LOUISVILLE, Ky. (WDRB) -- Visibility in the Louisville area was down to two miles as another Air Quality Alert was issued for Kentuckiana on Wednesday. 

Drifting smoke from Canadian wildfires continues to hang over the area. Louisville is one of several major cities affected by the smoke as it settles over southern Illinois, Indiana and Ohio, and moves into parts of West Virginia.

Across Canada, 490 fires are burning, with 255 of them considered to be out of control.

On Wednesday the AirNow.gov site listed Louisville's air quality as "unhealthy." The site lets people type in their zip code to see what the air quality is in their area. 

On Wednesday the site rated the air in Cleveland, Indianapolis, Chicago, and Pittsburgh, as "very unhealthy."

Dr. Steven Patton, a Norton Healthcare physician, encouraged people to take precautions.

"Too long of exposure to these small particles in a day can kind of be like smoking a cigarette," said Patton.

Children and older adults as well as people with lung and heart disease should limit their time outside, take more breaks and do less intense activities. People should look for symptoms like coughing and shortness of breath.

Alfred Cummings, who lives in Jeffersonville, noticed the air quality as soon as he walked outside.

"I've been having a hard time breathing," said Cummings.

Jake Roby couldn't see much on Wednesday because of the wildfires.

"Like from on the highway normally you can see downtown, couldn't see it at all, so it was nuts," Roby said.

A family from Wisconsin was passing through Louisville on their way to Asheville, North Carolina. They've seen worse haze further north.

"It's hazy, but it's actually worse in Wisconsin for us and it's been worse the whole way down here, so it's more clear than it is in Wisconsin," said Stephanie Ferguson. 

Flights weren't able to take off from Bowman Field because of the smoke and haze on Wednesday.

The air quality alert will remain in effect through Thursday in Kentucky and southern Indiana. 

A heat advisory has also been issued for Friday morning for the Greater Louisville area, with heat indexes expected to approach 105.

The advisory will take effect Thursday afternoon for Dubois and Perry County. 

People in sensitive groups such as pregnant women, the elderly, young children and people with respiratory illnesses should avoid heavy outdoor exertion and try to finish outdoor activities in the morning, when levels are lower. Pay attention to related symptoms and make sure to have a rescue inhaler.

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