ENV-05-193 Assessment of Source-Specific Regional Haze BART

Description:

Best Available Retrofit Technology (BART) is part of the Clean Air Act as a requirement related to visibility that applies to existing stationary sources. Sources eligible for BART are those from 26 source categories with a potential to emit over 250 tons per year of any air pollutant, and placed into operation between August 1962 and August 1977. This period of applicability stems from the U.S. EPA’s adoption of the Prevention of Significant Deterioration (PSD) rules in 1977, which included requirements for new sources to evaluate and mitigate visibility impacts in Class I areas. Thus, sources built before the PSD rules that had escaped this analysis are possibly subject to BART. The U.S. EPA adopted the first BART requirements in 1980 (45 Fed. Reg. 80084) to address visibility impairment that was “reasonably attributable” (RA) to a single stationary source or small group of stationary sources in “close proximity” to the affected Class I area. At that time, little was known about regional haze and its effect on visibility of sources distant from Class I areas. The goal of the visibility program through the Regional Haze Rule is to achieve “natural conditions” in parks and wilderness areas by 2064. States and tribes can choose strategies to reach this goal, and BART is one required part of the visibility program that is applicable for a required milestone of progress by the year 2018. BART applies to a certain subset of existing sources that have previously been grandfathered from emission controls. The reductions from BART must, in conjunction with other emission controls, enable the states to achieve the required visibility improvements associated with the first RHR compliance period, which ends in 2018. As discussed below, the assumptions made in the definition of natural background have implications for the adequacy of the application of proposed BART controls. Section 309 of the Regional Haze Rule allows states involved in the Grand Canyon Visibility Transport Commission (GCVTC) to take an alternate approach to BART. This approach to date has involved focusing primarily on sulfur dioxide (SO2) emissions, and setting voluntary emission reduction targets “SO2 milestones”, instead of requiring BART. However, these milestones must be “better than BART”; that is, provide greater emission reductions than would be achieved by the application of BART. If the SO2 milestones are not achieved, then a backstop emissions trading program would go into effect to make sure the milestones are being met. A recent proposed rule for alternative trading plans in lieu of BART would revise the Section 309 procedure, allow participation by all of the GCVTC states and tribes, and consider NOx and PM emissions as well as SO2 emissions in the alternative plan. This plan would also need to consider additional emission reductions through the year 2040.