PM Standards
Announcements
September 21, 2006 - EPA strengthens National Ambient Air Quality Standards for Particle Pollution.
- Learn more about today's action
- Final Rule
- Fact Sheet (PDF, 8 pp, 63 KB)
The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) for six criteria pollutants, particle pollution (also known as particulate matter) is one of these. The Clean Air Act established two types of national air quality standards for particle pollution. Primary standards set limits to protect public health, including the health of "sensitive" populations such as asthmatics, children, and the elderly. Secondary standards set limits to protect public welfare, including protection against visibility impairment, damage to animals, crops, vegetation, and buildings.
The nation's air quality standards for particulate matter were first established in 1971 and were not significantly revised until 1987, when EPA changed the indicator of the standards to regulate inhalable particles smaller than, or equal to, 10 micrometers in diameter (that's about 1/4 the size of a single grain of table salt).
Ten years later, after a lengthy review, EPA revised the PM standards, setting separate standards for fine particles (PM2.5) based on their link to serious health problems ranging from increased symptoms, hospital admissions and emergency room visits for people with heart and lung disease, to premature death in people with heart or lung disease.
The 1997 standards also retained but slightly revised standards for PM10 which were intended to regulate "inhalable coarse particles" that ranged from 2.5 to 10 micrometers in diameter. PM10 measurements, however, contain both fine and coarse particles.
EPA revised the air quality standards for particle pollution in 2006. The 2006 standards tighten the 24-hour fine particle standard from the current level of 65 micrograms per cubic meter (µg/m3) to 35 µg/m3, and retain the current annual fine particle standard at 15 µg/m3. The Agency decided to retain the existing 24-hour PM10 standard of 150 µg/m3. The Agency revoked the annual PM10 standard, because available evidence does not suggest a link between long-term exposure to PM10 and health problems.
The Clean Air Act requires EPA to review the latest scientific information and standards every five years. Before new standards are established, policy decisions undergo rigorous review by the scientific community, industry, public interest groups, the general public and the Clean Air Scientific Advisory Committee (CASAC). More about the process of reviewing the standards.
(see the complete table of National Ambient
Air Quality Standards at http://www.epa.gov/air/criteria.html) |
Related Documents
- Documents from the Current Review of the PM Standards
- Documents from Review Completed in 2006
- Documents from Review Completed in 1997
For more information
- PM Standards Revision - 2006
- Process of Reviewing the Standards
- History of PM Standards
- Technical Information
- Greenbook
- PM Designations
- PM10 Implementation
- PM2.5 Implementation