The National Weather Service (NWS) issued air alerts for the states of Iowa, Illinois, Wisconsin, Michigan and Indiana.

Warnings were also issued for parts of Pennsylvania and New York, while some government agencies asked residents to limit their time outdoors because of the smoke, which also affects visibility conditions.

A forecast model by the National Oceanic and Atmospheric Administration also forecast that surface smoke will travel eastward during the day, covering Pittsburgh, Raleigh, North Carolina and other cities.

Chicago, Illinois, reported the worst air quality on Tuesday, according to IQAir.com.

Chicago’s index was in the “very unhealthy” category for all age groups; and its Mayor Brandon Johnson said the situation was being carefully monitored and precautions were being taken.

“We highly recommend children, teenagers, the elderly, patients with heart or lung disease and pregnant women avoid strenuous activity and limit their time outdoors,” Johnson said.

Likewise, New York Mayor Eric Adams asked citizens to wear face masks to minimize risks and to avoid activities requiring being outdoors given adverse conditions that are expected to affect the region in coming hours.

Ohio health officials joined other states in warning residents to take precautions due to the harmful effects of the unhealthy environment.

“This is the second time in three weeks that smoke from Canadian wildfires moving south has caused air quality issues in Ohio,” Bruce Vanderhoff, director of the state Department of Health, said in a statement.

Currently, there are 490 wildfires burning on Canadian territory, of which 255 are considered out of control.

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