The Connecticut Department of Energy and Environmental Protection (DEEP) is forecasting unhealthy air quality for “sensitive groups” on Friday, August 3 and Saturday, August 4 due to elevated concentrations of ground-level ozone pollution for all of Fairfield, southern Litchfield, New Haven, Hartford, and Tolland counties.

A forecast of “Unhealthy for Sensitive Groups” indicates increased likelihood of respiratory symptoms and breathing discomfort in active children and adults with respiratory disease, such as asthma.
Ground level or "bad" ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of NOx and VOC.