Particle Pollution Basics

Particle pollution is simply defined as solid particles or liquid droplets that are suspended in air. There are two size ranges for particle pollution that are a concern in Wisconsin; coarse particles (PM10) that have an aerodynamic diameter of 10 microns or less, and fine particles (PM2.5) that have an aerodynamic diameter of 2.5 microns or less.

Fine particles (PM2.5) may be emitted directly into the atmosphere but are more commonly created by reactions of other pollutants. Fine particles in the air may be consist of hundreds of different chemicals, but sulfur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOC), and ammonia are the basic building blocks for most of the fine particles or PM2.5 in Wisconsin. Sources of direct PM2.5 emissions include forest fires and wood stoves. Sources of the precursor pollutants that chemically react to form PM2.5 include power plants, industries, and automobiles. Wind can carry fine-particles hundreds of miles from its source. In Wisconsin, PM2.5 levels typically peak in winter but concentrations can also be high in summer.

Coarse particles (PM10) usually result from some type of mechanical action such as crushing or grinding, or from wind-blown dust. Sources of coarse particles include roadways and dusty industries. Coarse particles are typically not transported great distances as are fine particles.

To reduce particle pollution, the state and federal regulations target NOx and SO2 emissions from power plants and industrial combustion sources. Additionally, mobile source control programs such low-emission vehicles and cleaner gasoline help reduce VOC and NOx emissions from mobile sources. More information on particle pollution can be found at EPA’s particle pollution website [exit DNR].

Health and Environmental Effects

Both coarse and fine particles pose health problems, because they can bypass the body’s natural defense mechanisms and affect both your lungs and your heart. Particles can become lodged in your lungs, and very fine particles may even get into your bloodstream.

Health Effects

Scientific studies have linked particle pollution exposure to a variety of health problems such as:

• increased coughing, or difficulty breathing,
• decreased ability of the lung to transfer oxygen to the lung
• aggravated asthma,
• chronic bronchitis,
• irregular heartbeat
• nonfatal heart attacks,
• premature death in people with heart or lung disease.

People with heart or lung diseases, children, and older adults, are the most likely to be affected by particle pollution exposure. However, even if you are healthy, you may experience temporary symptoms from exposure to elevated levels of particle pollution. For more information about asthma, visit Air Quality Information for Health Professionals and EPA’s asthma website [exit DNR].

Environmental Effects

Fine-particles scatter light and are the major cause of reduced visibility in the United States. Many fine-particles are also acidic, causing acid rain and making lakes and streams acidic. Deposition of nitrogen-containing particles may change the nutrient balance in lakes and rivers, affecting the diversity of ecosystems or damaging forests or crops. In addition, particle pollution can damage statues, monuments and buildings made of stone and other materials.

For more information

• Visibility protection and haze
• EPA’s visibility web site [exit DNR].
• EPA’s acid rain website [exit DNR]

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