Fine particle pollution is responsible for the death of 50,000 Americans every year.

Provo ranked sixth in the nation for the average daily levels of particle pollution.

He claims fine particle pollution is the greatest concern because of lung damage.

Coal-fired power plants are the largest source of so-called "fine particle pollution."

Among these pollutants, fine particle pollution is perhaps the most important as a cause of diesel's harmful health effects.

In some areas, residential wood smoke can be a significant source of exposure to fine particle pollution.

"Research is beginning to show that toxic particle pollution is worse for our health than we ever thought," he said.

In addition to engine emissions, particle pollution can come from other sources, depending on where you live.

Many sources contribute to levels of fine particle pollution and ozone that exceed national air quality standards.

Read more information about how air-borne particle pollution can affect health.