New Haven Air Quality in Summer
Across 2019–2025, New Haven's summer (June–August) air quality had a median AQI of 52 (Moderate) over 644 monitored days in the New Haven-Milford, CT area. 12.1% of summer days (78 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 62.4% of days. The cleanest summer on record here was 2022 (median AQI 49, 7 days above 100) and the worst was 2021 (median 52, 14 days above 100, peak AQI 159).
- Good: 42.5%
- Moderate: 45.3%
- Unhealthy for Sensitive Groups: 10.2%
- Unhealthy or worse: 1.9%
Reduce Indoor Ozone in New Haven
Today's main pollutant in New Haven is ground-level ozone (AQI 32). 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
As an Amazon Associate, we earn from qualifying purchases.
How is the air in New Haven in summer?
Moderate on a typical day: median AQI 52 across 2019–2025, with 12.1% of summer days above AQI 100. Ground-level ozone is the main driver.
- ✓42.5% of summer days were Good (AQI 0–50), 45.3% Moderate (51–100).
- ✓78 days of 644 reached AQI 101+; the summer peak was 208.
- ✓Cleanest month: August; worst month: July.
Frequently asked questions
What is the air quality like in New Haven in summer?▾
Across 2019–2025, the median daily AQI in New Haven in summer was 52 (Moderate). 42.5% of days were Good, 45.3% Moderate, and 12.1% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is summer a good time for outdoor exercise in New Haven?▾
A typical summer day in New Haven is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 8 of summer days (12.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes New Haven's summer air quality problems?▾
Ground-level ozone set the daily AQI on 62.4% of summer days in New Haven. The highest summer AQI recorded in 2019–2025 was 208 (Very Unhealthy), in 2021.
New Haven summer air quality, year by year
New Haven summer air quality by year (New Haven-Milford, CT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 54 | 12 | 159 | O3 |
| 2020 | 92 | 55 | 13 | 174 | O3 |
| 2021worst | 92 | 52 | 14 | 159 | PM2.5 |
| 2022cleanest | 92 | 49 | 7 | 133 | O3 |
| 2023 | 92 | 55 | 8 | 208 | O3 |
| 2024 | 92 | 51 | 11 | 156 | O3 |
| 2025 | 92 | 58 | 13 | 159 | O3 |
What summer air means in New Haven
A typical summer day in New Haven is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 8 of summer days (12.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Summer's median AQI of 52 is above New Haven's whole-year median of 44, making it one of the area's dirtier periods. Nationally, the median Summer AQI across every EPA metro area (308,645 metro-days, 2019–2025) is 46, so New Haven runs above the national Summer norm; 12.1% of its Summer days topped AQI 100 versus 3.6% nationally (above average).
Within the season, August is the cleanest month (median AQI 52, 10.6% of days above 100) and July the worst (median 57, 14.3% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in New Haven
The latest EPA AirNow observation puts New Haven's AQI at 32 (O3). The figures above are multi-year season 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.