In the 1960s and 1970s, environmental protests helped the creation of acts like the Clean Air Act (1970), Wilderness Act (1965), and the National Trails Act (1968).
Clean Air Act:
"The Congress finds that---
...(2) that the growth in the amount and complexity of air pollution brought about by urbanization, industrial development, and the increasing use of motor vehicles, has resulted in mounting dangers to the public health and welfare, including injury to agricultural crops and livestock, damage to and the deterioration of property, and hazards to air and ground transportation; [and] (3) that air pollution prevention...and air pollution control at its source is the primary responsibility of States and local governments."
-Title 42, Chapter 85, Subchapter I, Part A, Sec 7401 of the United States Code
Clean Air Act. Code of Federal Regulations Vol. 42, 1970, sec. 85. Overview of the Clean Air Act and Air Pollution, United States Environmental Protection Agency, www.epa.gov/clean-air-act-overview. Accessed 12 Jan. 2018.