New York state has issued an air quality alert for the five boroughs as wildfires continue to burn in Canada. 

The Department of Environmental Conservation’s health advisory, which is in effect until midnight on Friday, includes Long Island and Westchester, Rockland, Orange and Putnam counties, as well as New York City. 

The alert comes weeks after the city recorded its worst air quality in 21 years and dealt with hazy, smoky conditions. 

Conditions are expected to be far less severe than they were earlier this month, when the air quality index soared above 400. 

While the state has not advised New Yorkers to remain indoors, they are being encouraged to “consider limiting strenuous outdoor physical activity to reduce the risk of adverse health effects.” 

“People who may be especially sensitive to the effects of elevated levels of pollutants include the very young, and those with preexisting respiratory problems such as asthma or heart disease,” the National Weather Service said on its website. 

The MTA is distributing free N95 masks at a number of subway, Long Island Rail Road and Metro-North Railroad stations, including Penn Station and Grand Central Terminal.