Median AQI
44
Good
Colorado · County air quality · 2025
Garfield County, Colorado
Median AQI 44 (Good). 76.5% of monitored days rated Good, direct from EPA Air Quality System stations.
- 44
- Median AQI
- 76.5%
- Good-air days
- 0
- Unhealthy days
- 43%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Garfield County's air is good on balance, more polluted than the median US county, a median AQI of 44 with 76.5% of 268 monitored days in the Good band, driven mainly by Ozone.
- 44
- median AQI · Good
- 76.5%
- days rated Good
- Ozone
- main pollutant
- 43%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 93.
Data updated July 2026
- Good · 205 d · 76.5%
- Moderate · 63 d · 23.5%
How did Garfield County's air break down in 2025?
Across 268 monitored days, 205 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 93 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 268 days monitored. Median AQI: 44 (Good).
Insights: Garfield County, Colorado. EPA monitors recorded a median Air Quality Index of 44 across 268 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 205 (76%) fell in the Good band (AQI 0–50), 63 (24%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 64, while the worst single-day peak hit 93 (Moderate). Residents averaged about 22.9 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (267 days), PM2.5 (1 days). Across the 2020–2025 trend window, good days shifted by -27 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 93, moderate 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
76.5%
205 of 268 monitored days
1.5pp vs 75% target
Max AQI Recorded
93
Moderate
Health Grade
Good
90th-pct AQI 64
Garfield County, Good days share 76.5%
National avg
Share of monitored days at AQI 0-50 (Good band).
Garfield 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 268 monitored days across EPA AQI categories.
Good
205
76%
Moderate
63
24%
USG
0
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 Garfield County.
- Ozone · 267 days · 99.6%
- PM2.5 · 1 days · 0.4%
Health Impact Assessment
Good
Garfield County's air quality is rated Good based on 76.5% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 76.5% 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 267 of 268 monitored days.
5-Year Air Quality Trend
Air quality is improving in Garfield County. Best year: 2020 (232 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 232 | 129 | 5 | 0 | 48 | 150 |
| 2021 | 198 | 156 | 10 | 1 | 49 | 158 |
| 2022 | 221 | 142 | 2 | 0 | 49 | 108 |
| 2023 | 166 | 196 | 3 | 0 | 54 | 126 |
| 2024 | 216 | 145 | 5 | 0 | 49 | 133 |
| 2025 | 205 | 63 | 0 | 0 | 44 | 93 |
How does Garfield County compare?
How Garfield County compares
Good-day share about average
Garfield County 76.5%
Adams County, Colorado 50.2%
US average 76.5%
Median AQI worse than US avg
Garfield County 44
Adams County, Colorado 50
US average 38
Unhealthy days / yr about average
Garfield 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 Garfield 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 Garfield 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 Garfield County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Garfield County with its Colorado neighbours before drawing a conclusion about the region. All of Colorado
Based on 268 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 Garfield County, Colorado? ▼
Garfield County has a median Air Quality Index (AQI) of 44, rated "Good." 76.5% of monitored days (205 out of 268) had good air quality in 2025.
What is the main pollutant in Garfield County? ▼
The primary pollutant in Garfield County is Ozone (O3), which was the main AQI driver on 267 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Garfield County have? ▼
In 2025, Garfield County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 93.
Is the air quality in Garfield County getting better or worse? ▼
Air quality in Garfield County is improving based on 5-year trends (2020-2025). Best year: 2020 with 232 good days. Worst year: 2023 with 166 good days.
What does AQI 44 mean for health? ▼
Garfield 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 Garfield County compare to other counties in Colorado? ▼
Garfield County has 76.5% 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 Garfield County? ▼
The 90th percentile AQI for Garfield County is 64, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 93 (Moderate).
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.