Portland, OR Air Quality in 2025
In 2025, Portland's air quality (Portland-Vancouver-Hillsboro, OR-WA area) had a median daily AQI of 41 (Good) across 365 monitored days. 2 days (0.5%) reached Unhealthy for Sensitive Groups or worse, 255 were Good, and the year's peak AQI was 119 (Unhealthy for Sensitive Groups). Ground-level ozone set the daily AQI on 192 of those days. The cleanest month of 2025 was March (median AQI 36, 0 days above 100) and the worst was August (median 44, 2 days above 100, peak 119).
- Good: 69.9%
- Moderate: 29.6%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
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How was Portland's air quality in 2025?
Good on a typical day: median AQI 41, with 2 days above AQI 100 out of 365 monitored — the 2nd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2025: 119 (Unhealthy for Sensitive Groups).
- ✓Ground-level ozone was the main pollutant on 192 days.
- ✓Cleanest month: March; worst: August.
Frequently asked questions
What was the average AQI in Portland in 2025?▾
EPA's Air Quality System puts Portland's (Portland-Vancouver-Hillsboro, OR-WA) median daily AQI for 2025 at 41, which is Good. 2 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 119.
Which month had the worst air quality in Portland in 2025?▾
The cleanest month of 2025 was March (median AQI 36, 0 days above 100) and the worst was August (median 44, 2 days above 100, peak 119).
Was 2025 a good or bad year for Portland's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 2nd cleanest by days above AQI 100. 2025's median of 41 is in line with the area's typical annual median of 41.
Portland month by month in 2025
Portland air quality month by month, 2025 (Portland-Vancouver-Hillsboro, OR-WA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 56 | 0 | 88 | PM2.5 |
| February | 28 | 38 | 0 | 66 | PM2.5 |
| Marchcleanest | 31 | 36 | 0 | 61 | O3 |
| April | 30 | 39 | 0 | 51 | O3 |
| May | 31 | 42 | 0 | 71 | O3 |
| June | 30 | 40 | 0 | 90 | O3 |
| July | 31 | 39 | 0 | 61 | O3 |
| Augustworst | 31 | 44 | 2 | 119 | O3 |
| September | 30 | 46 | 0 | 68 | PM2.5 |
| October | 31 | 46 | 0 | 73 | PM2.5 |
| November | 30 | 53 | 0 | 78 | PM2.5 |
| December | 31 | 44 | 0 | 83 | PM2.5 |
How 2025 compares
Among the 7 years EPA has published for the area (2019–2025), 2025 ranks 2nd cleanest by days above AQI 100.
2025's median of 41 is in line with the area's typical annual median of 41.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Portland
The latest EPA AirNow observation puts Portland's AQI at 29 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Portland air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Portland-Vancouver-Hillsboro, OR-WA), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.