Columbia subject headings:
Acid rain--United States.
Air--Pollution--United States.
Environmental policy--United States.
Nitrogen oxides--Environmental aspects--United States.
Sulfur dioxide--Environmental aspects--United States.
Harvard subject headings:
Acid precipitation (Meteorology)
Acid rain.
Air--Pollution--Government policy--United States
Nitrogen oxides--Environmental aspects
Sulfur dioxide--Environmental aspects.
Princeton subject headings:
Acid rain--United States.
Air--Pollution--United States.
Environmental policy--United States.
Nitrogen oxides--Environmental aspects--United States.
Sulfur dioxide--Environmental aspects--United States.