This is the ultimate fact sheet for debunking what has become the U.S. Environmental Protection Agency’s most potent regulatory weapon — the claim that fine particulate matter (soot and dust called PM2.5) in outdoor air kills people.
What is PM2.5? PM2.5 (see image below) is very small/fine soot and dust in the air. It has natural sources (e.g., forest fires, volcanoes, pollen, molds) and manmade sources (e.g., smokestack/tailpipe emissions, fires (fireplaces, campfires, grills), smoking). Depending on source, PM2.5 will vary in composition (i.e., PM2.5 in smoke is different than pollen PM2.5).
Although EPA claims that almost 25% of annual U.S. deaths are caused by PM2.5, no death has ever been medically attributed to PM2.5.
Despite much research, there is no generally accepted medical or biological explanation for how PM2.5 could possibly cause death.
