What is Particulate Matter (PM)

• Airborne particulate matter (PM) consists of many different substances suspended in air in the form of particles (solids or liquid droplets) that vary widely in size.


• Particles less than 10 micrometers in diameter, that include both fine and coarse dust particles. These particles pose the greatest health concern because they can pass through the nose and throat and get into the lungs.

• Particles larger than 10 micrometers in diameter that are suspended in the air are referred to as total suspended particulates (TSP). These larger particles can cause irritation to the eyes, nose and throat in some people, but they are not likely to cause more serious problems since they do not get down into the lungs.

Health Effects of Dust and Smoke

• Dust and smoke may irritate healthy people's eyes, nose, throat, and lungs, and might cause more serious problems in sensitive populations.

• Because dust and smoke are mixtures of different chemicals with different sizes, not everyone will experience the same effects.

• In general, the long-term risk from short-term exposures to dust and smoke is low.

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