Median AQI
7
Good
Alaska · County air quality · 2025
Matanuska-Susitna County, Alaska
Median AQI 7 (Good). 90.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 7
- Median AQI
- 90.3%
- Good-air days
- 0
- Unhealthy days
- 76%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Matanuska-Susitna County's air is good on balance, cleaner than most US counties, a median AQI of 7 with 90.3% of 176 monitored days in the Good band, driven mainly by PM2.5.
- 7
- median AQI · Good
- 90.3%
- days rated Good
- PM2.5
- main pollutant
- 76%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 141.
Data updated July 2026
- Good · 159 d · 90.3%
- Moderate · 15 d · 8.5%
- USG · 2 d · 1.1%
How did Matanuska-Susitna County's air break down in 2025?
Across 176 monitored days, 159 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 141 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 176 days monitored. Median AQI: 7 (Good).
Insights: Matanuska-Susitna County, Alaska. EPA monitors recorded a median Air Quality Index of 7 across 176 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 159 (90%) fell in the Good band (AQI 0–50), 15 (9%) registered Moderate readings, and 2 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 48, while the worst single-day peak hit 141 (USG). Residents averaged about 27.1 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (89 days), PM10 (87 days). Across the 2020–2025 trend window, good days shifted by -158 and the median AQI moved -10 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 141, 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); Juneau (85.1% good, AQI 21); Kenai Peninsula (100.0% good, AQI 8).
Air Quality Summary
Good Days
90.3%
159 of 176 monitored days
15.3pp vs 75% target
Max AQI Recorded
141
USG
Health Grade
Excellent
90th-pct AQI 48
Matanuska-Susitna County, Good days share 90.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Matanuska-Susitna 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 176 monitored days across EPA AQI categories.
Good
159
90%
Moderate
15
9%
USG
2
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 Matanuska-Susitna County.
- PM2.5 · 89 days · 50.6%
- PM10 · 87 days · 49.4%
Health Impact Assessment
Excellent
Matanuska-Susitna County's air quality is rated Excellent based on 90.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 90.3% of monitored days in 2025, with a median AQI of 7. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 89 of 176 monitored days.
5-Year Air Quality Trend
Air quality is improving in Matanuska-Susitna County. Best year: 2024 (331 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 317 | 41 | 1 | 0 | 17 | 103 |
| 2021 | 307 | 44 | 2 | 1 | 15 | 163 |
| 2022 | 301 | 40 | 0 | 0 | 12 | 89 |
| 2023 | 317 | 40 | 1 | 0 | 14 | 102 |
| 2024 | 331 | 28 | 0 | 0 | 15 | 95 |
| 2025 | 159 | 15 | 2 | 0 | 7 | 141 |
How does Matanuska-Susitna County compare?
How Matanuska-Susitna County compares
Good-day share better than US avg
Matanuska-Susitna County 90.3%
Aleutians East County, Alaska 95.0%
US average 76.5%
Median AQI better than US avg
Matanuska-Susitna County 7
Aleutians East County, Alaska 11
US average 38
Unhealthy days / yr about average
Matanuska-Susitna 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 Matanuska-Susitna County.
Carbon County, Wyoming
AQI 7 · 100.0% good
Keweenaw County, Michigan
AQI 7 · 100.0% good
North Slope County, Alaska
AQI 7 · 100.0% good
Wilson County, Texas
AQI 7 · 100.0% good
Catron County, New Mexico
AQI 8 · 100.0% good
Hopewell City County, Virginia
AQI 6 · 100.0% good
What Matanuska-Susitna 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 7 means for exposure. Health guidance
- See how Matanuska-Susitna County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Matanuska-Susitna County with its Alaska neighbours before drawing a conclusion about the region. All of Alaska
Based on 176 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 Matanuska-Susitna County, Alaska? ▼
Matanuska-Susitna County has a median Air Quality Index (AQI) of 7, rated "Good." 90.3% of monitored days (159 out of 176) had good air quality in 2025.
What is the main pollutant in Matanuska-Susitna County? ▼
The primary pollutant in Matanuska-Susitna County is Fine Particles (PM2.5), which was the main AQI driver on 89 days (51% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Matanuska-Susitna County have? ▼
In 2025, Matanuska-Susitna County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 141.
Is the air quality in Matanuska-Susitna County getting better or worse? ▼
Air quality in Matanuska-Susitna County is improving based on 5-year trends (2020-2025). Best year: 2024 with 331 good days. Worst year: 2025 with 159 good days.
What does AQI 7 mean for health? ▼
Matanuska-Susitna County's median AQI of 7 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 Matanuska-Susitna County compare to other counties in Alaska? ▼
Matanuska-Susitna County has 90.3% 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), Juneau (85.1% good), Kenai Peninsula (100.0% good).
What is the 90th percentile AQI in Matanuska-Susitna County? ▼
The 90th percentile AQI for Matanuska-Susitna County is 48, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 141 (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.