Particulate matter

Particulate Matter (often abbreviated as PM) is a term used to describe the mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope.

Composition

Particulate matter can be made up of a number of components including nitrates, sulfates, organic chemicals, metals, soil or dust particles, and allergens (such as fragments of pollen or mold spores). The size of the particles is directly linked to their potential for causing health problems.

Health Effects

Health effects of particulate matter are related to the size of the particles, with smaller particles being able to penetrate deeper into the lungs and cause more health problems. Exposure to such particles can affect both your lungs and your heart, leading to serious health effects including premature death in people with heart or lung disease, nonfatal heart attacks, irregular heartbeat, aggravated asthma, decreased lung function, and increased respiratory symptoms.

Measurement

Particulate matter is measured using a variety of methods, most commonly through the use of a high-volume air sampler. This device draws air through a filter for a specified time, and the weight gain of the filter is used to calculate the concentration of particulate matter.

Regulation

In many countries, including the United States, particulate matter is regulated under air quality standards. These standards set limits on the concentration of particulate matter in the air, in order to protect human health and the environment.

See Also

• Air pollution
• Air Quality Index
• Environmental impact of the coal industry
• Health effects of air pollution

Particulate matter Resources
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