Portland, ME Air Quality in November
Across 2019–2025, Portland's November air quality had a median AQI of 33 (Good) over 210 monitored days in the Portland-South Portland, ME area. 0.0% of November days (0 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 58.1% of days. The cleanest November on record here was 2021 (median AQI 31, 0 days above 100) and the worst was 2019 (median 39, 0 days above 100, peak AQI 69).
- Good: 86.2%
- Moderate: 13.8%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Portland
Today's main pollutant in Portland is ground-level ozone (AQI 29). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Portland in November?
Good on a typical day: median AQI 33 across 2019–2025, with 0.0% of November days above AQI 100. Ground-level ozone is the main driver.
- ✓86.2% of November days were Good (AQI 0–50), 13.8% Moderate (51–100).
- ✓0 days of 210 reached AQI 101+; the November peak was 97.
- ✓Best November: 2021; worst November: 2019.
Frequently asked questions
What is the air quality like in Portland in November?▾
Across 2019–2025, the median daily AQI in Portland in November was 33 (Good). 86.2% of days were Good, 13.8% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is November a good time for outdoor exercise in Portland?▾
A typical November day in Portland sits in the Good range (median AQI 33), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of November days reached AQI 101+ in 2019–2025.
Which pollutant causes Portland's November air quality problems?▾
Ground-level ozone set the daily AQI on 58.1% of November days in Portland. The highest November AQI recorded in 2019–2025 was 97 (Moderate), in 2019.
Portland November air quality, year by year
Portland November air quality by year (Portland-South Portland, ME, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 30 | 39 | 0 | 69 | PM2.5 |
| 2020 | 30 | 33 | 0 | 97 | PM2.5 |
| 2021cleanest | 30 | 31 | 0 | 56 | O3 |
| 2022 | 30 | 32 | 0 | 55 | O3 |
| 2023 | 30 | 36 | 0 | 64 | PM2.5 |
| 2024 | 30 | 32 | 0 | 44 | O3 |
| 2025 | 30 | 31 | 0 | 57 | O3 |
What November air means in Portland
A typical November day in Portland sits in the Good range (median AQI 33), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of November days reached AQI 101+ in 2019–2025.
November's median AQI of 33 is below Portland's whole-year median of 40, making it one of the area's cleaner periods. Nationally, the median November AQI across every EPA metro area (92,704 metro-days, 2019–2025) is 39, so Portland runs below the national November norm; 0.0% of its November days topped AQI 100 versus 0.6% nationally (about the same).
November is part of Portland's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Portland
The latest EPA AirNow observation puts Portland's AQI at 29 (O3). The figures above are multi-year month 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-South Portland, ME), 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.