Cambridge Air Quality in June
Across 2019–2025, Cambridge'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 Cambridge
Today's main pollutant in Cambridge 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.
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How is the air in Cambridge 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 Cambridge in June?▾
Across 2019–2025, the median daily AQI in Cambridge 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 Cambridge?▾
A typical June day in Cambridge 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 Cambridge's June air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 56.2% of June days in Cambridge. The highest June AQI recorded in 2019–2025 was 136 (Unhealthy for Sensitive Groups), in 2023.
Cambridge June air quality, year by year
Cambridge 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 Cambridge
A typical June day in Cambridge 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 Cambridge'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 Cambridge 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 Cambridge's summer season (June, July, August); the summer page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Cambridge
The latest EPA AirNow observation puts Cambridge's AQI at 33 (O3). The figures above are multi-year month statistics, not today's reading.
View current Cambridge 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.