All of the following are criteria pollutants except a. Lead b Mercury C. Ozone d. Carbon monoxide Nitrogen dioxide

The correct answer is b. Mercury.Criteria pollutants are a group of air pollutants that have been regulated by national environmental laws and regulations. The six criteria pollutants are:1. Lead (a)2. Ozone (c)3. Carbon monoxide (d)4. Nitrogen dioxide (e)5. Sulfur dioxide6. Particulate matterMercury is not considered a criteria pollutant, but it is a toxic air pollutant that is regulated under the Clean Air Act.