Metro area air quality · 2025
New Haven-Milford, CT
Median AQI 43 (Good). 67.1% of monitored days rated Good across this metro's EPA monitoring network.
- 43
- Median AQI
- 67.1%
- Good-air days
- 2
- Unhealthy days
- 39%
- Cleaner than US metros
New Haven-Milford, CT posted a 2025 median AQI of 43 (Good) with 67.1% Good days
According to the U.S. EPA Air Quality System, the New Haven-Milford, CT CBSA recorded a median AQI of 43 across 365 monitored days in 2025, with 67.1% rated Good and 2 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The New Haven-Milford, CT CBSA's 67.1% Good-day share places it cleaner than 39% of US metros in 2025.
- Closest median-AQI peer
- Ashtabula, OH (81.2% Good, median AQI 43) is the closest nationwide median-AQI peer to New Haven-Milford, CT.
- 2020–2025 Good-day shift
- New Haven-Milford, CT's Good-day share moved +10.1 points from 2020 to 2025 (median AQI -3).
- Median AQI
- Median AQI: 43
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
New Haven-Milford, CT's peak reading 159 is in the upper max-AQI tercile among CBSA metros here. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 43 and 67.1% of 365 monitored days in the Good band.
- 43
- median AQI · Good
- 67.1%
- days rated Good
- 39%
- cleaner than US metros
- 159
- worst single reading
2 days reached Unhealthy or worse across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- New Haven-Milford, CT metro's Good-day share fell from 73.2% to 69.2% between the 2024 and 2025 EPA annual releases, a change of -4.0 percentage points.
- New Haven-Milford, CT metro's Unhealthy-category days rose from 1 to 2 between the 2024 and 2025 EPA annual releases, a change of +1 days.
New Haven-Milford, CT's peak reading 159 is in the upper max-AQI tercile among CBSA metros here. Signature read: peak AQI 159 (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 43 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 245 Good (67%), 107 Moderate (29%), and 11 Unhealthy-for-Sensitive-Groups (3%). The 90th-percentile AQI finished at 68; the highest single-day reading hit 159 (Unhealthy).
Across 2020–2025, Good-day share shifted +10.1 points and median AQI moved -3 (improving). The annual record contains 2 days at Unhealthy or worse. Metros with comparable AQI profiles include Ashtabula, OH (81.2% good, AQI 43); Bloomington, IN (67.7% good, AQI 43); Champaign-Urbana, IL (65.8% good, AQI 43).
Air Quality Summary
Median AQI
43
Good
Good Days
67.1%
245 of 365 days
Max AQI
159
Unhealthy
Health Grade
Moderate
90th pct: 68
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
245
67%
Moderate
107
29%
USG
11
3%
Unhealthy
2
1%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The New Haven-Milford, CT metro area's air quality is rated Moderate based on 67.1% good air days. There were 2 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 11 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 159. Sensitive groups should monitor real-time conditions at AirNow.gov.
How does the New Haven-Milford, CT metro compare?
How New Haven-Milford, CT compares
5-Year Air Quality Trend
Air quality is improving in the New Haven-Milford, CT metro. Highest Good-day share: 2024 (73.2%, 260 of 355 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 210 | 143 | 2 | 46 | 174 |
| 2021 | 220 | 131 | 2 | 46 | 159 |
| 2022 | 230 | 128 | 0 | 44 | 133 |
| 2023 | 205 | 148 | 2 | 47 | 208 |
| 2024 | 260 | 94 | 1 | 41 | 156 |
| 2025 | 245 | 107 | 2 | 43 | 159 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near New Haven-Milford, CT (43).
Ashtabula, OH
Median AQI 43 · 81.2% Good-day share
Bloomington, IN
Median AQI 43 · 67.7% Good-day share
Champaign-Urbana, IL
Median AQI 43 · 65.8% Good-day share
Cleveland, MS
Median AQI 43 · 71.9% Good-day share
Columbus, IN
Median AQI 43 · 72.6% Good-day share
Durham-Chapel Hill, NC
Median AQI 43 · 71.5% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to New Haven-Milford, CT's 2 (independent of median AQI).
Ardmore, OK
2 unhealthy-or-worse days · median AQI 45
Bridgeport-Stamford-Norwalk, CT
2 unhealthy-or-worse days · median AQI 44
Chattanooga, TN-GA
2 unhealthy-or-worse days · median AQI 49
Cincinnati, OH-KY-IN
2 unhealthy-or-worse days · median AQI 56
Columbus, GA-AL
2 unhealthy-or-worse days · median AQI 48
Davenport-Moline-Rock Island, IA-IL
2 unhealthy-or-worse days · median AQI 46
Frequently Asked Questions
What is the 90th percentile AQI for New Haven-Milford, CT? ▼
How many unhealthy air days does New Haven-Milford, CT have? ▼
What is the air quality in the New Haven-Milford, CT metro area? ▼
Is air quality in New Haven-Milford, CT getting better or worse? ▼
What does AQI 43 mean for health? ▼
How does New Haven-Milford, CT compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for New Haven-Milford, CT, 2025. See our methodology for how AQI, median, and coverage figures are computed.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, New Haven-Milford, CT · 2020–2025