For ozone pollution in the state, both Middlesex and Fairfield Counties maintained F grades.
Fairfield County recorded over 20 unhealthy ozone days. In Litchfield County, the number of unhealthy days for short-term particle pollution more than tripled - dragging its grade down from a B in last year's report to a D this year.
The report states that both ozone smog and daily particle pollution worsened in the New Haven-Hartford-Waterbury metro area, earning it the ranking of 38th-most polluted metro area in the nation for ozone and 70th worst for particle pollution.
The report rated 7 out of 8 counties with a grade of D or F. Windham County rated a C.