A new study links even small reductions in fine particle air pollution to increased life expectancy.
Researchers who compared data from 545 counties across the U.S., including many in California, found that a drop in fine particulate matter, known as PM2.5, between 2000 and 2007 corresponded with an average rise in life expectancy of 0.35 of a year.
The study, led by researchers at the Harvard School of Public Health, is described as the largest to date to find public health benefits from ongoing reductions in U.S. air pollution levels.
Fine particles, which are about 1/30th the average width of a human hair, come from a variety of sources, including vehicles, smokestacks and fires. They also form when gases emitted by power plants, industry and vehicle engines react in the atmosphere.
The tiny particles can lodge deeply in the lungs, aggravating heart and lung diseases. Those most at risk include people who are active outdoors, children and the elderly.