# Connecticut air quality today — live AQI by metro

> Source: https://breathecheck.com/air-quality/us/connecticut/
> Live AQI for 2 Connecticut metros, updated hourly from EPA AirNow. Where the state's air is worst right now, and how far apart its cities are.

# Connecticut air quality today

Updated 14 Sep 2026, 22:12 UTC · LIVE 2 metros tracked

Across the 2 Connecticut metros BreatheCheck measures, air is worst right now in Hartford at AQI 28 (Good) and cleanest in Bridgeport at AQI 12 .

## Which Connecticut city has the worst air quality right now?

| # | Metro | AQI | UV now | Dominant |

| 1 | Hartford no page yet | 28 Good | 0.2 | O3 |

| 2 | Bridgeport no page yet | 12 Good | 0.2 | PM2.5 |

## What is the UV index in Connecticut today?

The strongest UV in Connecticut today is 5.9 (High) in Bridgeport, arriving around 1pm local time. The mildest of the 2 metros we model here peaks at 5.8 in Hartford.

UV is modelled, not measured — unlike the AQI above it, which comes off an instrument. How we handle UV →

## A sea breeze that delivers New York's ozone

The ozone Connecticut fails on is largely made somewhere else. Precursors leaving the New York City area drift northeast over Long Island Sound, where relatively cool water holds them in a shallow, stable marine layer instead of letting them mix upward and thin out. Afternoon heating over the Connecticut shore then draws a sea breeze inland, and that breeze delivers the confined layer onto land. Monitors in Fairfield, New Haven and Middlesex counties read the result; on some days the same air keeps going east into Rhode Island and Massachusetts.

The Department of Energy and Environmental Protection, DEEP, puts a number on the attribution: the worst observed air quality in Connecticut is 95 percent due to emissions other than Connecticut’s own sources. Southwest Connecticut is the Connecticut piece of the New York-Northern New Jersey-Long Island multistate nonattainment area, which EPA reclassified to severe under the 2008 ozone standard in 2022, with an attainment deadline of July 2027. DEEP’s stated position is that the problem in southwest Connecticut is solvable only if upwind states fully address their obligations under the Clean Air Act’s Good Neighbor provisions — an unusual thing for a state agency to say about its own designation, and a direct product of where the Sound sits. The Long Island Sound Tropospheric Ozone Study, a 2018 field campaign run by NASA, NOAA, EPA, NESCAUM and state agencies, was built around measuring that plume as it moved over the water.

In practice: a hot, still July afternoon on the shoreline can produce the state’s highest ozone with Connecticut’s own traffic doing nothing out of the ordinary. DEEP forecasts elevated ozone days ahead of heat waves and announces them publicly.

## Where do these Connecticut readings come from?

2 of the 2 metros here report from a named regulatory monitor — Bridgeport, Hartford. The dominant pollutant across Connecticut today is PM2.5 in some metros, O3 in others.

We track 2 metropolitan areas in Connecticut, not the whole state, and none of them has its own page yet — we publish a metro page where searches for it clear a floor, and none here does, though every one is measured hourly. There is no state-wide average here on purpose: averaging 2 metros into one figure would invent a value for all the ground between them. How we measure, and what we refuse to estimate →

## Neighbouring states

Smoke and inversions do not stop at a state line, so when Connecticut looks wrong the answer is often next door.

## Related

Updated 14 Sep 2026, 22:12 UTC