Median AQI
48
Good
Colorado · County air quality · 2025
Clear Creek County, Colorado
Median AQI 48 (Good). 64.4% of monitored days rated Good, direct from EPA Air Quality System stations.
- 48
- Median AQI
- 64.4%
- Good-air days
- 0
- Unhealthy days
- 22%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Clear Creek County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 48 with 64.4% of 267 monitored days in the Good band, driven mainly by Ozone.
- 48
- median AQI · Good
- 64.4%
- 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 100.
Data updated July 2026
- Good · 172 d · 64.4%
- Moderate · 95 d · 35.6%
How did Clear Creek County's air break down in 2025?
Across 267 monitored days, 172 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 100 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 267 days monitored. Median AQI: 48 (Good).
Insights: Clear Creek County, Colorado. EPA monitors recorded a median Air Quality Index of 48 across 267 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 172 (64%) fell in the Good band (AQI 0–50), 95 (36%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 67, while the worst single-day peak hit 100 (Moderate). Residents averaged about 19.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (267 days). Across the 2020–2025 trend window, good days shifted by +32 and the median AQI moved -1 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 100, 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); Delta (88.0% good, AQI 28).
Air Quality Summary
Good Days
64.4%
172 of 267 monitored days
-10.6pp vs 75% target
Max AQI Recorded
100
Moderate
Health Grade
Moderate
90th-pct AQI 67
Clear Creek County, Good days share 64.4%
National avg
Share of monitored days at AQI 0-50 (Good band).
Clear Creek 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 267 monitored days across EPA AQI categories.
Good
172
64%
Moderate
95
36%
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 Clear Creek County.
- Ozone · 267 days · 100.0%
Health Impact Assessment
Moderate
Clear Creek County's air quality is rated Moderate based on 64.4% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 64.4% of monitored days in 2025, with a median AQI of 48. 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 267 monitored days.
5-Year Air Quality Trend
Air quality is improving in Clear Creek County. Best year: 2022 (244 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 140 | 87 | 10 | 2 | 49 | 156 |
| 2021 | 206 | 127 | 22 | 2 | 49 | 154 |
| 2022 | 244 | 110 | 5 | 0 | 47 | 126 |
| 2023 | 204 | 147 | 8 | 0 | 49 | 136 |
| 2024 | 202 | 139 | 10 | 0 | 49 | 136 |
| 2025 | 172 | 95 | 0 | 0 | 48 | 100 |
How does Clear Creek County compare?
How Clear Creek County compares
Good-day share worse than US avg
Clear Creek County 64.4%
Adams County, Colorado 50.2%
US average 76.5%
Median AQI worse than US avg
Clear Creek County 48
Adams County, Colorado 50
US average 38
Unhealthy days / yr about average
Clear Creek 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 Clear Creek County.
Black Hawk County, Iowa
AQI 48 · 56.6% good
Box Elder County, Utah
AQI 48 · 60.0% good
Brookings County, South Dakota
AQI 48 · 53.0% good
Coconino County, Arizona
AQI 48 · 62.5% good
Columbia County, Florida
AQI 48 · 56.4% good
Davis County, Utah
AQI 48 · 59.5% good
What Clear Creek 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 48 means for exposure. Health guidance
- See how Clear Creek County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Clear Creek County with its Colorado neighbours before drawing a conclusion about the region. All of Colorado
Based on 267 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 Clear Creek County, Colorado? ▼
Clear Creek County has a median Air Quality Index (AQI) of 48, rated "Good." 64.4% of monitored days (172 out of 267) had good air quality in 2025.
What is the main pollutant in Clear Creek County? ▼
The primary pollutant in Clear Creek 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 Clear Creek County have? ▼
In 2025, Clear Creek County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 100.
Is the air quality in Clear Creek County getting better or worse? ▼
Air quality in Clear Creek County is improving based on 5-year trends (2020-2025). Best year: 2022 with 244 good days. Worst year: 2020 with 140 good days.
What does AQI 48 mean for health? ▼
Clear Creek County's median AQI of 48 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 Clear Creek County compare to other counties in Colorado? ▼
Clear Creek County has 64.4% 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), Delta (88.0% good).
What is the 90th percentile AQI in Clear Creek County? ▼
The 90th percentile AQI for Clear Creek County is 67, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 100 (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.