Portland, OR Air Quality in Spring
Across 2019–2025, Portland's spring (March–May) air quality had a median AQI of 39 (Good) over 644 monitored days in the Portland-Vancouver-Hillsboro, OR-WA area. 0.2% of spring days (1 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 65.1% of days. The cleanest spring on record here was 2022 (median AQI 36, 0 days above 100) and the worst was 2020 (median 39, 1 day above 100, peak AQI 112).
- Good: 84.2%
- Moderate: 15.7%
- Unhealthy for Sensitive Groups: 0.2%
- Unhealthy or worse: 0.0%
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How is the air in Portland in spring?
Good on a typical day: median AQI 39 across 2019–2025, with 0.2% of spring days above AQI 100. Ground-level ozone is the main driver.
- ✓84.2% of spring days were Good (AQI 0–50), 15.7% Moderate (51–100).
- ✓1 day of 644 reached AQI 101+; the spring peak was 112.
- ✓Cleanest month: April; worst month: May.
Frequently asked questions
What is the air quality like in Portland in spring?▾
Across 2019–2025, the median daily AQI in Portland in spring was 39 (Good). 84.2% of days were Good, 15.7% Moderate, and 0.2% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is spring a good time for outdoor exercise in Portland?▾
A typical spring day in Portland sits in the Good range (median AQI 39), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of spring days reached AQI 101+ in 2019–2025.
Which pollutant causes Portland's spring air quality problems?▾
Ground-level ozone set the daily AQI on 65.1% of spring days in Portland. The highest spring AQI recorded in 2019–2025 was 112 (Unhealthy for Sensitive Groups), in 2020.
Portland spring air quality, year by year
Portland spring air quality by year (Portland-Vancouver-Hillsboro, OR-WA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 41 | 0 | 84 | O3 |
| 2020worst | 92 | 39 | 1 | 112 | O3 |
| 2021 | 92 | 43 | 0 | 94 | O3 |
| 2022cleanest | 92 | 36 | 0 | 73 | O3 |
| 2023 | 92 | 39 | 0 | 69 | O3 |
| 2024 | 92 | 38 | 0 | 61 | O3 |
| 2025 | 92 | 39 | 0 | 71 | O3 |
What spring air means in Portland
A typical spring day in Portland sits in the Good range (median AQI 39), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of spring days reached AQI 101+ in 2019–2025.
Spring's median AQI of 39 is in line with Portland's whole-year median of 41, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so Portland runs below the national Spring norm; 0.2% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).
Within the season, April is the cleanest month (median AQI 38, 0.0% of days above 100) and May the worst (median 39, 0.5% above 100).
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 season 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.