More Canadian wildfire smoke shrouds US midwest, mid-Atlantic and north-east

The brief

Tens of millions of Americans are enduring another day of smoky skies, irritated eyes and bad air quality, as Canadian wildfire smoke spread again over huge swathes of the US, affecting about 109 million people across the midwest, mid-Atlantic and north-east. The pungent smoke blanketed cities such as Chicago and Detroit, where residents on Friday were warned to stay indoors and reduce activity levels after the air-quality index reached a “hazardous” 361, according to the government website AirNow. As smoke plumes swirled around the eastern US, mostly from about 200 out-of-control wildfires in Canada, Donald Trump threatened to impose additional tariffs on its northern neighbor, with the US president accusing…