Canadian wildfire smoke spreads, 100 million Americans under air-quality alerts
By Brendan O’Brien CHICAGO (Reuters) -Murky, dull skies loomed over tens of millions of Americans on Thursday as smoke from prolonged Canadian wildfires drifted across the Midwest and East, causing unhealthy and, in some spots, dangerous conditions. Air-quality alerts were in effect until midnight for a swath of the United States that extended from Wisconsin…