Cambridge Air Quality in November
Across 2019–2025, Cambridge's November air quality had a median AQI of 42 (Good) over 210 monitored days in the Boston-Cambridge-Newton, MA-NH area. 1.4% of November days (3 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 72.4% of days. The cleanest November on record here was 2023 (median AQI 35, 0 days above 100) and the worst was 2024 (median 43, 3 days above 100, peak AQI 1513).
- Good: 64.8%
- Moderate: 33.8%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 1.4%
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 November?
Good on a typical day: median AQI 42 across 2019–2025, with 1.4% of November days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓64.8% of November days were Good (AQI 0–50), 33.8% Moderate (51–100).
- ✓3 days of 210 reached AQI 101+; the November peak was 1513.
- ✓Best November: 2023; worst November: 2024.
Frequently asked questions
What is the air quality like in Cambridge in November?▾
Across 2019–2025, the median daily AQI in Cambridge in November was 42 (Good). 64.8% of days were Good, 33.8% Moderate, and 1.4% 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 Cambridge?▾
A typical November day in Cambridge sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 71 of November days (1.4%) reached AQI 101+ in 2019–2025.
Which pollutant causes Cambridge's November air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 72.4% of November days in Cambridge. The highest November AQI recorded in 2019–2025 was 1513 (Hazardous), in 2024.
Cambridge November air quality, year by year
Cambridge November 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 |
|---|---|---|---|---|---|
| 2019 | 30 | 52 | 0 | 69 | PM2.5 |
| 2020 | 30 | 48 | 0 | 82 | PM2.5 |
| 2021 | 30 | 44 | 0 | 70 | PM2.5 |
| 2022 | 30 | 40 | 0 | 60 | PM2.5 |
| 2023cleanest | 30 | 35 | 0 | 60 | PM2.5 |
| 2024worst | 30 | 43 | 3 | 1513 | PM2.5 |
| 2025 | 30 | 36 | 0 | 68 | PM2.5 |
What November air means in Cambridge
A typical November day in Cambridge sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 71 of November days (1.4%) reached AQI 101+ in 2019–2025.
November's median AQI of 42 is below Cambridge's whole-year median of 48, 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 Cambridge runs in line with the national November norm; 1.4% of its November days topped AQI 100 versus 0.6% nationally (about the same).
November is part of Cambridge's fall season (September, October, November); the fall 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.