Air quality warnings have been issued in more than a dozen states.
Hundreds of wildfires burning in Canada continue to cause poor air quality for millions of residents in the United States.
On Wednesday, the National Weather Service issued air quality warnings for at least 20 states as far south as Minnesota and Georgia. Unhealthy air quality warnings have also been extended to parts of the Northeast, including New York state and New Jersey.
Smoke will continue from Minnesota to Washington, DC and the Carolinas by Wednesday afternoon. As of Wednesday, Chicago, Detroit and Minneapolis rounded out the top five places for the world’s worst air quality. IQAirIt monitors air quality worldwide.
By Thursday morning, cities such as Minneapolis, Chicago, Indianapolis, Atlanta and Pittsburgh will be affected by the smog, according to forecasts.
Smoke will linger Thursday afternoon from Detroit to Atlanta and east to near Washington, DC and Philadelphia. The fog is not expected to clear until Thursday afternoon.
Poor air quality is not expected to affect New York City, but will be in western New York, Pennsylvania and southern New Jersey, projections show.
Smoke from nearly 500 wildfires burning in Canada has been drifting toward the United States for more than a month, after an unprecedented start to the season that has already burned 19.5 million acres. Canada has broken its own record for annual wildfire smoke emissions.
Due to the dry climate and intense heat in the region, forest fires are never ending.
According to IQAir, parts of the Midwest, including areas around Minnesota, measured some of the world’s lowest air quality on Tuesday morning.
Chicago’s air quality hit the “very unhealthy” category as the air quality index climbed to 250 on Tuesday afternoon. Any number above 100 is considered unhealthy for sensitive groups, and 250 or “code purple” is considered extremely unhealthy for all groups.
Once the AQI reaches 151 and above, breathing polluted air can cause a number of symptoms — even in healthy people without pre-existing conditions — including weakening the immune system and damaging the body, including the lungs and heart.
Exposure to concentrated levels of PM2.5 can cause short-term effects such as eye, nose and throat irritation; Long-term effects such as coughing, sneezing and shortness of breath, and worsening of conditions including asthma and heart disease US Environmental Protection Agency