Springfield, IL, 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, Springfield, IL · 2020–2025