In Pennsylvania, Bucks, Chester, Delaware, Montgomery, and Philadelphia counties are under the air quality alert.
The New Jersey counties under the air quality alert include Atlantic, Ocean, Burlington, Cape May, Mercer, Monmouth, Salem, Cumberland and Middlesex counties.
An "Orange Alert" means air pollution concentrations within the region may become unhealthy for people of sensitive groups.
Sensitive groups include children, people suffering from asthma, heart disease or other lung diseases, as well as the elderly.
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Those within the group are advised to avoid strenuous activity or exercising outdoors.
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