https://www.wired.com/story/air-pollution-is-still-killing-thousands-of-people-in-the-us/

Soot kills. Still! Even in America, even in 2019. Those suspended fragments and droplets smaller than 2.5 micrometers across, small enough to be inhaled into the deepest recesses of the lungs and slip into the bloodstream—that’s soot. Or PM2.5 in technical terms. Breathing it in can inflame airways, triggering respiratory troubles, heart problems, even dementia. And, as study after study have shown, these adverse health effects can trim years off a person’s life.

The situation is most dire in China, India, and other parts of Southeast Asia. Yet even in the US, which has stricter laws and cleaner air, the levels of particulate pollution permitted by the Environmental Protection Agency still claim the lives of thousands of people every year. That’s the message behind a massive new study published today in JAMA Network Open. The investigation combined EPA air quality data with a decade of medical records for 4.5 million US veterans to find links between chronic PM2.5 exposure and nearly 200,000 deaths.