What is the Clean Air Act designed to place restrictions on?

The Clean Air Act designed to put restrictions and reduce air pollution in the United States.

Explanation:

The Clean Air Act intended to protect human health and the environment from air pollution. The pollution increased because of energy generation, industrial development, and motor vehicles. The Clean Air Act first implemented in America in 1970 and then amended in 1977 and 1990. It was an effort to reduce air pollution by the United States federal government. State and local governments also control and enforce Clean Air Act laws.

the use of email to replace slower surface mail.

a phrase from a poem by ralph waldo emerson about the battle of lexington and concord. emerson's words read, “here once the embattled farmers stood / and fired the shot heard round the world.”