Portland, OR Air Quality in 2020
In 2020, Portland's air quality (Portland-Vancouver-Hillsboro, OR-WA area) had a median daily AQI of 41 (Good) across 366 monitored days. 14 days (3.8%) reached Unhealthy for Sensitive Groups or worse, 243 were Good, and the year's peak AQI was 874 (Hazardous). Fine particulate matter (PM2.5) set the daily AQI on 210 of those days. The cleanest month of 2020 was June (median AQI 30, 0 days above 100) and the worst was September (median 55, 11 days above 100, peak 874).
- Good: 66.4%
- Moderate: 29.8%
- Unhealthy for Sensitive Groups: 1.6%
- Unhealthy or worse: 2.2%
Improve Indoor Air Quality
Even with good outdoor air in Portland, indoor PM2.5, dust and allergens build up. A True-HEPA purifier keeps a bedroom or office consistently clean.
Recommended: Levoit Core 400S — True HEPA · CADR ~141 CFM · rooms up to 219 sq ft
As an Amazon Associate, we earn from qualifying purchases.
How was Portland's air quality in 2020?
Good on a typical day: median AQI 41, with 14 days above AQI 100 out of 366 monitored — the 7th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2020: 874 (Hazardous).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 210 days.
- ✓Cleanest month: June; worst: September.
Frequently asked questions
What was the average AQI in Portland in 2020?▾
EPA's Air Quality System puts Portland's (Portland-Vancouver-Hillsboro, OR-WA) median daily AQI for 2020 at 41, which is Good. 14 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 874.
Which month had the worst air quality in Portland in 2020?▾
The cleanest month of 2020 was June (median AQI 30, 0 days above 100) and the worst was September (median 55, 11 days above 100, peak 874).
Was 2020 a good or bad year for Portland's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 7th cleanest by days above AQI 100 — the worst year on record here. 2020's median of 41 is in line with the area's typical annual median of 41.
Portland month by month in 2020
Portland air quality month by month, 2020 (Portland-Vancouver-Hillsboro, OR-WA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 33 | 0 | 66 | O3 |
| February | 29 | 51 | 0 | 68 | PM2.5 |
| March | 31 | 43 | 0 | 76 | PM2.5 |
| April | 30 | 38 | 0 | 71 | O3 |
| May | 31 | 38 | 1 | 112 | O3 |
| Junecleanest | 30 | 30 | 0 | 54 | O3 |
| July | 31 | 37 | 1 | 119 | O3 |
| August | 31 | 37 | 1 | 122 | O3 |
| Septemberworst | 30 | 55 | 11 | 874 | PM2.5 |
| October | 31 | 55 | 0 | 82 | PM2.5 |
| November | 30 | 55 | 0 | 91 | PM2.5 |
| December | 31 | 56 | 0 | 92 | PM2.5 |
How 2020 compares
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 7th cleanest by days above AQI 100 — the worst year on record here.
2020'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 39 (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.