Median AQI
49
Good
Colorado · County air quality · 2025
Gunnison County, Colorado
Median AQI 49 (Good). 59.9% of monitored days rated Good, direct from EPA Air Quality System stations.
- 49
- Median AQI
- 59.9%
- Good-air days
- 0
- Unhealthy days
- 15%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Gunnison County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 49 with 59.9% of 242 monitored days in the Good band, driven mainly by Ozone.
- 49
- median AQI · Good
- 59.9%
- days rated Good
- Ozone
- main pollutant
- 15%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 115.
Data updated July 2026
- Good · 145 d · 59.9%
- Moderate · 96 d · 39.7%
- USG · 1 d · 0.4%
How did Gunnison County's air break down in 2025?
Across 242 monitored days, 145 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 115 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 242 days monitored. Median AQI: 49 (Good).
Insights: Gunnison County, Colorado. EPA monitors recorded a median Air Quality Index of 49 across 242 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 145 (60%) fell in the Good band (AQI 0–50), 96 (40%) registered Moderate readings, and 1 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 71, while the worst single-day peak hit 115 (USG). Residents averaged about 18.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (242 days). Across the 2020–2025 trend window, good days shifted by -125 and the median AQI moved +5 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 115, usg but never Unhealthy. Nearby counties show comparable readings: Adams (50.2% good, AQI 50); Alamosa (90.8% good, AQI 24); Arapahoe (47.3% good, AQI 51); Archuleta (79.5% good, AQI 32); Boulder (50.9% good, AQI 50); Clear Creek (64.4% good, AQI 48).
Air Quality Summary
Good Days
59.9%
145 of 242 monitored days
-15.1pp vs 75% target
Max AQI Recorded
115
USG
Health Grade
Moderate
90th-pct AQI 71
Gunnison County, Good days share 59.9%
National avg
Share of monitored days at AQI 0-50 (Good band).
Gunnison 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 242 monitored days across EPA AQI categories.
Good
145
60%
Moderate
96
40%
USG
1
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Gunnison County.
- Ozone · 242 days · 100.0%
Health Impact Assessment
Moderate
Gunnison County's air quality is rated Moderate based on 59.9% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 59.9% of monitored days in 2025, with a median AQI of 49. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 242 of 242 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Gunnison County. Best year: 2022 (281 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 270 | 62 | 3 | 0 | 44 | 115 |
| 2021 | 262 | 102 | 1 | 0 | 46 | 101 |
| 2022 | 281 | 82 | 2 | 0 | 46 | 108 |
| 2023 | 251 | 112 | 0 | 0 | 46 | 93 |
| 2024 | 243 | 123 | 0 | 0 | 47 | 100 |
| 2025 | 145 | 96 | 1 | 0 | 49 | 115 |
How does Gunnison County compare?
How Gunnison County compares
Good-day share worse than US avg
Gunnison County 59.9%
Adams County, Colorado 50.2%
US average 76.5%
Median AQI worse than US avg
Gunnison County 49
Adams County, Colorado 50
US average 38
Unhealthy days / yr about average
Gunnison County 0
Adams County, Colorado 0
US average 0
Other Counties in Colorado
Air quality comparison for nearby counties in Colorado.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Gunnison County.
Allegheny County, Pennsylvania
AQI 49 · 51.6% good
Arkansas County, Arkansas
AQI 49 · 51.6% good
Ashley County, Arkansas
AQI 49 · 53.9% good
Clayton County, Georgia
AQI 49 · 53.1% good
Cleveland County, Oklahoma
AQI 49 · 53.7% good
Dewey County, Oklahoma
AQI 49 · 56.6% good
What Gunnison 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 49 means for exposure. Health guidance
- See how Gunnison County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Gunnison County with its Colorado neighbours before drawing a conclusion about the region. All of Colorado
Based on 242 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 Gunnison County, Colorado? ▼
Gunnison County has a median Air Quality Index (AQI) of 49, rated "Good." 59.9% of monitored days (145 out of 242) had good air quality in 2025.
What is the main pollutant in Gunnison County? ▼
The primary pollutant in Gunnison County is Ozone (O3), which was the main AQI driver on 242 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Gunnison County have? ▼
In 2025, Gunnison County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 115.
Is the air quality in Gunnison County getting better or worse? ▼
Air quality in Gunnison County is worsening based on 5-year trends (2020-2025). Best year: 2022 with 281 good days. Worst year: 2025 with 145 good days.
What does AQI 49 mean for health? ▼
Gunnison County's median AQI of 49 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 Gunnison County compare to other counties in Colorado? ▼
Gunnison County has 59.9% good air days. Nearby counties in Colorado: Adams (50.2% good), Alamosa (90.8% good), Arapahoe (47.3% good), Archuleta (79.5% good), Boulder (50.9% good), Clear Creek (64.4% good).
What is the 90th percentile AQI in Gunnison County? ▼
The 90th percentile AQI for Gunnison County is 71, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 115 (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.