"Smoke from Canadian wildfires blankets eastern U.S., millions advised to stay indoors"

Millions of Americans have been warned to stay indoors as smoke from hundreds of wildfires in Canada has spread to the eastern states of the US, causing hazardous air quality. The smoke contains particulate matter that can cause lung damage in the short and long term, as well as harmful gases. Authorities have advised young children, the elderly, and those with respiratory issues to stay indoors.