Portland, ME Air Quality in 2022
In 2022, Portland's air quality (Portland-South Portland, ME area) had a median daily AQI of 37 (Good) across 362 monitored days. 3 days (0.8%) reached Unhealthy for Sensitive Groups or worse, 320 were Good, and the year's peak AQI was 126 (Unhealthy for Sensitive Groups). Ground-level ozone set the daily AQI on 287 of those days. The cleanest month of 2022 was October (median AQI 29, 0 days above 100) and the worst was July (median 44, 2 days above 100, peak 126).
- Good: 88.4%
- Moderate: 10.8%
- Unhealthy for Sensitive Groups: 0.8%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Portland
Today's main pollutant in Portland is ground-level ozone (AQI 27). 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 was Portland's air quality in 2022?
Good on a typical day: median AQI 37, with 3 days above AQI 100 out of 362 monitored — the 5th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2022: 126 (Unhealthy for Sensitive Groups).
- ✓Ground-level ozone was the main pollutant on 287 days.
- ✓Cleanest month: October; worst: July.
Frequently asked questions
What was the average AQI in Portland in 2022?▾
EPA's Air Quality System puts Portland's (Portland-South Portland, ME) median daily AQI for 2022 at 37, which is Good. 3 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 126.
Which month had the worst air quality in Portland in 2022?▾
The cleanest month of 2022 was October (median AQI 29, 0 days above 100) and the worst was July (median 44, 2 days above 100, peak 126).
Was 2022 a good or bad year for Portland's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2022 ranks 5th cleanest by days above AQI 100. 2022's median of 37 is below the area's typical annual median of 40.
Portland month by month in 2022
Portland air quality month by month, 2022 (Portland-South Portland, ME, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 41 | 0 | 62 | PM2.5 |
| February | 28 | 39 | 1 | 109 | O3 |
| March | 31 | 42 | 0 | 58 | O3 |
| April | 30 | 40 | 0 | 64 | O3 |
| May | 31 | 39 | 0 | 58 | O3 |
| June | 30 | 33 | 0 | 77 | O3 |
| Julyworst | 31 | 44 | 2 | 126 | O3 |
| August | 31 | 36 | 0 | 80 | O3 |
| September | 30 | 30 | 0 | 48 | O3 |
| Octobercleanest | 31 | 29 | 0 | 67 | O3 |
| November | 30 | 32 | 0 | 55 | O3 |
| December | 28 | 31 | 0 | 73 | O3 |
How 2022 compares
Among the 7 years EPA has published for the area (2019–2025), 2022 ranks 5th cleanest by days above AQI 100.
2022's median of 37 is below the area's typical annual median of 40.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Portland
The latest EPA AirNow observation puts Portland's AQI at 27 (O3). 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-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.