An air quality health advisory was issued Wednesday for Long Island, New York City and the northern suburbs.
The state Department of Environmental Conservation said outdoor air quality was expected to exceed limits for ground-level ozone. Exposure to elevated ozone levels can cause breathing problems, aggravate asthma and other pre-existing lung diseases, and make people more susceptible to respiratory infection, officials said.
The state Department of Health recommends that people limit outdoor exercise.
The advisory was expected to be in effect until 11 p.m. Wednesday.
Patchy fog crept in across parts of Long Island Wednesday morning, with the National Weather Service urging rush-hour drivers to be careful.
Daily highs for Long Island are expected to reach the mid 80s, with hot, muggy conditions.
News 12 Long Island meteorologist Rich Hoffman said Wednesday is likely to remain dry but that an incoming cold front could bring a chance of rain Thursday night into Friday morning.