CHICAGO, July 16 (Xinhua) -- Chicago's famous skyline was engulfed in thick and hazardous haze and smoke Thursday as massive plumes of wildfire smoke poured into the United States, bringing dangerous air quality to more than 115 million people in the Midwest and Northeast.
The air quality index for Chicago rose to 477 as of 3 p.m. CDT (2000 GMT), a red category indicating "hazardous," according to AirNow.gov, a website dedicated to monitor air quality around the United States.
Air quality was also bad in northern Illinois and Wisconsin. Earlier Thursday, air quality index in some areas of the U.S. state of Michigan even reached the hazardous level of 500. Local TV stations have warned residents to avoid outdoor activities.
Residents in some parts of the U.S. states of Illinois and Michigan claimed that they could smell the smoke inside their homes. The Michigan Department of Health and Human Services has issued additional guidance to deal with the crisis, asking residents to stay inside and use air cleaners. Beaches and pools as well as national parks and other public lands in the Midwest area were all closed.
As elevated levels of fine particulates from the smoke drove air quality indexes well above the hazardous level, the National Weather Service issued Air Quality Alerts for the affected areas.
The current hazy and smoky air conditions in the United States are expected to last until Thursday night or Friday, according to AirNow.gov.
Some 3,500 fires have burned more than 6 million acres (about 2.43 million hectares) of Canadian land this summer, with a dozen blazes flaring up in Ontario in recent weeks, filling the skies with smoke drifting south, local media reported Thursday.
The last time Canadian wildfire smoke ravaged the U.S. was in 2023, when the U.S. hospitals reported a significant spike in patients seeking treatment for asthma and other respiratory illnesses.
