As wildfires have choked skies in the western United States, turning them vivid orange or sickly ochre, millions of people now live where smoke regularly makes breathing unhealthy, according to new estimates from a team based at Stanford University.
In California, Unhealthy Pollution From Wildfire Smoke Has Become Dangerously Common kcrw.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from kcrw.com Daily Mail and Mail on Sunday newspapers.