Metro area air quality · 2025
Hermiston-Pendleton, OR
Median AQI 41 (Good). 71.2% of monitored days rated Good across this metro's EPA monitoring network.
- 41
- Median AQI
- 71.2%
- Good-air days
- 0
- Unhealthy days
- 48%
- Cleaner than US metros
Hermiston-Pendleton, OR posted a 2025 median AQI of 41 (Good) with 71.2% Good days
According to the U.S. EPA Air Quality System, the Hermiston-Pendleton, OR CBSA recorded a median AQI of 41 across 365 monitored days in 2025, with 71.2% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The Hermiston-Pendleton, OR CBSA's 71.2% Good-day share places it cleaner than 48% of US metros in 2025.
- Closest median-AQI peer
- Adrian, MI (69.3% Good, median AQI 41) is the closest nationwide median-AQI peer to Hermiston-Pendleton, OR.
- 2020–2025 Good-day shift
- Hermiston-Pendleton, OR's Good-day share moved -4.8 points from 2020 to 2025 (median AQI +3).
- Median AQI
- Median AQI: 41
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Hermiston-Pendleton, OR's peak reading 95 stays in the lower max-AQI tercile on this extract. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 41 and 71.2% of 365 monitored days in the Good band.
- 41
- median AQI · Good
- 71.2%
- days rated Good
- 48%
- cleaner than US metros
- 95
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Hermiston-Pendleton, OR metro's Good-day share fell from 75.1% to 71.2% between the 2024 and 2025 EPA annual releases, a change of -3.9 percentage points.
- Hermiston-Pendleton, OR metro's peak single-day AQI fell from 117 to 95 between the 2024 and 2025 EPA annual releases, a change of -22 points.
- Hermiston-Pendleton, OR metro's median AQI rose from 38 to 41 between the 2024 and 2025 EPA annual releases, a change of +3 points.
Hermiston-Pendleton, OR's peak reading 95 stays in the lower max-AQI tercile on this extract. Signature read: peak AQI 95 (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 41 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 260 Good (71%), 105 Moderate (29%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 64; the highest single-day reading hit 95 (Moderate).
Across 2020–2025, Good-day share shifted -4.8 points and median AQI moved +3 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Adrian, MI (69.3% good, AQI 41); Albany-Schenectady-Troy, NY (67.7% good, AQI 41); Ann Arbor, MI (69.3% good, AQI 41).
Air Quality Summary
Median AQI
41
Good
Good Days
71.2%
260 of 365 days
Max AQI
95
Moderate
Health Grade
Moderate
90th pct: 64
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
260
71%
Moderate
105
29%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Hermiston-Pendleton, OR metro area's air quality is rated Moderate based on 71.2% good air days. No unhealthy air days were recorded in 2025.
Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.
How does the Hermiston-Pendleton, OR metro compare?
How Hermiston-Pendleton, OR compares
5-Year Air Quality Trend
Air quality is worsening in the Hermiston-Pendleton, OR metro. Highest Good-day share: 2020 (76.0%, 273 of 359 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 273 | 85 | 1 | 38 | 738 |
| 2021 | 265 | 92 | 2 | 38 | 169 |
| 2022 | 244 | 118 | 0 | 39 | 141 |
| 2023 | 259 | 103 | 1 | 42 | 267 |
| 2024 | 272 | 90 | 0 | 38 | 117 |
| 2025 | 260 | 105 | 0 | 41 | 95 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Hermiston-Pendleton, OR (41).
Adrian, MI
Median AQI 41 · 69.3% Good-day share
Albany-Schenectady-Troy, NY
Median AQI 41 · 67.7% Good-day share
Ann Arbor, MI
Median AQI 41 · 69.3% Good-day share
Bowling Green, KY
Median AQI 41 · 75.6% Good-day share
Brunswick, GA
Median AQI 41 · 74.3% Good-day share
Decatur, AL
Median AQI 41 · 78.4% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Hermiston-Pendleton, OR's 0 (independent of median AQI).
Aberdeen, SD
0 unhealthy-or-worse days · median AQI 27
Aberdeen, WA
0 unhealthy-or-worse days · median AQI 22
Akron, OH
0 unhealthy-or-worse days · median AQI 45
Albany, GA
0 unhealthy-or-worse days · median AQI 46
Albany, OR
0 unhealthy-or-worse days · median AQI 27
Alexandria, LA
0 unhealthy-or-worse days · median AQI 37
Frequently Asked Questions
What is the 90th percentile AQI for Hermiston-Pendleton, OR? ▼
How many unhealthy air days does Hermiston-Pendleton, OR have? ▼
What is the air quality in the Hermiston-Pendleton, OR metro area? ▼
Is air quality in Hermiston-Pendleton, OR getting better or worse? ▼
What does AQI 41 mean for health? ▼
How does Hermiston-Pendleton, OR compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Hermiston-Pendleton, OR, 2025. See our methodology for how AQI, median, and coverage figures are computed.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, Hermiston-Pendleton, OR · 2020–2025