According to your textbook (p78):
In the scientific study The Benefits of the Clean Air Act, 1970 to 1990, the EPA determined that the Clean Air Act provided health, social, ecological, and economic benefits 42 times greater than its costs. In 2010 alone, estimated benefits exceeded costs at a ratio of 4 to 1.
In your opinion, why is the public generally unaware of these details? What are the difficulties with informing the public?