Air Pollution: Hearings Before a Subcommittee of the Committee on Interstate and Foreign Commerce, House of Representatives, Eighty-eighth Congress, First Session, on H.R. 4415, H.R. 4750, Bills to Improve, Strengthen, and Accelerate Programs for the Prevention and Abatement of Air Pollution; H.R. 3507, H.R. 4061, Bills to Accelerate, Extend, and Strengthen the Federal Air Pollution Control Program. March 18 and 19, 1963