Which act did Congress enact to protect public health and welfare from various air pollution types?

The Clean Air Act is the crucial piece of legislation that was enacted by Congress to address and mitigate the various types of air pollution affecting public health and the environment. This act establishes comprehensive federal and state regulations aimed at controlling air emissions from both stationary and mobile sources. It empowers the Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards (NAAQS) to protect public health and the environment from harmful pollutants.

The act has undergone several amendments since its original passage, allowing for more stringent standards and expanding the scope of pollutants regulated. Its significance lies in its systematic approach to improving air quality and ensuring that all Americans have the right to breathe clean air, emphasizing the protection of vulnerable populations such as children and the elderly.

While the other mentioned options might refer to environmental or pollution control efforts, none specifically focuses on air pollution with the same level of authority and comprehensive scope as the Clean Air Act does. Thus, the Clean Air Act stands out as the correct answer.