Median AQI
24
Good
Oregon · County air quality · 2025
Linn County, Oregon
Median AQI 24 (Good). 84.5% of monitored days rated Good, direct from EPA Air Quality System stations.
- 24
- Median AQI
- 84.5%
- Good-air days
- 0
- Unhealthy days
- 64%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Linn County's air is good on balance, cleaner than the median US county, a median AQI of 24 with 84.5% of 181 monitored days in the Good band, driven mainly by PM2.5.
- 24
- median AQI · Good
- 84.5%
- days rated Good
- PM2.5
- main pollutant
- 64%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 89.
Data updated July 2026
- Good · 153 d · 84.5%
- Moderate · 28 d · 15.5%
How did Linn County's air break down in 2025?
Across 181 monitored days, 153 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 89 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 24 (Good).
Insights: Linn County, Oregon. EPA monitors recorded a median Air Quality Index of 24 across 181 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 153 (85%) fell in the Good band (AQI 0–50), 28 (15%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 56, while the worst single-day peak hit 89 (Moderate). Residents averaged about 25.4 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 -92 and the median AQI moved -12 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 89, moderate but never Unhealthy. Nearby counties show comparable readings: Baker (89.0% good, AQI 25); Clackamas (93.9% good, AQI 27); Columbia (96.7% good, AQI 25); Crook (80.7% good, AQI 24); Deschutes (93.4% good, AQI 22); Grant (66.7% good, AQI 34).
Air Quality Summary
Good Days
84.5%
153 of 181 monitored days
9.5pp vs 75% target
Max AQI Recorded
89
Moderate
Health Grade
Good
90th-pct AQI 56
Linn County, Good days share 84.5%
National avg
Share of monitored days at AQI 0-50 (Good band).
Linn 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
153
85%
Moderate
28
15%
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 Linn County.
- PM2.5 · 181 days · 100.0%
Health Impact Assessment
Good
Linn County's air quality is rated Good based on 84.5% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 84.5% of monitored days in 2025, with a median AQI of 24. 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 improving in Linn County. Best year: 2024 (320 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 245 | 110 | 0 | 0 | 36 | 853 |
| 2021 | 268 | 96 | 1 | 0 | 34 | 136 |
| 2022 | 254 | 109 | 2 | 0 | 33 | 127 |
| 2023 | 278 | 83 | 4 | 0 | 34 | 125 |
| 2024 | 320 | 46 | 0 | 0 | 25 | 86 |
| 2025 | 153 | 28 | 0 | 0 | 24 | 89 |
How does Linn County compare?
How Linn County compares
Good-day share better than US avg
Linn County 84.5%
Baker County, Oregon 89.0%
US average 76.5%
Median AQI better than US avg
Linn County 24
Baker County, Oregon 25
US average 38
Unhealthy days / yr about average
Linn County 0
Baker County, Oregon 0
US average 0
Other Counties in Oregon
Air quality comparison for nearby counties in Oregon.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Linn County.
Alamosa County, Colorado
AQI 24 · 90.8% good
Anchorage County, Alaska
AQI 24 · 80.8% good
Charlton County, Georgia
AQI 24 · 79.0% good
Crook County, Oregon
AQI 24 · 80.7% good
Culberson County, Texas
AQI 24 · 80.0% good
Kootenai County, Idaho
AQI 24 · 88.4% good
What Linn 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 24 means for exposure. Health guidance
- See how Linn County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Linn County with its Oregon neighbours before drawing a conclusion about the region. All of Oregon
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 Linn County, Oregon? ▼
Linn County has a median Air Quality Index (AQI) of 24, rated "Good." 84.5% of monitored days (153 out of 181) had good air quality in 2025.
What is the main pollutant in Linn County? ▼
The primary pollutant in Linn 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 Linn County have? ▼
In 2025, Linn County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 89.
Is the air quality in Linn County getting better or worse? ▼
Air quality in Linn County is improving based on 5-year trends (2020-2025). Best year: 2024 with 320 good days. Worst year: 2025 with 153 good days.
What does AQI 24 mean for health? ▼
Linn County's median AQI of 24 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 Linn County compare to other counties in Oregon? ▼
Linn County has 84.5% good air days. Nearby counties in Oregon: Baker (89.0% good), Clackamas (93.9% good), Columbia (96.7% good), Crook (80.7% good), Deschutes (93.4% good), Grant (66.7% good).
What is the 90th percentile AQI in Linn County? ▼
The 90th percentile AQI for Linn County is 56, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 89 (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.