Wildfire smoke triggers widespread air quality alerts across U.S.

Smoke from wildfires burning in both the western United States and Canada is blanketing large parts of the country.

(CNN)- Smoke from wildfires burning in both the western United States and Canada is blanketing large parts of the country, triggering air quality alerts and health concerns for millions of Americans.

“The past couple days has been a little rough,” said Lina Wentzel of Wisconsin. “You can definitely feel the heaviness of it.”

On Tuesday, air quality alerts were in effect across 11 states in the Midwest and Northeast, largely due to smoke drifting south from Canadian wildfires.

In Southern California, the Gifford Fire—now the state’s largest blaze of the year—has burned nearly 84,000 acres since igniting on Friday. As of Tuesday evening, it was only 9% contained. The fire has prompted evacuations in parts of two counties, and fire officials say the situation remains dangerous.

“Conditions can change rapidly, and the next thing you know, they’re experiencing fire activity that they can’t even imagine,” said Capt. Scott Safechuck with the Santa Barbara County Fire Department.

Nearby, the Rosa Fire in Riverside County has also caused evacuations and filled the sky with thick smoke and haze. That fire had burned more than 1,600 acres and was just 15% contained as of Tuesday night.

As fires continue to burn, officials are urging residents to stay indoors when possible, monitor local air quality indexes, and take steps to protect their health.