West Coast wildfires causing hazy summer days, striking evening sunsets in suburbs

Those hazy days of summer have become a lot hazier recently, and experts blame wildfires raging out West and in Canada.

Authorities say 80 large wildfires are now burning across the U.S., including 19 in Montana. More than 200 fires are burning in Manitoba and Ontario, according to Canadian officials.

Carried by winds, smoke from the wildfires covers much of the United States, affecting air quality.

The fires are also responsible for the setting sun appearing as a brilliant orange orb. That visually arresting image results from dust particles suspended in the atmosphere and absorbing light, said Brian Leatherwood, meteorologist with the National Weather Service in Romeoville.

“It's an interesting phenomenon,” he said. “(Dust particles) filter out more of the blue light and allow the red light to come through.”

Haze from the smoke stretches from the Great Plains north to Minnesota and North Dakota, east to the Appalachian Mountains and south to North and South Carolina. Gulf Coast states including Texas have also experienced its effect, Leatherwood said.

“It's very extensive,” Leatherwood said, adding that haze lingering over northern Illinois “is not going anywhere anytime soon.”

Leatherwood speculates it will extend into early next week.

Referencing a 48-hour weather service model, meteorologist Ricky Castro said “there's still a good amount of smoke forecast over the area.”

Experts blame global warming for the ever-intensifying blazes, which contribute to rising pollution levels that are especially harmful to people with chronic heart and lung diseases.

In fact, scientists have linked smoke exposure to long-term health problems including decreased lung function, weakened immune systems and higher rates of flu.

“It's certainly unhealthy,” Jeff Pierce, atmospheric scientist at Colorado State University, told The Associated Press. “If you have asthma or any sort of respiratory condition, you want to be thinking about changing your plans if you're going to be outside.”

• ABC 7 News and The Associated Press contributed to this report.