Median AQI
26
Good
Oregon · County air quality · 2025
Harney County, Oregon
Median AQI 26 (Good). 70.7% of monitored days rated Good, direct from EPA Air Quality System stations.
- 26
- Median AQI
- 70.7%
- Good-air days
- 0
- Unhealthy days
- 32%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Harney County's air is good on balance, more polluted than the median US county, a median AQI of 26 with 70.7% of 181 monitored days in the Good band, driven mainly by PM2.5.
- 26
- median AQI · Good
- 70.7%
- days rated Good
- PM2.5
- main pollutant
- 32%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 93.
Data updated July 2026
- Good · 128 d · 70.7%
- Moderate · 53 d · 29.3%
How did Harney County's air break down in 2025?
Across 181 monitored days, 128 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 93 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 26 (Good).
Insights: Harney County, Oregon. EPA monitors recorded a median Air Quality Index of 26 across 181 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 128 (71%) fell in the Good band (AQI 0–50), 53 (29%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 60, while the worst single-day peak hit 93 (Moderate). Residents averaged about 21.2 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 -83 and the median AQI moved -16 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 93, 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
70.7%
128 of 181 monitored days
-4.3pp vs 75% target
Max AQI Recorded
93
Moderate
Health Grade
Moderate
90th-pct AQI 60
Harney County, Good days share 70.7%
National avg
Share of monitored days at AQI 0-50 (Good band).
Harney 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
128
71%
Moderate
53
29%
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 Harney County.
- PM2.5 · 181 days · 100.0%
Health Impact Assessment
Moderate
Harney County's air quality is rated Moderate based on 70.7% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 70.7% of monitored days in 2025, with a median AQI of 26. 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 Harney County. Best year: 2022 (226 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 211 | 144 | 2 | 7 | 42 | 357 |
| 2021 | 191 | 165 | 5 | 4 | 48 | 185 |
| 2022 | 226 | 137 | 2 | 0 | 41 | 114 |
| 2023 | 214 | 150 | 1 | 0 | 43 | 117 |
| 2024 | 200 | 139 | 6 | 16 | 46 | 271 |
| 2025 | 128 | 53 | 0 | 0 | 26 | 93 |
How does Harney County compare?
How Harney County compares
Good-day share worse than US avg
Harney County 70.7%
Baker County, Oregon 89.0%
US average 76.5%
Median AQI better than US avg
Harney County 26
Baker County, Oregon 25
US average 38
Unhealthy days / yr about average
Harney 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 Harney County.
Clallam County, Washington
AQI 26 · 88.5% good
Ford County, Kansas
AQI 26 · 89.4% good
Grant County, Washington
AQI 26 · 89.7% good
Taney County, Missouri
AQI 26 · 100.0% good
Thurston County, Washington
AQI 26 · 98.1% good
Wyoming County, Pennsylvania
AQI 26 · 83.1% good
What Harney 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 26 means for exposure. Health guidance
- See how Harney County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Harney 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 Harney County, Oregon? ▼
Harney County has a median Air Quality Index (AQI) of 26, rated "Good." 70.7% of monitored days (128 out of 181) had good air quality in 2025.
What is the main pollutant in Harney County? ▼
The primary pollutant in Harney 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 Harney County have? ▼
In 2025, Harney County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 93.
Is the air quality in Harney County getting better or worse? ▼
Air quality in Harney County is improving based on 5-year trends (2020-2025). Best year: 2022 with 226 good days. Worst year: 2025 with 128 good days.
What does AQI 26 mean for health? ▼
Harney County's median AQI of 26 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 Harney County compare to other counties in Oregon? ▼
Harney County has 70.7% 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 Harney County? ▼
The 90th percentile AQI for Harney County is 60, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 93 (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.