Metro area air quality · 2025

Lima, OH

Median AQI 43 (Good). 65.9% of monitored days rated Good across this metro's EPA monitoring network.

43
Median AQI
65.9%
Good-air days
0
Unhealthy days
36%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 296 monitored days. EPA AQS →

The verdict

The Lima, OH metro runs good on the EPA scale, more polluted than the median US metro, a median AQI of 43 with 65.9% of 296 monitored days in the Good band.

43
median AQI · Good
65.9%
days rated Good
36%
cleaner than US metros
129
worst single reading

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

Insights: Lima, OH metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 43 over 296 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 195 Good days (66%), 100 Moderate (34%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 63 while the highest single-day reading hit 129 (USG). Metro residents averaged roughly 19.8 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -94 and the median AQI moved +3 points, which classifies the multi-year trajectory as worsening. 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 Allentown-Bethlehem-Easton, PA-NJ (65.6% good, AQI 43); Amarillo, TX (75.7% good, AQI 43); Ashtabula, OH (81.2% good, AQI 43).

Air Quality Summary

Median AQI

43

Good

Good Days

65.9%

195 of 296 days

Max AQI

129

USG

Health Grade

Moderate

90th pct: 63

AQI Day Breakdown (2025)

Distribution of 296 monitored days across EPA AQI categories.

Good

195

66%

Moderate

100

34%

USG

1

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Lima, OH metro area's air quality is rated Moderate based on 65.9% 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 Lima, OH metro compare?

How Lima, OH compares

Good-day share worse than US avg
Lima, OH 65.9%
Allentown-Bethlehem-Easton, PA-NJ 65.6%
US average 71.3%
Median AQI worse than US avg
Lima, OH 43
Allentown-Bethlehem-Easton, PA-NJ 43
US average 41
Unhealthy days / yr better than US avg
Lima, OH 0
Allentown-Bethlehem-Easton, PA-NJ 0
US average 1

5-Year Air Quality Trend

Air quality is worsening in the Lima, OH metro. Best year: 2020 (289 good days).

Year Good Moderate Unhealthy Median AQI
2020 289 70 0 40
2021 260 105 0 42
2022 272 93 0 41
2023 252 105 3 44
2024 275 84 0 42
2025 195 100 0 43

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Lima, OH.

Allentown-Bethlehem-Easton, PA-NJ

AQI 43 · 65.6% good

43

Amarillo, TX

AQI 43 · 75.7% good

43

Ashtabula, OH

AQI 43 · 81.2% good

43

College Station-Bryan, TX

AQI 43 · 63.4% good

43

Fallon, NV

AQI 43 · 81.0% good

43

Gillette, WY

AQI 43 · 77.3% good

43

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 Lima, OH metro area? ▼
The Lima, OH metro area has a median Air Quality Index (AQI) of 43, rated "Good." 65.9% of monitored days (195 out of 296) had good air quality in 2025.
How many unhealthy air days does Lima, OH have? ▼
In 2025, the Lima, OH metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 129.
Is air quality in Lima, OH getting better or worse? ▼
Air quality in the Lima, OH metro is worsening based on 5-year trends (2020-2025). Best year: 2020 with 289 good days. Worst year: 2025 with 195 good 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.
What is the 90th percentile AQI for Lima, OH? ▼
The 90th percentile AQI for the Lima, OH metro area is 63, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 129 (USG).
How does Lima, OH compare to other metro areas? ▼
The Lima, OH metro has 65.9% good air days. Similar metros: Allentown-Bethlehem-Easton, PA-NJ (65.6% good), Amarillo, TX (75.7% good), Ashtabula, OH (81.2% 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.