Wildfire smoke worsens air quality across North America.

Smoke from hundreds of wildfires in Canada has engulfed the eastern United States, causing "Code Red" air quality alerts and health concerns for tens of millions of Americans. New York City was particularly affected, with a thick haze blanketing the Statue of Liberty and delaying a baseball game at Yankee Stadium. Schools cancelled field trips and moved recess indoors in Philadelphia and Washington, while in Binghamton, N.Y., the sky turned orange and the parking lot lights came on. Canadian officials reported more than 400 active fires, with roughly 240 listed as "out of control." The drier weather and high temperatures fueled by a warming atmosphere are exacerbating the damage, Canadian officials say.