Particulate Matter (PM2.5) Health Advisories Issued for National Parks
Today – Tuesday, November 24, 2009
Currently, no national parks are issuing particulate matter (PM2.5) health advisories.
Particulate matter less than 2.5 micrometers in diameter is called PM2.5 or fine particles. Sources of fine particles include all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning, and some industrial processes. High concentrations of PM2.5 can cause inflammation and irritation of the respiratory tract and aggravate heart or lung disease. PM2.5 concentrations have approached and exceeded the national health standards at several National Park Service areas. Because of possible health effects and concern for the health and safety of visitors and employees, the National Park Service developed guidance for PM2.5 advisory programs in National Park Service units where levels approach or exceed the PM2.5 health standard (40 micrograms per cubic meter, 24-hour average). These parks include Grand Canyon, Great Smoky Mountains, and Mammoth Cave National Parks. Whenever PM2.5 levels exceed or are predicted to exceed this health standard at these parks, the park personnel post health advisories cautioning visitors of the potential health risks associated with exposures to elevated levels.
National Park Service PM2.5 Health Advisory Levels
| PM2.5 Value | Descriptor | Precautions |
|---|---|---|
| 0 – 15 µg/m³ | Good | None |
| >15 - 40 µg/m³ | Moderate | Unusually sensitive people should consider reducing prolonged or heavy exertion |
| >40 - 65 µg/m³ | Unhealthy for Sensitive Groups |
People with heart or lung disease, older adults, and children should reduce prolonged or heavy exertion |
| >65 - 150 µg/m³ | Unhealthy for the General Public | People with heart or lung disease, older adults, and children should avoid prolonged or heavy exertion; everyone else should reduce prolonged or heavy exertion |
| >150 - 250 µg/m³ | Very Unhealthy | People with heart or lung disease, older adults, and children should avoid all physical activity outdoors; everyone else should avoid prolonged or heavy exertion |