Median AQI
21
Good
Alaska · County air quality · 2025
Juneau County, Alaska
Median AQI 21 (Good). 85.1% of monitored days rated Good, direct from EPA Air Quality System stations.
- 21
- Median AQI
- 85.1%
- Good-air days
- 0
- Unhealthy days
- 66%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Juneau County's air is good on balance, cleaner than the median US county, a median AQI of 21 with 85.1% of 181 monitored days in the Good band, driven mainly by PM2.5.
- 21
- median AQI · Good
- 85.1%
- days rated Good
- PM2.5
- main pollutant
- 66%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 138.
Data updated July 2026
- Good · 154 d · 85.1%
- Moderate · 26 d · 14.4%
- USG · 1 d · 0.6%
How did Juneau County's air break down in 2025?
Across 181 monitored days, 154 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 138 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 21 (Good).
Insights: Juneau County, Alaska. EPA monitors recorded a median Air Quality Index of 21 across 181 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 154 (85%) fell in the Good band (AQI 0–50), 26 (14%) registered Moderate readings, and 1 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 57, while the worst single-day peak hit 138 (USG). Residents averaged about 25.5 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (181 days). Across the 2020–2025 trend window, good days shifted by -166 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 138, usg but never Unhealthy. Nearby counties show comparable readings: Aleutians East (95.0% good, AQI 11); Anchorage (80.8% good, AQI 24); Denali (100.0% good, AQI 38); Fairbanks North Star (61.5% good, AQI 42); Kenai Peninsula (100.0% good, AQI 8); Matanuska-Susitna (90.3% good, AQI 7).
Air Quality Summary
Good Days
85.1%
154 of 181 monitored days
10.1pp vs 75% target
Max AQI Recorded
138
USG
Health Grade
Good
90th-pct AQI 57
Juneau County, Good days share 85.1%
National avg
Share of monitored days at AQI 0-50 (Good band).
Juneau 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 181 monitored days across EPA AQI categories.
Good
154
85%
Moderate
26
14%
USG
1
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Juneau County.
- PM2.5 · 181 days · 100.0%
Health Impact Assessment
Good
Juneau County's air quality is rated Good based on 85.1% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 85.1% of monitored days in 2025, with a median AQI of 21. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 181 of 181 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Juneau County. Best year: 2020 (320 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 320 | 40 | 1 | 0 | 19 | 101 |
| 2021 | 315 | 42 | 0 | 0 | 20 | 89 |
| 2022 | 291 | 51 | 0 | 0 | 21 | 95 |
| 2023 | 314 | 50 | 0 | 0 | 24 | 78 |
| 2024 | 304 | 52 | 0 | 0 | 24 | 84 |
| 2025 | 154 | 26 | 1 | 0 | 21 | 138 |
How does Juneau County compare?
How Juneau County compares
Good-day share better than US avg
Juneau County 85.1%
Aleutians East County, Alaska 95.0%
US average 76.5%
Median AQI better than US avg
Juneau County 21
Aleutians East County, Alaska 11
US average 38
Unhealthy days / yr about average
Juneau 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 Juneau County.
Cowlitz County, Washington
AQI 21 · 91.6% good
Kitsap County, Washington
AQI 21 · 96.2% good
Marin County, California
AQI 21 · 100.0% good
Mason County, Washington
AQI 21 · 92.6% good
Pitkin County, Colorado
AQI 21 · 91.6% good
Putnam County, Florida
AQI 21 · 96.0% good
What Juneau County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 21 means for exposure. Health guidance
- See how Juneau County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Juneau County with its Alaska neighbours before drawing a conclusion about the region. All of Alaska
Based on 181 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 Juneau County, Alaska? ▼
Juneau County has a median Air Quality Index (AQI) of 21, rated "Good." 85.1% of monitored days (154 out of 181) had good air quality in 2025.
What is the main pollutant in Juneau County? ▼
The primary pollutant in Juneau County is Fine Particles (PM2.5), which was the main AQI driver on 181 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Juneau County have? ▼
In 2025, Juneau County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 138.
Is the air quality in Juneau County getting better or worse? ▼
Air quality in Juneau County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 320 good days. Worst year: 2025 with 154 good days.
What does AQI 21 mean for health? ▼
Juneau County's median AQI of 21 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 Juneau County compare to other counties in Alaska? ▼
Juneau County has 85.1% good air days. Nearby counties in Alaska: Aleutians East (95.0% good), Anchorage (80.8% good), Denali (100.0% good), Fairbanks North Star (61.5% good), Kenai Peninsula (100.0% good), Matanuska-Susitna (90.3% good).
What is the 90th percentile AQI in Juneau County? ▼
The 90th percentile AQI for Juneau County is 57, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 138 (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.
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.