Metro area air quality · 2025
Portland-Vancouver-Hillsboro, OR-WA
Median AQI 41 (Good). 69.9% of monitored days rated Good across this metro's EPA monitoring network.
- 41
- Median AQI
- 69.9%
- Good-air days
- 0
- Unhealthy days
- 45%
- Cleaner than US metros
Portland-Vancouver-Hillsboro, OR-WA posted a 2025 median AQI of 41 (Good) with 69.9% Good days
According to the U.S. EPA Air Quality System, the Portland-Vancouver-Hillsboro, OR-WA CBSA recorded a median AQI of 41 across 365 monitored days in 2025, with 69.9% 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 Portland-Vancouver-Hillsboro, OR-WA CBSA's 69.9% Good-day share places it cleaner than 45% 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 Portland-Vancouver-Hillsboro, OR-WA.
- 2020–2025 Good-day shift
- Portland-Vancouver-Hillsboro, OR-WA's Good-day share moved +1.2 points from 2020 to 2025 (median AQI +0).
- Median AQI
- Median AQI: 41
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Portland-Vancouver-Hillsboro, OR-WA's Good-day share (69.9%) sits in the middle CBSA 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 69.9% of 365 monitored days in the Good band.
- 41
- median AQI · Good
- 69.9%
- days rated Good
- 45%
- cleaner than US metros
- 119
- 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
- Portland-Vancouver-Hillsboro, OR-WA metro's Good-day share fell from 77.8% to 70.2% between the 2024 and 2025 EPA annual releases, a change of -7.5 percentage points.
- Portland-Vancouver-Hillsboro, OR-WA metro's median AQI rose from 38 to 41 between the 2024 and 2025 EPA annual releases, a change of +3 points.
Portland-Vancouver-Hillsboro, OR-WA's Good-day share (69.9%) sits in the middle CBSA tercile on this extract. Signature read: 69.9% Good-day share (mid 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 255 Good (70%), 108 Moderate (30%), and 2 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 63; the highest single-day reading hit 119 (USG).
Across 2020–2025, Good-day share shifted +1.2 points and median AQI moved +0 (stable). 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
69.9%
255 of 365 days
Max AQI
119
USG
Health Grade
Moderate
90th pct: 63
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
255
70%
Moderate
108
30%
USG
2
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Portland-Vancouver-Hillsboro, OR-WA metro area's air quality is rated Moderate based on 69.9% 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 Portland-Vancouver-Hillsboro, OR-WA metro compare?
How Portland-Vancouver-Hillsboro, OR-WA compares
5-Year Air Quality Trend
Air quality is stable in the Portland-Vancouver-Hillsboro, OR-WA metro. Highest Good-day share: 2024 (77.8%, 280 of 360 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 243 | 109 | 0 | 41 | 874 |
| 2021 | 254 | 110 | 1 | 42 | 161 |
| 2022 | 225 | 133 | 4 | 41 | 175 |
| 2023 | 219 | 140 | 2 | 43 | 153 |
| 2024 | 280 | 80 | 0 | 38 | 127 |
| 2025 | 255 | 108 | 0 | 41 | 119 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Portland-Vancouver-Hillsboro, OR-WA (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 Portland-Vancouver-Hillsboro, OR-WA'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
How many unhealthy air days does Portland-Vancouver-Hillsboro, OR-WA have? ▼
What is the air quality in the Portland-Vancouver-Hillsboro, OR-WA metro area? ▼
Is air quality in Portland-Vancouver-Hillsboro, OR-WA getting better or worse? ▼
What does AQI 41 mean for health? ▼
How does Portland-Vancouver-Hillsboro, OR-WA compare to other metro areas? ▼
What is the 90th percentile AQI for Portland-Vancouver-Hillsboro, OR-WA? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Portland-Vancouver-Hillsboro, OR-WA, 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, Portland-Vancouver-Hillsboro, OR-WA · 2020–2025