Metro area air quality · 2025

Springfield, IL

Median AQI 42 (Good). 70.7% of monitored days rated Good across this metro's EPA monitoring network.

42
Median AQI
70.7%
Good-air days
0
Unhealthy days
45%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 273 monitored days. EPA AQS →

The verdict

The Springfield, IL metro runs good on the EPA scale, more polluted than the median US metro, a median AQI of 42 with 70.7% of 273 monitored days in the Good band.

42
median AQI · Good
70.7%
days rated Good
45%
cleaner than US metros
142
worst single reading

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

Insights: Springfield, IL metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 42 over 273 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 193 Good days (71%), 77 Moderate (28%), and 3 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 61 while the highest single-day reading hit 142 (USG). Metro residents averaged roughly 21.2 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -61 and the median AQI moved -2 points, which classifies the multi-year trajectory as stable. 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 Albany-Schenectady-Troy, NY (66.3% good, AQI 42); Bismarck, ND (75.8% good, AQI 42); Bloomington, IN (70.1% good, AQI 42).

Air Quality Summary

Median AQI

42

Good

Good Days

70.7%

193 of 273 days

Max AQI

142

USG

Health Grade

Moderate

90th pct: 61

AQI Day Breakdown (2025)

Distribution of 273 monitored days across EPA AQI categories.

Good

193

71%

Moderate

77

28%

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 70.7% 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 Springfield, IL metro compare?

How Springfield, IL compares

Good-day share worse than US avg
Springfield, IL 70.7%
Albany-Schenectady-Troy, NY 66.3%
US average 71.3%
Median AQI worse than US avg
Springfield, IL 42
Albany-Schenectady-Troy, NY 42
US average 41
Unhealthy days / yr better than US avg
Springfield, IL 0
Albany-Schenectady-Troy, NY 0
US average 1

5-Year Air Quality Trend

Air quality is stable in the Springfield, IL metro. Best year: 2024 (263 good 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 193 77 0 42

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Springfield, IL.

Albany-Schenectady-Troy, NY

AQI 42 · 66.3% good

42

Bismarck, ND

AQI 42 · 75.8% good

42

Bloomington, IN

AQI 42 · 70.1% good

42

Cape Coral-Fort Myers, FL

AQI 42 · 74.4% good

42

Daphne-Fairhope-Foley, AL

AQI 42 · 72.2% good

42

Decatur, AL

AQI 42 · 81.1% good

42

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Cleanest Metro Areas

U.S. metros ranked by their share of Good air-quality days.

Worst Air Quality

Counties and metros with the most unhealthy air days.

All Metro Areas

Annual AQI by CBSA for every monitored U.S. metro area.

Best and Worst City Air

What drives urban air quality and how metro areas compare.

Air Quality Guides

Frequently Asked Questions

What is the air quality in the Springfield, IL metro area? ▼
The Springfield, IL metro area has a median Air Quality Index (AQI) of 42, rated "Good." 70.7% of monitored days (193 out of 273) had good air quality in 2025.
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.
Is air quality in Springfield, IL getting better or worse? ▼
Air quality in the Springfield, IL metro is stable based on 5-year trends (2020-2025). Best year: 2024 with 263 good days. Worst year: 2023 with 182 good days.
What does AQI 42 mean for health? ▼
An AQI of 42 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
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 does Springfield, IL compare to other metro areas? ▼
The Springfield, IL metro has 70.7% good air days. Similar metros: Albany-Schenectady-Troy, NY (66.3% good), Bismarck, ND (75.8% good), Bloomington, IN (70.1% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. 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 files (metro-level) · 2020–2025

Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.