Ozone affecting air quality in southern Connecticut Thursday, officials say

Connecticut officials said elevated ground-level ozone is affecting air quality across much of southern Connecticut on Thursday, July 9, 2026, as hot, sunny and humid conditions support ozone formation.

Much of the shoreline and southern inland part of the state is in the orange range, or unhealthy for sensitive groups, according to the Connecticut Department of Energy and Environmental Protection. The rest of Connecticut, including northern areas and part of southwestern Fairfield County, is in the yellow moderate range.

The advisory is tied to ground-level ozone, which forms when pollutants from cars and other sources react with sunlight. In summer, heat and sunshine can push levels higher, especially when humidity is also elevated.

Who is most at risk

Sensitive groups include children, older adults and people with asthma or chronic lung or heart conditions. Those residents may be more likely to experience worsened symptoms or more breathing trouble when ozone levels rise.

The general public is less likely to be affected, but officials typically advise people to limit strenuous outdoor activity during orange air quality periods if they are vulnerable to respiratory problems.

Weather setup

The ozone alert comes as Connecticut faces a warm, humid Thursday with a chance of afternoon thunderstorms. Those same conditions can influence how much ozone builds up during the day.

CT Insider reported earlier Thursday that the weather pattern could keep inland temperatures in the 80s while adding enough humidity and sun to support higher ozone later in the day.

What to watch next

This is a recurring summer pattern in Connecticut, and officials may update the forecast if storms, clouds or changing winds reduce ozone formation later Thursday or into Friday.

Residents in the affected shoreline and southern inland towns should check for any updated air quality maps or local guidance before spending extended time outdoors.