Median AQI
44
Good
Ohio · County air quality · 2025
Summit County, Ohio
Median AQI 44 (Good). 64.5% of monitored days rated Good, direct from EPA Air Quality System stations.
- 44
- Median AQI
- 64.5%
- Good-air days
- 0
- Unhealthy days
- 22%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Summit County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 44 with 64.5% of 304 monitored days in the Good band, driven mainly by Ozone.
- 44
- median AQI · Good
- 64.5%
- days rated Good
- Ozone
- main pollutant
- 22%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 126.
Data updated July 2026
- Good · 196 d · 64.5%
- Moderate · 105 d · 34.5%
- USG · 3 d · 1.0%
How did Summit County's air break down in 2025?
Across 304 monitored days, 196 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 126 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 304 days monitored. Median AQI: 44 (Good).
Insights: Summit County, Ohio. EPA monitors recorded a median Air Quality Index of 44 across 304 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 196 (64%) fell in the Good band (AQI 0–50), 105 (35%) registered Moderate readings, and 3 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 68, while the worst single-day peak hit 126 (USG). Residents averaged about 19.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (154 days), PM2.5 (150 days). Across the 2020–2025 trend window, good days shifted by +3 and the median AQI moved -4 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 126, usg but never Unhealthy. Nearby counties show comparable readings: Allen (65.9% good, AQI 43); Ashtabula (81.2% good, AQI 43); Athens (80.3% good, AQI 33); Belmont (63.0% good, AQI 42); Butler (33.3% good, AQI 55); Clark (59.4% good, AQI 46).
Air Quality Summary
Good Days
64.5%
196 of 304 monitored days
-10.5pp vs 75% target
Max AQI Recorded
126
USG
Health Grade
Moderate
90th-pct AQI 68
Summit County, Good days share 64.5%
National avg
Share of monitored days at AQI 0-50 (Good band).
Summit County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 304 monitored days across EPA AQI categories.
Good
196
64%
Moderate
105
35%
USG
3
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Summit County.
- Ozone · 154 days · 50.7%
- PM2.5 · 150 days · 49.3%
Health Impact Assessment
Moderate
Summit County's air quality is rated Moderate based on 64.5% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 64.5% of monitored days in 2025, with a median AQI of 44. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 154 of 304 monitored days.
5-Year Air Quality Trend
Air quality is improving in Summit County. Best year: 2022 (231 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 193 | 165 | 3 | 0 | 48 | 114 |
| 2021 | 223 | 130 | 3 | 0 | 45 | 105 |
| 2022 | 231 | 128 | 3 | 0 | 43 | 133 |
| 2023 | 209 | 131 | 5 | 2 | 46 | 230 |
| 2024 | 224 | 116 | 1 | 0 | 44 | 105 |
| 2025 | 196 | 105 | 3 | 0 | 44 | 126 |
How does Summit County compare?
How Summit County compares
Good-day share worse than US avg
Summit County 64.5%
Allen County, Ohio 65.9%
US average 76.5%
Median AQI worse than US avg
Summit County 44
Allen County, Ohio 43
US average 38
Unhealthy days / yr about average
Summit County 0
Allen County, Ohio 0
US average 0
Other Counties in Ohio
Air quality comparison for nearby counties in Ohio.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Summit County.
Baltimore County, Maryland
AQI 44 · 70.4% good
Baltimore (City) County, Maryland
AQI 44 · 68.7% good
Bartholomew County, Indiana
AQI 44 · 69.2% good
Berks County, Pennsylvania
AQI 44 · 65.6% good
Bolivar County, Mississippi
AQI 44 · 70.3% good
Brewster County, Texas
AQI 44 · 69.0% good
What Summit County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 44 means for exposure. Health guidance
- See how Summit County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Summit County with its Ohio neighbours before drawing a conclusion about the region. All of Ohio
Based on 304 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Summit County, Ohio? ▼
Summit County has a median Air Quality Index (AQI) of 44, rated "Good." 64.5% of monitored days (196 out of 304) had good air quality in 2025.
What is the main pollutant in Summit County? ▼
The primary pollutant in Summit County is Ozone (O3), which was the main AQI driver on 154 days (51% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Summit County have? ▼
In 2025, Summit County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 126.
Is the air quality in Summit County getting better or worse? ▼
Air quality in Summit County is improving based on 5-year trends (2020-2025). Best year: 2022 with 231 good days. Worst year: 2020 with 193 good days.
What does AQI 44 mean for health? ▼
Summit County's median AQI of 44 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Summit County compare to other counties in Ohio? ▼
Summit County has 64.5% good air days. Nearby counties in Ohio: Allen (65.9% good), Ashtabula (81.2% good), Athens (80.3% good), Belmont (63.0% good), Butler (33.3% good), Clark (59.4% good).
What is the 90th percentile AQI in Summit County? ▼
The 90th percentile AQI for Summit County is 68, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 126 (USG).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
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.