Particulate Matter (PM)
The Issue
Particulate matter is a complex mixture of extremely small particles and liquid droplets in the air. Particulate matter causes concern because it is associated with serious health effects such as aggravated asthma, difficulty breathing, chronic bronchitis, decreased lung function, and premature death. PM contributes to haze and can harm the environment by changing the natural nutrient and chemical balance of the soil.
EPA Action
EPA scientists are conducting research to better understand which attributes of particulate matter cause ill health effects, who may be most susceptible to these effects, how particles form in the atmosphere, and what the contributions are from various sources in different regions of the country.
EPA's National Center for Environmental Assessment periodically evaluates the latest research concerning the public health and welfare effects of ozone and and publishes the most up-to-date findings in an assessment called the Integrated Science Assessment for Particulate Matter. his document provides the scientific basis for the establishment of the most current national air quality standards for PM. [See the history of PM for more detailed information]
Related Links
- Basic information about particulate matter
- Particulate matter research at EPA
- Particulate matter regulations
- National Ozone Air Quality Forecasts
- Clean Air Act