New Haven Air Quality in July
Across 2019–2025, New Haven's July air quality had a median AQI of 57 (Moderate) over 217 monitored days in the New Haven-Milford, CT area. 14.3% of July days (31 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 57.6% of days. The cleanest July on record here was 2024 (median AQI 50, 1 day above 100) and the worst was 2019 (median 67, 8 days above 100, peak AQI 159).
- Good: 34.6%
- Moderate: 51.2%
- Unhealthy for Sensitive Groups: 11.1%
- Unhealthy or worse: 3.2%
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
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How is the air in New Haven in July?
Moderate on a typical day: median AQI 57 across 2019–2025, with 14.3% of July days above AQI 100. Ground-level ozone is the main driver.
- ✓34.6% of July days were Good (AQI 0–50), 51.2% Moderate (51–100).
- ✓31 days of 217 reached AQI 101+; the July peak was 174.
- ✓Best July: 2024; worst July: 2019.
Frequently asked questions
What is the air quality like in New Haven in July?▾
Across 2019–2025, the median daily AQI in New Haven in July was 57 (Moderate). 34.6% of days were Good, 51.2% Moderate, and 14.3% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is July a good time for outdoor exercise in New Haven?▾
A typical July day in New Haven is Moderate (median AQI 57): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 7 of July days (14.3%) 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 July air quality problems?▾
Ground-level ozone set the daily AQI on 57.6% of July days in New Haven. The highest July AQI recorded in 2019–2025 was 174 (Unhealthy), in 2019.
New Haven July air quality, year by year
New Haven July air quality by year (New Haven-Milford, CT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 31 | 67 | 8 | 159 | O3 |
| 2020 | 31 | 55 | 8 | 174 | PM2.5 |
| 2021 | 31 | 54 | 4 | 159 | PM2.5 |
| 2022 | 31 | 54 | 2 | 126 | O3 |
| 2023 | 31 | 62 | 3 | 140 | O3 |
| 2024cleanest | 31 | 50 | 1 | 112 | O3 |
| 2025 | 31 | 58 | 5 | 159 | O3 |
What July air means in New Haven
A typical July day in New Haven is Moderate (median AQI 57): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 7 of July days (14.3%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
July's median AQI of 57 is above New Haven's whole-year median of 44, making it one of the area's dirtier periods. Nationally, the median July AQI across every EPA metro area (103,858 metro-days, 2019–2025) is 47, so New Haven runs above the national July norm; 14.3% of its July days topped AQI 100 versus 3.6% nationally (above average).
July is part of New Haven's summer season (June, July, August); the summer page pools all three months.
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 month 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.