Metro area air quality · 2025

New Haven-Milford, CT

Median AQI 44 (Good). 68.5% of monitored days rated Good across this metro's EPA monitoring network.

44
Median AQI
68.5%
Good-air days
1
Unhealthy days
42%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 181 monitored days. EPA AQS →

The verdict

The New Haven-Milford, CT metro runs good on the EPA scale, more polluted than the median US metro, a median AQI of 44 with 68.5% of 181 monitored days in the Good band.

44
median AQI · Good
68.5%
days rated Good
42%
cleaner than US metros
151
worst single reading

1 day reached Unhealthy or worse across the metro's monitors in 2025.

Insights: New Haven-Milford, CT metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 44 over 181 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 124 Good days (69%), 52 Moderate (29%), and 4 Unhealthy-for-Sensitive-Groups (2%). The 90th-percentile AQI finished at 67 while the highest single-day reading hit 151 (Unhealthy). Metro residents averaged roughly 20.6 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -86 and the median AQI moved -2 points, which classifies the multi-year trajectory as improving. The metro recorded 1 unhealthy-or-worse days combined, on those days the EPA recommends that sensitive groups limit prolonged outdoor exertion, and many schools and athletic programs adjust outdoor activity accordingly. Metros with comparable AQI profiles include Athens-Clarke County, GA (66.7% good, AQI 44); Bartlesville, OK (65.6% good, AQI 44); Bloomington, IL (64.1% good, AQI 44).

Air Quality Summary

Median AQI

44

Good

Good Days

68.5%

124 of 181 days

Max AQI

151

Unhealthy

Health Grade

Moderate

90th pct: 67

AQI Day Breakdown (2025)

Distribution of 181 monitored days across EPA AQI categories.

Good

124

69%

Moderate

52

29%

USG

4

2%

Unhealthy

1

1%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The New Haven-Milford, CT metro area's air quality is rated Moderate based on 68.5% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.

Air quality is acceptable most days, but 4 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 151. 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

Good-day share worse than US avg
New Haven-Milford, CT 68.5%
Athens-Clarke County, GA 66.7%
US average 71.3%
Median AQI worse than US avg
New Haven-Milford, CT 44
Athens-Clarke County, GA 44
US average 41
Unhealthy days / yr about average
New Haven-Milford, CT 1
Athens-Clarke County, GA 0
US average 1

5-Year Air Quality Trend

Air quality is improving in the New Haven-Milford, CT metro. Best year: 2024 (260 good days).

Year Good Moderate Unhealthy Median AQI
2020 210 143 2 46
2021 220 131 2 46
2022 230 128 0 44
2023 205 148 2 47
2024 260 94 1 41
2025 124 52 1 44

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to New Haven-Milford, CT.

Athens-Clarke County, GA

AQI 44 · 66.7% good

44

Bartlesville, OK

AQI 44 · 65.6% good

44

Bloomington, IL

AQI 44 · 64.1% good

44

Boston-Cambridge-Newton, MA-NH

AQI 44 · 68.3% good

44

Bridgeport-Stamford-Norwalk, CT

AQI 44 · 66.8% good

44

Buffalo-Cheektowaga-Niagara Falls, NY

AQI 44 · 61.3% good

44

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Cleanest Metro Areas

U.S. metros ranked by their share of Good air-quality days.

Worst Air Quality

Counties and metros with the most unhealthy air days.

All Metro Areas

Annual AQI by CBSA for every monitored U.S. metro area.

Best and Worst City Air

What drives urban air quality and how metro areas compare.

Air Quality Guides

Frequently Asked Questions

What is the air quality in the New Haven-Milford, CT metro area? ▼
The New Haven-Milford, CT metro area has a median Air Quality Index (AQI) of 44, rated "Good." 68.5% of monitored days (124 out of 181) had good air quality in 2025.
How many unhealthy air days does New Haven-Milford, CT have? ▼
In 2025, the New Haven-Milford, CT metro area recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 151.
Is air quality in New Haven-Milford, CT getting better or worse? ▼
Air quality in the New Haven-Milford, CT metro is improving based on 5-year trends (2020-2025). Best year: 2024 with 260 good days. Worst year: 2025 with 124 good days.
What does AQI 44 mean for health? ▼
An AQI of 44 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for New Haven-Milford, CT? ▼
The 90th percentile AQI for the New Haven-Milford, CT metro area is 67, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 151 (Unhealthy).
How does New Haven-Milford, CT compare to other metro areas? ▼
The New Haven-Milford, CT metro has 68.5% good air days. Similar metros: Athens-Clarke County, GA (66.7% good), Bartlesville, OK (65.6% good), Bloomington, IL (64.1% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. 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 files (metro-level) · 2020–2025

Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.