Final answer:
Transferable discharge permits are primarily utilized for air pollution control in power-generating companies, especially to limit sulfur dioxide emissions associated with acid rain.
Step-by-step explanation:
Transferable discharge permits are most often used for air pollution from power-generating companies. An example of this application is the amendment of the Clean Air Act in 1990, where the U.S. government implemented a marketable permit program to reduce sulfur dioxide emissions from electricity-generating plants, particularly coal-burning plants. These marketable permits allowed the firms to emit a certain amount of pollution, which could be bought or sold, and were designed to shrink over time, thereby reducing the allowed amount of emissions.