Air Pollution Control Program

Fine Particulate Matter 2.5

Particulate Matter (PM) | Health Effects of Particulate Matter | Forecasted Levels for PM 2.5

Particulate Matter
Particles in the air are a mixture of solids and liquid droplets that vary in size and are often referred to as "particulate matter." Some particles, those less than 10 micrometers in diameter, pose the greatest health concern because they can pass through the nose and throat and get deep into the lungs. Ten micrometers in diameter is just a fraction of the diameter of a single human hair. Particles larger than 10 micrometers do not usually reach your lungs, but they can irritate your eyes, nose and throat.

Fine Particulate
Particles that are less than 2.5 micrometers in diameter are called "fine" particles. These particles are so small they can be detected only with an electron microscope. Sources of fine particles include all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, and some industrial processes.

Coarse Dust Particulate
Particles between 2.5 and 10 micrometers in diameter are referred to as "coarse." Sources of coarse particles include crushing or grinding operations, and dust stirred up by vehicles traveling on roads.

Health Effects

Long-term Exposures

Short-term Exposures

Fine Particulate Matter 2.5 Ambient Air Monitoring Forecasts
Air pollution levels can vary throughout the day. Particle pollution, unlike ozone, can occur year-round.Your local air quality forecast can tell you when particle levels are high in your area. You can reduce your exposure to particles by

  1. Planning strenuous activity when particle levels are forecast to be lower
  2. Reducing the amount of time spent at vigorous activity,or
  3. Choosing a less strenuous activity (e.g., going for a walk instead of a jog).

When particle levels are high outdoors, they also can be high indoors. Certain filters and room air cleaners are available that can help reduce particles indoors. You also can reduce particles indoors by eliminating tobacco smoke and reducing your use of candles, wood-burning stoves and fireplaces.

Fine Particulate (PM 2.5) Standards

Fine Particulate (PM 2.5) Monitoring Plans

Fine Particulate (PM 2.5) Forecasts

For more information on Fine Particulate Matter contact the department's Air Pollution Control Program by email at or by phone at 573-751-7840.

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