Boston Air Quality in February
Across 2019–2025, Boston's February air quality had a median AQI of 50 (Good) over 198 monitored days in the Boston-Cambridge-Newton, MA-NH area. 0.0% of February days (0 of 198) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 71.7% of days. The cleanest February on record here was 2024 (median AQI 42, 0 days above 100) and the worst was 2023 (median 53, 0 days above 100, peak AQI 74).
- Good: 52.5%
- Moderate: 47.5%
- Unhealthy for Sensitive Groups: 0.0%
- 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.
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How is the air in Boston in February?
Good on a typical day: median AQI 50 across 2019–2025, with 0.0% of February days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓52.5% of February days were Good (AQI 0–50), 47.5% Moderate (51–100).
- ✓0 days of 198 reached AQI 101+; the February peak was 77.
- ✓Best February: 2024; worst February: 2023.
Frequently asked questions
What is the air quality like in Boston in February?▾
Across 2019–2025, the median daily AQI in Boston in February was 50 (Good). 52.5% of days were Good, 47.5% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 198 monitored days in EPA's Air Quality System.
Is February a good time for outdoor exercise in Boston?▾
A typical February day in Boston sits in the Good range (median AQI 50), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of February days reached AQI 101+ in 2019–2025.
Which pollutant causes Boston's February air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 71.7% of February days in Boston. The highest February AQI recorded in 2019–2025 was 77 (Moderate), in 2023.
Boston February air quality, year by year
Boston February 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 | 28 | 50 | 0 | 77 | PM2.5 |
| 2020 | 29 | 51 | 0 | 63 | PM2.5 |
| 2021 | 28 | 49 | 0 | 66 | PM2.5 |
| 2022 | 28 | 52 | 0 | 73 | PM2.5 |
| 2023worst | 28 | 53 | 0 | 74 | PM2.5 |
| 2024cleanest | 29 | 42 | 0 | 63 | O3 |
| 2025 | 28 | 43 | 0 | 61 | O3 |
What February air means in Boston
A typical February day in Boston sits in the Good range (median AQI 50), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of February days reached AQI 101+ in 2019–2025.
February's median AQI of 50 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 February AQI across every EPA metro area (87,428 metro-days, 2019–2025) is 41, so Boston runs above the national February norm; 0.0% of its February days topped AQI 100 versus 0.4% nationally (about the same).
February is part of Boston's winter season (December, January, February); the winter 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.