Impacts of air pollution on national park units : hearing before the Subcommittee on National Parks and Recreation of the Committee on Interior and Insular Affairs, House of Representatives, Ninety-ninth Congress, first session ... hearings held in Washington, DC, May 20 and 21, 1985.
United States.Congress.House.Committee on Interior and Insular Affairs.Subcommittee on National Parks and Recreation.
Washington [D.C.] : U.S.G.P.O.,
1986.
"Serial no. 99-10."
Air
National parks and reserves