Air quality control agencies determine the pollution control technologies, emission limits and other requirements applicable to stationary sources, such as power plants, through the permitting process. All major facilities, ranging from power plants to refineries, are required under the Clean Air Act to obtain a permit. There are two main types of air pollution permits: preconstruction permits and operating permits. Sources must apply for preconstruction permits before building a new facility, or beginning major modifications to an existing facility, if the facility is expected to increase its emissions of regulated air pollutants by significant amounts. Preconstruction permitting is undertaken through the “New Source Review” process, to determine appropriate air pollution controls, generally the Best Available Control Technology.
Once a facility begins operation, it receives an operating permit, or Title V permit, which outlines all of the pollution control standards the facility must follow. This includes important information such as pollutant monitoring, recordkeeping requirements, and emission limits, which help air quality agencies ensure that the facility complies with the relevant pollution control standards. The permitting process also provides the public with opportunities to review and comment on draft pollution control technologies and standards that will apply to the facility.