In which year did the Clean Air Act direct the EPA to establish requirements for air quality?

The Clean Air Act was significantly amended in 1990 to address various air quality issues and establish requirements for the regulation of air pollutants. One of the key components of these amendments was the direct instruction to the Environmental Protection Agency (EPA) to develop and implement regulations that would help improve air quality across the United States. This initiative included setting National Ambient Air Quality Standards (NAAQS) for common air pollutants, ensuring that both public health and the environment were protected from harmful effects.

The amendments introduced in 1990 represented a major shift in how air quality issues were approached, pushing for a more comprehensive and stringent regulatory framework. This framework included provisions for state implementation plans, enforcement measures, and mechanisms for monitoring air quality, thereby directly addressing the issue of air quality management established by the Clean Air Act.

The other years listed do not correspond to such a pivotal moment in air quality legislation. While the original Clean Air Act was first passed in 1963, and there were previous amendments, it was the 1990 revision that truly focused on establishing clear requirements for air quality standards and regulatory processes.