Median AQI
46
Good
Colorado · County air quality · 2025
Gunnison County, Colorado
Median AQI 46 (Good). 72.5% of monitored days rated Good, direct from EPA Air Quality System stations.
- 46
- Median AQI
- 72.5%
- Good-air days
- 0
- Unhealthy days
- 38%
- Cleaner than US counties
Gunnison County's 2025 annual median AQI is 46 (Good), with 72.5% Good days
According to the U.S. EPA Air Quality System, Gunnison County, Colorado posted a 2025 median AQI of 46 (Good) across 364 monitored days, with 72.5% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Gunnison County's 72.5% Good-day share places it cleaner than 38% of US counties in 2025.
- Closest median-AQI peer
- Beaver County (55.6% Good, median AQI 46) is the closest nationwide median-AQI peer to Gunnison County.
- 2020–2025 trend
- Gunnison County's floor-qualifying Good-day share is worsening from 2020 to 2025 (80.6% → 72.5%).
- Median AQI
- Median AQI: 46
The verdict
According to EPA Air Quality System monitoring data, Gunnison County's air is good on balance, more polluted than the median US county, a median AQI of 46 with 72.5% of 364 monitored days in the Good band, driven mainly by Ozone.
- 46
- median AQI · Good
- 72.5%
- days rated Good
- Ozone
- main pollutant
- 38%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 115.
Annual release change
What changed in the 2025 EPA annual release
- Gunnison County's Good-day share rose from 66.4% to 72.5% between the 2024 and 2025 EPA annual releases, a change of +6.1 percentage points.
- Gunnison County's peak single-day AQI rose from 100 to 115 between the 2024 and 2025 EPA annual releases, a change of +15 points.
Data updated August 2026
- Good · 264 d · 72.5%
- Moderate · 99 d · 27.2%
- USG · 1 d · 0.3%
How did Gunnison County's air break down in 2025?
Across 364 monitored days, 264 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). 364 days monitored. Median AQI: 46 (Good).
Insights: Gunnison County, Colorado. EPA monitors recorded a median Air Quality Index of 46 across 364 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 264 (73%) fell in the Good band (AQI 0–50), 99 (27%) registered Moderate readings, and 1 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 67, while the worst single-day peak hit 115 (USG). Residents averaged about 21.8 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (364 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -8.1 points (measured against 335 monitored days in 2020 and 364 in 2025, so raw day counts are not comparable) and the median AQI moved +2 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 (55.1% good, AQI 49); Alamosa (91.5% good, AQI 25); Arapahoe (58.1% good, AQI 48); Archuleta (83.0% good, AQI 34); Boulder (58.4% good, AQI 48); Chaffee (66.0% good, AQI 48).
Air Quality Summary
Good Days
72.5%
264 of 364 monitored days
-2.5pp vs 75% target
Max AQI Recorded
115
USG
Health Grade
Moderate
90th-pct AQI 67
Gunnison County, Good days share 72.5%
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 364 monitored days across EPA AQI categories.
Good
264
73%
Moderate
99
27%
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 · 364 days · 100.0%
Health Impact Assessment
Moderate
Gunnison County's air quality is rated Moderate based on 72.5% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 72.5% of monitored days in 2025, with a median AQI of 46. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 364 of 364 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Gunnison County. Highest Good-day share: 2020 (80.6%, 270 of 335 monitored 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 | 264 | 99 | 1 | 0 | 46 | 115 |
How does Gunnison County compare?
How Gunnison County compares
Good-day share worse than US avg
Gunnison County 72.5%
Beaver County, Pennsylvania 55.6%
US average 76.0%
Median AQI worse than US avg
Gunnison County 46
Beaver County, Pennsylvania 46
US average 39
Unhealthy days / yr better than US avg
Gunnison County 0
Beaver County, Pennsylvania 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Gunnison County (46), not geographic neighbors.
Beaver County, Pennsylvania
Median AQI 46 · 55.6% Good-day share
Brookings County, South Dakota
Median AQI 46 · 58.6% Good-day share
Buchanan County, Missouri
Median AQI 46 · 56.4% Good-day share
Butte County, California
Median AQI 46 · 65.2% Good-day share
Clark County, Indiana
Median AQI 46 · 58.1% Good-day share
Clarke County, Georgia
Median AQI 46 · 57.8% Good-day share
Same primary pollutant: Ozone
Ozone led the AQI on the most monitored days here. These peers share that driver and the closest Good-day share (a second relationship type beyond median-AQI neighbors).
Bartholomew County, Indiana
72.6% Good-day share · median AQI 43
Ingham County, Michigan
72.6% Good-day share · median AQI 38
Mercer County, Pennsylvania
72.6% Good-day share · median AQI 42
Suffolk County, New York
72.6% Good-day share · median AQI 41
Jersey County, Illinois
72.3% Good-day share · median AQI 42
Dodge County, Wisconsin
72.3% Good-day share · median AQI 40
Colorado counties on the map
Geographic containment only, other monitored counties in Colorado, independent of AQI or pollutant match.
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 46 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 364 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
Keep exploring the annual AQI record
Air-quality reading list
Frequently Asked Questions
What is the air quality in Gunnison County, Colorado? ▼
Gunnison County has a median Air Quality Index (AQI) of 46, rated "Good." 72.5% of monitored days (264 out of 364) 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 364 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 across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 80.6% (270 of 335 days). Lowest qualifying Good-day share: 2024 at 66.4% (243 of 366 days).
What does AQI 46 mean for health? ▼
Gunnison County's median AQI of 46 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Gunnison County compare to other counties in Colorado? ▼
Gunnison County has 72.5% good air days. Nearby counties in Colorado: Adams (55.1% good), Alamosa (91.5% good), Arapahoe (58.1% good), Archuleta (83.0% good), Boulder (58.4% good), Chaffee (66.0% good).
What is the 90th percentile AQI in Gunnison County? ▼
The 90th percentile AQI for Gunnison County is 67, 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. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Gunnison County, Colorado · 2020–2025
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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.