The Environmental Protection Agency released the final version of a much-anticipated rule on Wednesday that tightens restrictions on fine particulate matter — one of the most pervasive and dangerous forms of air pollution. This is the EPA’s first update to its particulate matter standard in more than a decade, and the agency said it expects the new rule to save thousands of American lives every year.
Fine particulate matter, or PM2.5, is a category of tiny air-borne particles produced by power plants, forest fires, and industrial factories, among other sources. The minuscule bits of matter are roughly 30 times smaller than the width of a human hair and can lodge deep inside human lungs. PM2.5, often referred to as soot, is linked to serious health problems, such as asthma, lung and heart disease, and respiratory symptoms. One in three Americans