Air quality plummets in 20 US states as smoke from Canadian wildfires spreads

The brief

Smoke from wildfires burning in south-central Canada and parts of Minnesota is spreading across the US, prompting air quality alerts in more than 20 states with millions of Americans expected to face unhealthy air conditions this week. The smoke from the more than 180 active wildfires in northern Ontario made Chicago’s air quality the worst in the world on Thursday evening, followed by Detroit and Minneapolis, according to IQAir’s global rankings. The smoke has spread across several US states, from Minnesota, where multiple wildfires are also burning, to New York state, blanketing the skies in haze and worsening air quality. In New York City, where the sky was tinged with…