Boston Air Quality in June
Across 2019–2025, Boston's June air quality had a median AQI of 51 (Moderate) over 210 monitored days in the Boston-Cambridge-Newton, MA-NH area. 3.8% of June days (8 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 56.2% of days. The cleanest June on record here was 2019 (median AQI 46, 0 days above 100) and the worst was 2023 (median 59, 3 days above 100, peak AQI 136).
- Good: 49.0%
- Moderate: 47.1%
- Unhealthy for Sensitive Groups: 3.8%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Boston
Today's main pollutant in Boston is ground-level ozone (AQI 33). 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 Boston in June?
Moderate on a typical day: median AQI 51 across 2019–2025, with 3.8% of June days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓49.0% of June days were Good (AQI 0–50), 47.1% Moderate (51–100).
- ✓8 days of 210 reached AQI 101+; the June peak was 136.
- ✓Best June: 2019; worst June: 2023.
Frequently asked questions
What is the air quality like in Boston in June?▾
Across 2019–2025, the median daily AQI in Boston in June was 51 (Moderate). 49.0% of days were Good, 47.1% Moderate, and 3.8% 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 Boston?▾
A typical June day in Boston is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 26 of June days (3.8%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Boston's June air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 56.2% of June days in Boston. The highest June AQI recorded in 2019–2025 was 136 (Unhealthy for Sensitive Groups), in 2023.
Boston June air quality, year by year
Boston June air quality by year (Boston-Cambridge-Newton, MA-NH, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 30 | 46 | 0 | 84 | O3 |
| 2020 | 30 | 51 | 0 | 74 | PM2.5 |
| 2021 | 30 | 57 | 2 | 122 | PM2.5 |
| 2022 | 30 | 48 | 0 | 90 | PM2.5 |
| 2023worst | 30 | 59 | 3 | 136 | O3 |
| 2024 | 30 | 49 | 1 | 122 | O3 |
| 2025 | 30 | 55 | 2 | 133 | PM2.5 |
What June air means in Boston
A typical June day in Boston is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 26 of June days (3.8%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
June's median AQI of 51 is in line with Boston's whole-year median of 48, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median June AQI across every EPA metro area (100,635 metro-days, 2019–2025) is 46, so Boston runs above the national June norm; 3.8% of its June days topped AQI 100 versus 3.7% nationally (about the same).
June is part of Boston's summer season (June, July, August); the summer page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Boston
The latest EPA AirNow observation puts Boston's AQI at 33 (O3). The figures above are multi-year month statistics, not today's reading.
View current Boston air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Boston-Cambridge-Newton, MA-NH), 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.