As long as the party has the allowances on account that they desire to trade, the EPA processes the transaction. This simplicity has kept transaction costs low and helped to create efficiencies that might otherwise not exist. The simplicity of the market has also attracted third parties, such as brokers and independent trading firms. These parties have helped to increase market liquidity. The Acid Rain program allows sources the needed flexibility to choose the desired compliance methodology.
Sources can install equipment, reduce usage, or buy allowances, for example, in any combination.
The same flexibility should be built into any trading programs for NOx or greenhouse gas emissions. For greenhouse gas emissions this would include the recognition of Joint Implementation projects entered into with non-Annex I nations. Developing nations are the source of some of the most cost-effective greenhouse gas reduction and sequestration projects worldwide. For NOx, this may mean allowing inter-sector trading. Certifiable Reductions .