The New Jersey Department of Environmental Protection issued an air quality alert for Bergen, Passaic, Hudson, Essex and Union counties from 11 a.m. to 11 p.m. Wednesday.
North Jersey temperatures were breaking into the 90s -- and expected to climb even higher on Thursday, AccuWeather says.
The "real feel" in some places will be more like 100 degrees, thanks to swelling humidity that will make breathing difficult for many.
"Ozone is forecast to reach the unhealthy level for sensitive groups," AccuWeather reports.These include the very young, the elderly and those with asthma and other respiratory illnesses.
The hope is that the heat/humidity coupling will eventually produce thunderstorms later in the week to cool things off somewhat.
Until then, experts advise drinking plenty of water, avoiding strenuous outdoor activity while the sun is strongest and wearing light-colored, light-fitting clothing.
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