The action significantly strengthens EPA's previous daily fine particle standard – by nearly 50 percent – from 65 micrograms of particles per cubic meter to 35 micrograms of particles per cubic meter of air. According to EPA, this standard increases protection of the public from short-term exposure to fine particles and will reduce premature deaths, heart attacks and hospital admissions for people with heart and lung disease. The EPA is also retaining the current annual standard for long-term exposure to fine particles at 15 micrograms per cubic meter. Based on recently updated benefits estimates, meeting this standard will result in benefits ranging from $20 billion to $160 billion a year, the EPA says.
PM is a complex mixture of extremely small particles and liquid droplets in the air (i.e. dust, soot and particles too small to see). The standards address two categories of particle pollution: fine particles and inhalable coarse particles. Fine particles are 2.5 micrometers in diameter and smaller; inhalable coarse particles have diameters between 2.5 and 10 micrometers. Exposure to particle pollution is linked to a variety of significant health problems ranging from aggravated asthma to premature death in people with heart and lung disease.
"Regardless of the rhetoric, facts are facts – EPA is delivering the most health protective national air standards in U.S. history to all 300 million Americans," says EPA Administrator Stephen L. Johnson.
The EPA is retaining the existing daily PM10 standard of 150 micrograms per cubic meter. This standard protects against premature deaths and increased hospital admissions for individuals with heart and lung disease, according to the EPA. The EPA is revoking the annual coarse particle standard because it says the available evidence does not suggest an association between long-term exposure to coarse particles at current ambient levels and health effects.
EPA selected the levels for the final NAAQS after reviewing thousands of peer-reviewed scientific studies about the effects of particle pollution on public health and welfare. The agency also carefully considered public comments on the proposed standards. EPA held three public hearings and received more than 120,000 written comments.
States must meet the revised standards by 2015, with a possible extension to 2020, depending on local conditions and the availability of controls, the EPA says.
