Wildfires in Canada are sending heavy smoke across the northern U.S., and New Jersey is experiencing some unhealthy air pollution. The air quality has some Northeasterners wondering, what is the AQI, or Air Quality Index? AQI, or Air Quality Index, is the measure of how healthy or unhealthy the air is.

The EPA says if you are sensitive to particle pollution, consider reducing your activity level or shorten the amount of time you are outdoors.

Air quality alerts were issued in North Jersey Aug. 5 as smoke from Canadian wildfires drifts across the northern United States.