Problem 55
Mercury, lead, and arsenic in the environment are major concerns. Identify the main source or sources of these pollutants.
Problem 56
What is the likelihood that hydrogen \(\left(\mathrm{H}_{2}\right)\) will become a widely used fuel and that the "hydrogen economy" will become a reality? In particular, what are the advantages and disadvantages of \(\mathrm{H}_{2}\) as a fuel? What would be necessary for a significant conversion to a "hydrogen economy"?
Problem 57
An understanding of most environmental issues requires one to consider a range of factors-economic, political, sociological, as well as scientific. Bearing this in mind, discuss each of the issues below. (a) Fracking is now in wide use, allowing us to access large quantities of natural gas. What are the positive factors that argue for continued and expanded use of this technique, and what are the concerns? (b) Most gasoline now sold contains ethanol. Is production of ethanol for use as a fuel a wise choice? List arguments for and against this policy. (c) Two types of vehicles, electric cars and cars using natural gas, are in early stages of development in the United States. Should their development be encouraged? What are the advantages and disadvantages to owning these cars now?
Problem 59
Which sulfur compounds are atmospheric pollutants? What is their origin? Describe steps being taken to prevent sulfur compounds from entering the atmosphere.
