Columbia subject headings:
Air--Pollution--United States.
Ozone--Environmental aspects--United States.
United States. Clean Air Act.
Harvard subject headings:
Air--Pollution--Measurement--Standards.
Air--Pollution--United States
Atmospheric ozone--Government policy--United States.
Atmospheric ozone--Reduction.
Ozone--Environmental aspects--United States.
Ozone--Physiological effect
United States. Clean Air Act
Princeton subject headings:
Air--Pollution--United States.
Ozone--Environmental aspects--United States.
United States. Clean Air Act