New Haven Air Quality in 2020
In 2020, New Haven's air quality (New Haven-Milford, CT area) had a median daily AQI of 46 (Good) across 366 monitored days. 13 days (3.6%) reached Unhealthy for Sensitive Groups or worse, 210 were Good, and the year's peak AQI was 174 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 198 of those days. The cleanest month of 2020 was September (median AQI 38, 0 days above 100) and the worst was July (median 55, 8 days above 100, peak 174).
- Good: 57.4%
- Moderate: 39.1%
- Unhealthy for Sensitive Groups: 3.0%
- Unhealthy or worse: 0.5%
Reduce Indoor Ozone in New Haven
Today's main pollutant in New Haven is ground-level ozone (AQI 30). 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 was New Haven's air quality in 2020?
Good on a typical day: median AQI 46, with 13 days above AQI 100 out of 366 monitored — the 5th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2020: 174 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 198 days.
- ✓Cleanest month: September; worst: July.
Frequently asked questions
What was the average AQI in New Haven in 2020?▾
EPA's Air Quality System puts New Haven's (New Haven-Milford, CT) median daily AQI for 2020 at 46, which is Good. 13 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 174.
Which month had the worst air quality in New Haven in 2020?▾
The cleanest month of 2020 was September (median AQI 38, 0 days above 100) and the worst was July (median 55, 8 days above 100, peak 174).
Was 2020 a good or bad year for New Haven's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 5th cleanest by days above AQI 100. 2020's median of 46 is in line with the area's typical annual median of 44.
New Haven month by month in 2020
New Haven air quality month by month, 2020 (New Haven-Milford, CT, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 48 | 0 | 85 | PM2.5 |
| February | 29 | 51 | 0 | 71 | PM2.5 |
| March | 31 | 42 | 0 | 65 | O3 |
| April | 30 | 46 | 0 | 59 | O3 |
| May | 31 | 44 | 0 | 84 | O3 |
| June | 30 | 55 | 1 | 101 | O3 |
| Julyworst | 31 | 55 | 8 | 174 | PM2.5 |
| August | 31 | 54 | 4 | 150 | O3 |
| Septembercleanest | 30 | 38 | 0 | 77 | PM2.5 |
| October | 31 | 43 | 0 | 60 | PM2.5 |
| November | 30 | 52 | 0 | 98 | PM2.5 |
| December | 31 | 49 | 0 | 96 | PM2.5 |
How 2020 compares
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 5th cleanest by days above AQI 100.
2020's median of 46 is in line with the area's typical annual median of 44.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in New Haven
The latest EPA AirNow observation puts New Haven's AQI at 30 (O3). The figures above are multi-year annual statistics, not today's reading.
View current New Haven air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (New Haven-Milford, CT), 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.