Final answer:
When the government issues marketable permits, each firm buys or sells permits until its marginal benefit from polluting equals the market price of a permit. Firms that have a low marginal cost of reducing pollution sell their permits, and firms that have a high marginal cost of reducing pollution buy permits.
Step-by-step explanation:
When the government issues marketable permits, each firm buys or sells permits until its marginal benefit from polluting equals the market price of a permit. This means that firms that have a low marginal cost of reducing pollution will sell their permits, while firms that have a high marginal cost of reducing pollution will buy permits. The goal is to align the economic incentives of firms with the goal of reducing pollution.