If you smelled something burning in the air or if your allergies are really bothering you, you are not alone. There is smoke in the Windy City and around the Chicago area, and it's coming from hundreds of miles away.
"We live in southern California. From time to time, from the fires, we get the Santa Ana winds and somebody sets off a fire," said Dave Denham, visiting from California.
For those visiting from California and Texas where wildfires are common, the smell of smoke is recognizable.
"It was, unfortunately, a familiar smell. I was hoping to come up and have nice fresh air for a change, and instead got the familiar smell of smoke," said Ray West, Texas.
Because of the smoke, doctors have been seeing people with respiratory issues. The smoke increases the mold in the air. It was at the highest level all year Tuesday. Patients are advised to stay inside, drink as much water as possible and limit exercise, especially outdoors.
"The air is saturated with garbage. There isn't enough oxygen, and then what happens, eyes get watery and stuffiness and we feel lousy," said Dr. Joseph Leija, Gottlieb Memorial Hospital.
Some people in the Chicago area thought there was a fire nearby and called authorities.
"We had about three or four runs that we made today that were false alarms, but just better to be safe than sorry," Elmhurst Mayor Pete DiCianni said Tuesday.
The smoke could be gone by the end of Wednesday, depending on the wind patterns.
ABCNews reports that the fire, 600 miles away, has been burning for nearly a month. The haze is so bad, the Milwaukee Brewers had to close the roof of their stadium during Tuesday night's game.
Forest Service spokeswoman Lisa Radosevich-Craig says the fire in the Boundary Waters Canoe Area Wilderness, which has swallowed at least 100,000 acres, is not expected to grow more than a quarter of a mile Wednesday because of lighter winds.
Radosevich-Craig says the wildfire is the biggest in terms of acreage in northeast Minnesota. She says 200 highly experienced firefighters from federal and state agencies are expected to arrive Wednesday and Thursday to battle the fire that was ignited by a lightning strike Aug. 18.
The Associated Press contributed to this report.