June, 26 2026, 02:47pm EDT Court Upholds Life-Saving National Soot Air Quality Standard Today, the U.S. Court of Appeals for the D.C. Circuit upheld the national, health-based limit on fine particulate matter (PM2.5), also known as soot, that the Environmental Protection Agency (EPA) strengthened in 2024. Soot, made up of tiny toxic particles that lodge deep in the lungs, results in severe health ...