What did EPA do with the particulate matter standards?
EPAs revision of the particulate matter standard: • Strengthened the 24-hour fine-particle standard from 65g/m3 (micrograms per cubic meter) to 35g/m3. • Retained the annual fine-particle standard at 15g/m3. • Retained the national 24-hour PM10 standard of 150g/m3. • Revoked the annual PM10 standard because available evidence generally did not suggest a link between long-term exposure to coarse particles and adverse health effects. • Set secondary PM standards equivalent to the levels of the primary standards. Secondary standards are those standards that target other effects of pollutants such as visibility impairment and soiling.
