Metro area air quality · 2025

Peoria, IL

Median AQI 45 (Good). 59.9% of monitored days rated Good across this metro's EPA monitoring network.

45
Median AQI
59.9%
Good-air days
2
Unhealthy days
25%
Cleaner than US metros

Peoria, IL posted a 2025 median AQI of 45 (Good) with 59.9% Good days

According to the U.S. EPA Air Quality System, the Peoria, IL CBSA recorded a median AQI of 45 across 357 monitored days in 2025, with 59.9% rated Good and 2 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 Peoria, IL CBSA's 59.9% Good-day share places it cleaner than 25% of US metros in 2025.
Closest median-AQI peer
Akron, OH (61.6% Good, median AQI 45) is the closest nationwide median-AQI peer to Peoria, IL.
2020–2025 Good-day shift
Peoria, IL's Good-day share moved -7.8 points from 2020 to 2025 (median AQI +1).
Median AQI
Median AQI: 45

Aggregated from EPA Air Quality System (2025), 357 monitored days. EPA AQS →

The verdict

The Peoria, IL metro runs good on the EPA scale, more polluted than the median US metro, a median AQI of 45 with 59.9% of 357 monitored days in the Good band.

45
median AQI · Good
59.9%
days rated Good
25%
cleaner than US metros
154
worst single reading

2 days reached Unhealthy or worse across the metro's monitors in 2025.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Peoria, IL metro's Good-day share fell from 68.6% to 60.3% between the 2024 and 2025 EPA annual releases, a change of -8.3 percentage points.
  • Peoria, IL metro's peak single-day AQI rose from 100 to 154 between the 2024 and 2025 EPA annual releases, a change of +54 points.
  • Peoria, IL metro's Unhealthy-category days rose from 0 to 2 between the 2024 and 2025 EPA annual releases, a change of +2 days.

Compared against 344 monitored days in 2024 and 355 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

Insights: Peoria, IL metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 45 over 357 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 214 Good days (60%), 139 Moderate (39%), and 2 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 66 while the highest single-day reading hit 154 (Unhealthy). Metro residents averaged roughly 18.0 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -7.8 points and the median AQI moved +1 points, which classifies the multi-year trajectory as worsening. The annual record contains 2 days at Unhealthy or worse. On those days, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Metros with comparable AQI profiles include Akron, OH (61.6% good, AQI 45); Ardmore, OK (67.9% good, AQI 45); Asheville, NC (69.9% good, AQI 45).

Air Quality Summary

Median AQI

45

Good

Good Days

59.9%

214 of 357 days

Max AQI

154

Unhealthy

Health Grade

Moderate

90th pct: 66

AQI Day Breakdown (2025)

Distribution of 357 monitored days across EPA AQI categories.

Good

214

60%

Moderate

139

39%

USG

2

1%

Unhealthy

2

1%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Peoria, IL metro area's air quality is rated Moderate based on 59.9% good air days. There were 2 unhealthy days in 2025 when outdoor activity should be limited.

Air quality is acceptable most days, but 2 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 154. Sensitive groups should monitor real-time conditions at AirNow.gov.

How does the Peoria, IL metro compare?

How Peoria, IL compares

Good-day share worse than typical
Peoria, IL 59.9%
Akron, OH 61.6%
Typical US metro 70.6%
Median AQI worse than typical
Peoria, IL 45
Akron, OH 45
Typical US metro 41
Unhealthy days / yr worse than typical
Peoria, IL 2
Akron, OH 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Peoria, IL metro. Highest Good-day share: 2024 (68.6%, 236 of 344 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 247 116 0 44
2021 181 179 0 50
2022 181 138 0 48
2023 187 131 1 48
2024 236 108 0 44
2025 214 139 2 45

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Peoria, IL (45).

Akron, OH

Median AQI 45 · 61.6% Good-day share

45

Ardmore, OK

Median AQI 45 · 67.9% Good-day share

45

Asheville, NC

Median AQI 45 · 69.9% Good-day share

45

Cheyenne, WY

Median AQI 45 · 75.1% Good-day share

45

Clinton, IA

Median AQI 45 · 59.5% Good-day share

45

Fort Dodge, IA

Median AQI 45 · 59.2% Good-day share

45

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Peoria, IL's 2 (independent of median AQI).

Bridgeport-Stamford-Norwalk, CT

2 unhealthy-or-worse days · median AQI 44

44

Chattanooga, TN-GA

2 unhealthy-or-worse days · median AQI 49

49

Cincinnati, OH-KY-IN

2 unhealthy-or-worse days · median AQI 56

56

Columbus, GA-AL

2 unhealthy-or-worse days · median AQI 48

48

Davenport-Moline-Rock Island, IA-IL

2 unhealthy-or-worse days · median AQI 46

46

Grand Rapids-Wyoming, MI

2 unhealthy-or-worse days · median AQI 52

52

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 Peoria, IL metro area? ▼
The Peoria, IL metro area has a median Air Quality Index (AQI) of 45, rated "Good." 59.9% of monitored days (214 out of 357) had good air quality in 2025.
How many unhealthy air days does Peoria, IL have? ▼
In 2025, the Peoria, IL metro area recorded 2 unhealthy air days (2 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 154.
Is air quality in Peoria, IL getting better or worse? ▼
Air quality in the Peoria, IL metro is worsening 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 68.6% (236 of 344 days). Lowest qualifying Good-day share: 2021 at 50.3% (181 of 360 days).
What does AQI 45 mean for health? ▼
An AQI of 45 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 Peoria, IL? ▼
The 90th percentile AQI for the Peoria, IL metro area is 66, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 154 (Unhealthy).
How does Peoria, IL compare to other metro areas? ▼
The Peoria, IL metro has 59.9% good air days. Similar metros: Akron, OH (61.6% good), Ardmore, OK (67.9% good), Asheville, NC (69.9% 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

Share this annual record

Send the source-year summary or download its ready-to-use data card.

XFacebookLinkedInWhatsAppEmail

Every figure on PlainAirData 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.