The Clean Air Act is the law that defines EPA's responsibilities for protecting and improving the nation's air quality and the stratospheric ozone layer. The last major change in the law, the Clean Air Act Amendments of 1990, was enacted by Congress in 1990. Legislation passed since then has made several minor changes.
The Clean Air Act, like other laws enacted by Congress, was incorporated into the United States Code as Title 42, Chapter 85. The House of Representatives maintains a current version of the U.S. Code, which includes Clean Air Act changes enacted since 1990.
This site provides links to sections of the U.S. Code containing the amended text of the Clean Air Act. Section numbers in the U.S. Code are different than the Clean Air Act's section numbers. The table of contents below gives corresponding section numbers in the Clean Air Act (CAA) and the U.S. Code (USC). Another difference is that titles in the Clean Air Act correspond to subchapters in the U.S. Code.
Note: The 1990 Clean Air Act Amendments added a new title IV, relating to acid deposition control, without repealing the existing title IV, relating to noise pollution. The U.S. Code designates the original title IV, noise pollution, as subchapter IV and the new title IV, acid deposition control, as subchapter IV-A.
