Columbia subject headings:
Air--Pollution.
Atmospheric carbon dioxide.
Environmental policy--United States.
Greenhouse gases.
United States. Environmental Protection Agency.
Harvard subject headings:
Air--Pollution
Atmospheric carbon dioxide.
Environmental policy--United States
Greenhouse gases.
United States. Environmental Protection Agency
Princeton subject headings:
Air--Pollution.
Atmospheric carbon dioxide.
Environmental policy--United States.
Greenhouse gases.
United States. Environmental Protection Agency