Portland, ME Air Quality in June
Across 2019–2025, Portland's June air quality had a median AQI of 44 (Good) over 210 monitored days in the Portland-South Portland, ME area. 2.4% of June days (5 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 50.0% of days. The cleanest June on record here was 2022 (median AQI 33, 0 days above 100) and the worst was 2021 (median 46, 2 days above 100, peak AQI 129).
- Good: 59.5%
- Moderate: 38.1%
- Unhealthy for Sensitive Groups: 2.4%
- 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
As an Amazon Associate, we earn from qualifying purchases.
How is the air in Portland in June?
Good on a typical day: median AQI 44 across 2019–2025, with 2.4% of June days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓59.5% of June days were Good (AQI 0–50), 38.1% Moderate (51–100).
- ✓5 days of 210 reached AQI 101+; the June peak was 147.
- ✓Best June: 2022; worst June: 2021.
Frequently asked questions
What is the air quality like in Portland in June?▾
Across 2019–2025, the median daily AQI in Portland in June was 44 (Good). 59.5% of days were Good, 38.1% Moderate, and 2.4% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is June a good time for outdoor exercise in Portland?▾
A typical June day in Portland sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 42 of June days (2.4%) reached AQI 101+ in 2019–2025.
Which pollutant causes Portland's June air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 50.0% of June days in Portland. The highest June AQI recorded in 2019–2025 was 147 (Unhealthy for Sensitive Groups), in 2021.
Portland June air quality, year by year
Portland June air quality by year (Portland-South Portland, ME, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 51 | 0 | 58 | PM2.5 |
| 2020 | 30 | 53 | 0 | 77 | PM2.5 |
| 2021worst | 30 | 46 | 2 | 129 | O3 |
| 2022cleanest | 30 | 33 | 0 | 77 | O3 |
| 2023 | 30 | 47 | 0 | 77 | PM2.5 |
| 2024 | 30 | 43 | 1 | 129 | O3 |
| 2025 | 30 | 42 | 2 | 147 | PM2.5 |
What June air means in Portland
A typical June day in Portland sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 42 of June days (2.4%) reached AQI 101+ in 2019–2025.
June's median AQI of 44 is above Portland's whole-year median of 40, making it one of the area's dirtier periods. Nationally, the median June AQI across every EPA metro area (100,635 metro-days, 2019–2025) is 46, so Portland runs in line with the national June norm; 2.4% of its June days topped AQI 100 versus 3.7% nationally (below average).
June is part of Portland's summer season (June, July, August); the summer 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.