EPA has set national ambient air quality standards for:

A) chlorofluorocarbons.
B) sulfur oxide.
C) carbon dioxide.
D) methane.

National Ambient Air Quality Standards

Regulations established by the United States Environmental Protection Agency intended to limit pollution and protect public health and the environment.

EPA

The Environmental Protection Agency, a U.S. governmental agency tasked with protecting human health and the environment through regulations and enforcement.

Sulfur Oxide

A group of chemical compounds that are a combination of sulfur and oxygen, often associated with air pollution and acid rain.