Which of the following statements pertaining to the Clean Air Act is incorrect?

Which of the following statements pertaining to the Clean Air Act is incorrect?
 
  a. The Clean Air Act, created by Congress in 1970 empowered the EPA to regulate the quality of air we breathe.
  b. The EPA established national ambient air-quality standards on a number of air contaminants called criteria air pollutants.
  c. Standards for six criteria air pollutants have been established to include carbon dioxide, ground-level ozone, mercury, nitrogen dioxide, pollen, and hydrogen peroxide.
  d. The primary standard identifies a contaminant concentration in the ambient air that protects human health.