Median AQI
48
Good
Colorado · County air quality · 2025
Clear Creek County, Colorado
Median AQI 48 (Good). 67.9% of monitored days rated Good, direct from EPA Air Quality System stations.
- 48
- Median AQI
- 67.9%
- Good-air days
- 0
- Unhealthy days
- 28%
- Cleaner than US counties
Clear Creek County's 2025 annual median AQI is 48 (Good), with 67.9% Good days
According to the U.S. EPA Air Quality System, Clear Creek County, Colorado posted a 2025 median AQI of 48 (Good) across 315 monitored days, with 67.9% 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
- Clear Creek County's 67.9% Good-day share places it cleaner than 28% of US counties in 2025.
- Closest median-AQI peer
- Adair County (55.8% Good, median AQI 48) is the closest nationwide median-AQI peer to Clear Creek County.
- 2020–2025 trend
- Clear Creek County's floor-qualifying Good-day share is improving from 2020 to 2025 (58.6% → 67.9%).
- Median AQI
- Median AQI: 48
The verdict
According to EPA Air Quality System monitoring data, Clear Creek County's air is good on balance, more polluted than the median US county, a median AQI of 48 with 67.9% of 315 monitored days in the Good band, driven mainly by Ozone.
- 48
- median AQI · Good
- 67.9%
- days rated Good
- Ozone
- main pollutant
- 28%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 100.
Annual release change
What changed in the 2025 EPA annual release
- Clear Creek County's Good-day share rose from 57.5% to 67.9% between the 2024 and 2025 EPA annual releases, a change of +10.4 percentage points.
- Clear Creek County's peak single-day AQI fell from 136 to 100 between the 2024 and 2025 EPA annual releases, a change of -36 points.
Data updated August 2026
- Good · 214 d · 67.9%
- Moderate · 101 d · 32.1%
How did Clear Creek County's air break down in 2025?
Across 315 monitored days, 214 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). 315 days monitored. Median AQI: 48 (Good).
Insights: Clear Creek County, Colorado. EPA monitors recorded a median Air Quality Index of 48 across 315 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 214 (68%) fell in the Good band (AQI 0–50), 101 (32%) 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 20.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (315 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by +9.4 points (measured against 239 monitored days in 2020 and 315 in 2025, so raw day counts are not comparable) 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 (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
67.9%
214 of 315 monitored days
-7.1pp vs 75% target
Max AQI Recorded
100
Moderate
Health Grade
Moderate
90th-pct AQI 67
Clear Creek County, Good days share 67.9%
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 315 monitored days across EPA AQI categories.
Good
214
68%
Moderate
101
32%
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 · 315 days · 100.0%
Health Impact Assessment
Moderate
Clear Creek County's air quality is rated Moderate based on 67.9% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 67.9% 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 315 of 315 monitored days.
5-Year Air Quality Trend
Air quality is improving in Clear Creek County. Highest Good-day share: 2022 (68.0%, 244 of 359 monitored 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 | 214 | 101 | 0 | 0 | 48 | 100 |
How does Clear Creek County compare?
How Clear Creek County compares
Good-day share worse than typical
Clear Creek County 67.9%
Adair County, Oklahoma 55.8%
Typical US county 76.0%
Median AQI worse than typical
Clear Creek County 48
Adair County, Oklahoma 48
Typical US county 39
Unhealthy days / yr better than typical
Clear Creek County 0
Adair County, Oklahoma 2
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Clear Creek County (48), not geographic neighbors.
Adair County, Oklahoma
Median AQI 48 · 55.8% Good-day share
Arapahoe County, Colorado
Median AQI 48 · 58.1% Good-day share
Arkansas County, Arkansas
Median AQI 48 · 52.9% Good-day share
Ashley County, Arkansas
Median AQI 48 · 55.7% Good-day share
Boulder County, Colorado
Median AQI 48 · 58.4% Good-day share
Bowie County, Texas
Median AQI 48 · 55.0% 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).
Hartford County, Connecticut
68.0% Good-day share · median AQI 42
San Juan County, New Mexico
68.0% Good-day share · median AQI 47
Warren County, Ohio
67.9% Good-day share · median AQI 44
Washington County, Oklahoma
68.0% Good-day share · median AQI 44
Douglas County, Colorado
67.7% Good-day share · median AQI 46
Preble County, Ohio
67.7% Good-day share · median AQI 43
Colorado counties on the map
Geographic containment only, other monitored counties in Colorado, independent of AQI or pollutant match.
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 315 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 Clear Creek County, Colorado? ▼
Clear Creek County has a median Air Quality Index (AQI) of 48, rated "Good." 67.9% of monitored days (214 out of 315) 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 315 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 across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2022 at 68.0% (244 of 359 days). Lowest qualifying Good-day share: 2023 at 56.8% (204 of 359 days).
What does AQI 48 mean for health? ▼
Clear Creek County's median AQI of 48 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Clear Creek County compare to other counties in Colorado? ▼
Clear Creek County has 67.9% 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 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. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Clear Creek 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.