Particulate Matter (PM) Air Pollution


Particulate matter pollution consists of very small liquid and solid particles floating in the air. Of greatest concern to public health are the particles small enough to be inhaled into the deepest parts of the lung. These particles are less than 10 microns in diameter (about 1/7th the thickness of a human hair) and are known as PM10. This includes fine particulate matter known as PM2.5 PM10 is a major component of air pollution that threatens both our health and our environment.


In the western United States, there are sources of PM10 in both urban and rural areas. Major sources include:
  • Motor vehicles
  • Wood burning stoves and fireplaces
  • Dust from construction, landfills, and agriculture
  • Wildfires and brush/waste burning
  • Industrial sources
  • Windblown dust from open lands

PM10 is a mixture of materials that can include smoke, soot, dust, salts, acids, and metals. Particulate matter also forms when gases emitted from motor vehicles and industry undergoes chemical reactions in the atmosphere.


PM10 is often responsible for much of the haze that we think of as smog. This is a problem in our cities, rural areas, and pristine areas-such as national parks and forests.


The United States Environmental Protection Agency has set air quality standards for PM10, Based on health research, these identify acceptable levels of PM10. Currently, these standards are violated in many parts of the western United States.

Air quality agencies in several states have developed, or are now developing, air quality plans to bring PM10 concentrations down to healthful levels. These plans include a variety of programs to reduce emissions, including:

  • Dust control for roads, construction, and landfills
  • Landscaping, barriers, and fencing to reduce windblown dust
  • Programs to reduce emissions from wood stoves and fireplaces
  • Cleaner-burning gasoline and diesel fuel
  • Emission control devices for motor vehicles
  • Controls for industrial facilities


Here are a few things individuals, businesses, and other organizations can do immediately to reduce the threat of PM10:

  • Reduce travel on days with poor air quality
  • Avoid vigorous physical activity on days that have poor air quality
  • Avoid using your wood stove and fireplace on days that have poor air quality
  • Avoid using leaf blowers and other dust-producing equipment
  • Drive slowly on unpaved roads and other dirt surfaces
  • Get involved with air quality improvement programs in your community

If you own and operate an industrial source of PM10, comply with local rules that apply to your operation. Work with local agencies to develop strategies that will further reduce PM10 emissions.

Information obtained from the Best Available Control Measure (BACM) Working Group, a multi-agency group comprised of local, state, and federal air quality and public health protection agencies from the states of Arizona, California, and Nevada.