Region 2 has 11 Class I wilderness areas, totaling 2,828,579 acres. There are also 23 Class II wilderness areas in the region. The region assesses current pollution impacts and predicts future impacts to air quality and air quality related values (AQRVs) in both Class I and Class II wilderness areas. This may include identifying and remedying impairment from existing sources, as well as modeling future impairment from potential sources. The major pollutants of concern in the region are particulate matter (PM-10 and PM-2.5), sulfur dioxide and sulfate (SO2 and SO4), and nitrogen oxides and nitrate (NOx and NO3). Ozone has not been shown to be a concern in the Rocky Mountain Region at this time.