Canadian wildfire smoke spreads across a third of US

DULUTH, Minnesota — Smoke from wildfires burning in three Canadian provinces is spreading into the U.S. Upper Midwest, stirring memories of the severe pollution that drifted south from Canada two years ago during that country’s worst fire season on record.

The particulate matter pollution caused by the smoke is already blowing into Minnesota and neighboring states, posing a health risk to the tens of millions who live in the region. It is expected to make its way to New York and other East Coast cities in less severe levels over the coming days.

“Airborne particulate matter is the most serious environmental health risk we know of,” said Doug Brugge, a public health researcher at the University of Connecticut School of Medicine. “It causes cardiovascular, respiratory and neurological harm