Particulate Matter Pollution
For detailed information about real-time pollution levels, visit the EPA website.
What is Particulate Matter?
The term Particulate Matter (PM) includes both solid particles and liquid droplets found in air. Many man-made and natural sources emit PM directly or emit other pollutants that react in the atmosphere to form PM. These solid and liquid particles come in a wide range of sizes. Particles less than 10 micrometers in diameter tend to pose the greatest health concern because they can be inhaled into and accumulate in the respiratory system. Particles less than 2.5 micrometers in diameter are referred to as "fine" particles. Sources of fine particles include all types of combustion (motor vehicles, power plants, wood burning, etc.) and some industrial processes. Particles with diameters between 2.5 and 10 micrometers are referred to as "coarse". Sources of coarse particles include crushing or grinding operations, and dust from paved or unpaved roads.
The Environmental Protection Agency uses its Air Quality Index to provide general information to the public about air quality and associated health effects. An Air Quality Index (AQI) of 100 for any pollutant corresponds to the level needed to violate the federal health standard for that pollutant. For PM2.5, an AQI of 100 corresponds to 40 micrograms per cubic meter (averaged over 24 hours) -- the current federal standard. An AQI of 100 for PM10 corresponds to a PM10 level of 150 micrograms per cubic meter (averaged over 24 hours).
Particulate Matter Health Hazards
Particulate Matter Standards
In 1997 the Environmental Protection Agency (EPA) proposed a new standard of ozone and particulate matter levels in the atmosphere. The particulate matter levels of up to 10 microns in diameter(PM10) at each monitor within an area must not exceed 150 µg/m3, in one hour more than once per year, averaged over 3 years. The particulate matter levels of up to 2.5 microns in diameter (PM2.5), must not exceed 15 micrograms per cubic meter (µg/m3) and 65 µg/m3, respectively, each year and 24-hour period.
However, a coalition of business and industry interests sued to have those standards blocked, claiming they were too expensive and ill-conceived. In 1999 a federal court agreed, issuing a ruling blocking implementation of the tougher standards. Changes were made again in February 2001, when the U.S. Supreme Court unanimously upheld the constitutionality of the Clean Air Act as EPA had interpreted it in setting health-protective air quality standards for ground-level ozone and particles. The Supreme Court also reaffirmed EPA's long-standing interpretation that it must set these standards based solely on public health considerations without consideration of costs.
However, the Supreme Court did find that the EPA's plans for implementing the rules were unreasonable, and it ordered the agency to develop new implementation policies. Industry opponents immediately promised to use this aspect of the ruling as the basis for new legal challenges to weaken implementation of the new standards. It remains to be seen if the new standards will truly take effect as legislated.
According to the EPA, the new particulate matter and ozone standards will have the following effects:
Reduced risk of moderate to severe respiratory symptoms in children. The new standards should result in hundreds of thousands of fewer incidences each year of symptoms such as aggravated coughing and difficult or painful breathing.
Reduced risk of hospital admissions and emergency room visits for respiratory causes. The new standards should result in thousands fewer admissions and visits for individuals with asthma.
Reduced risks of more frequent childhood illnesses and more subtle effects such as repeated inflammation of the lung, impairment of the lung's natural defense mechanisms, increased susceptibility to respiratory infection, and irreversible changes in lung structure. Such risks can lead to chronic respiratory illnesses such emphysema and chronic bronchitis later in life and/or premature aging of the lungs.
Reduce the yield loss of major agricultural crops, such as soybeans and wheat, and commercial forests by almost $500,000,000.
What are the health effects from Particulate
What Parents Need to Know About
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