“It is a growing cardiovascular threat”: Chicago, Detroit, Minneapolis and New York City are considered some of the world’s most polluted cities Thursday.
Source: [MarketWatch](https://www.marketwatch.com/story/these-cities-are-blanketed-with-wildfire-smoke-heres-what-to-know-about-bad-air-quality-cd3a8fa7?mod=mw_rss_topstories)