Region 8

Air Planning

EPA's State Program Support Unit has responsibility for technical review of State Implementation Plans (SIPs). Goals include providing guidance to the states in preparing plans for cleaning the air within their borders; overseeing and relieving the impact air pollution may have on 39 national parks, wilderness areas and tribal areas within the six states that comprise Region 8; performing mathematical modeling and meteorological assessments to determine the fate and transport of air pollutants and the health or ecological effects of air pollution within Region 8; assuring that high quality emission inventories are conducted within each State; conducting assessments and studies of critical regional air issues such as the Denver Brown Cloud; and having an assertive role in the reduction of regional haze, visibility, and tribal issues.

Nonattainment Areas and Areas with a History of Air Pollution

When an area does not meet the air quality standard, it may be subject to formal rule making process which designates it nonattainment. Region 8 has a number of nonattainment areas for various pollutants:

PM10 particles are particles with diameters between 2.5 and 10 micrometers and are known as "coarse" particles. PM10 levels must be below 150 micro-grams per cubic meter (µg/m3)of air for 24 hours and below 50 µg/m3 for the year for an area to be considered in attainment for particulate matter.

Montana: Butte, Columbia Falls, Kalispell, Libby, Missoula, Thompson Falls, and Whitefish
Tribal: Lame Deer, Polson, and Ronan, Montana
Utah: Salt Lake County, Utah County and Ogden
Wyoming: Sheridan

Currently, all states in Region 8, with the exception of the Denver, Colorado metropolitan area, are in attainment of the 8-hour and the 1-hour Ozone standard as applicable. On March 12, 2008, EPA strengthened the National Ozone standard. For more information, please go to EPA's Ground-level Ozone: Regulatory Actions page.

Sulfur Dioxide
Region 8 has four areas where in the past sulfur dioxide concentrations have been frequently higher than the standard. Two of the areas are located in Montana. One area is located in Laurel, MT near the city of Billings, MT. View a graph showing sulfur dioxide (SO2) concentrations in the Billings area. The second area in Montana is East Helena, MT. Both are non-attainment areas for SO2. The other two non-attainment areas for SO2 are Salt Lake County and a portion of Tooele County in Utah.