Median AQI
38
Good
Alaska · County air quality · 2025
Denali County, Alaska
Median AQI 38 (Good). 100.0% of monitored days rated Good, direct from EPA Air Quality System stations.
- 38
- Median AQI
- 100.0%
- Good-air days
- 0
- Unhealthy days
- 96%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Denali County's air is good on balance, among the cleanest 5% of US counties, a median AQI of 38 with 100.0% of 217 monitored days in the Good band, driven mainly by Ozone.
- 38
- median AQI · Good
- 100.0%
- days rated Good
- Ozone
- main pollutant
- 96%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 49.
Data updated July 2026
- Good · 217 d · 100.0%
How did Denali County's air break down in 2025?
Across 217 monitored days, 217 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 49 (Good).
EPA AQS →Air quality data from EPA Air Quality System (2025). 217 days monitored. Median AQI: 38 (Good).
Insights: Denali County, Alaska. EPA monitors recorded a median Air Quality Index of 38 across 217 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 217 (100%) fell in the Good band (AQI 0–50), 0 (0%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 44, while the worst single-day peak hit 49 (Good). Residents averaged about 30.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (217 days). Across the 2020–2025 trend window, good days shifted by -139 and the median AQI moved +5 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 49, good but never Unhealthy. Nearby counties show comparable readings: Aleutians East (95.0% good, AQI 11); Anchorage (80.8% good, AQI 24); Fairbanks North Star (61.5% good, AQI 42); Juneau (85.1% good, AQI 21); Kenai Peninsula (100.0% good, AQI 8); Matanuska-Susitna (90.3% good, AQI 7).
Air Quality Summary
Good Days
100.0%
217 of 217 monitored days
25.0pp vs 75% target
Max AQI Recorded
49
Good
Health Grade
Excellent
90th-pct AQI 44
Denali County, Good days share 100.0%
National avg
Share of monitored days at AQI 0-50 (Good band).
Denali 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 217 monitored days across EPA AQI categories.
Good
217
100%
Moderate
0
0%
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 Denali County.
- Ozone · 217 days · 100.0%
Health Impact Assessment
Excellent
Denali County's air quality is rated Excellent based on 100.0% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 100.0% of monitored days in 2025, with a median AQI of 38. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 217 of 217 monitored days.
5-Year Air Quality Trend
Air quality is stable in Denali County. Best year: 2021 (360 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 356 | 2 | 0 | 0 | 33 | 54 |
| 2021 | 360 | 3 | 0 | 0 | 33 | 74 |
| 2022 | 328 | 10 | 0 | 0 | 34 | 82 |
| 2023 | 350 | 0 | 0 | 0 | 33 | 50 |
| 2024 | 357 | 5 | 0 | 0 | 35 | 77 |
| 2025 | 217 | 0 | 0 | 0 | 38 | 49 |
How does Denali County compare?
How Denali County compares
Good-day share better than US avg
Denali County 100.0%
Aleutians East County, Alaska 95.0%
US average 76.5%
Median AQI about average
Denali County 38
Aleutians East County, Alaska 11
US average 38
Unhealthy days / yr about average
Denali County 0
Aleutians East County, Alaska 0
US average 0
Other Counties in Alaska
Air quality comparison for nearby counties in Alaska.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Denali County.
Adams County, Illinois
AQI 38 · 94.4% good
Anoka County, Minnesota
AQI 38 · 82.1% good
Atlantic County, New Jersey
AQI 38 · 79.6% good
Avery County, North Carolina
AQI 38 · 93.9% good
Barnstable County, Massachusetts
AQI 38 · 92.5% good
Bay County, Michigan
AQI 38 · 71.8% good
What Denali 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 38 means for exposure. Health guidance
- See how Denali County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Denali County with its Alaska neighbours before drawing a conclusion about the region. All of Alaska
Based on 217 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 Denali County, Alaska? ▼
Denali County has a median Air Quality Index (AQI) of 38, rated "Good." 100.0% of monitored days (217 out of 217) had good air quality in 2025.
What is the main pollutant in Denali County? ▼
The primary pollutant in Denali County is Ozone (O3), which was the main AQI driver on 217 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Denali County have? ▼
In 2025, Denali County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 49.
Is the air quality in Denali County getting better or worse? ▼
Air quality in Denali County is stable based on 5-year trends (2020-2025). Best year: 2021 with 360 good days. Worst year: 2025 with 217 good days.
What does AQI 38 mean for health? ▼
Denali County's median AQI of 38 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 Denali County compare to other counties in Alaska? ▼
Denali County has 100.0% good air days. Nearby counties in Alaska: Aleutians East (95.0% good), Anchorage (80.8% good), Fairbanks North Star (61.5% good), Juneau (85.1% good), Kenai Peninsula (100.0% good), Matanuska-Susitna (90.3% good).
What is the 90th percentile AQI in Denali County? ▼
The 90th percentile AQI for Denali County is 44, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 49 (Good).
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.