The Smallest of Pollutants Are Linked to Outsize Health Risks

Sitting in traffic triples a person's short-term heart-attack risk. Living in a city with heavy air pollution such as Los Angeles is as risky for the heart as being a former smoker. And having a house near a highway ups the risk of hardened arteries by some 60 percent. In each case, tiny "ultrafine" particles in the air may be a key culprit.

The Smallest of Pollutants Are Linked to Outsize Health Risks