Best Available Control Technology (BACT)

The San Diego County Air Pollution Control District (District) New Source Review (NSR) Rules and Regulations apply to new, relocated or modified stationary sources.  The District NSR rules include:

• Rule 20.1 – NSR General Provisions
• Rule 20.2 – NSR – Non-Major Stationary Sources
• Rule 20.3 – NSR – Major Stationary Sources and PSD Stationary Sources
• Rule 20.4 – NSR – Portable Emission Units

Best Available Control Technology (BACT) is the cornerstone of the NSR program. Prior to the construction of a new facility or relocation of a facility/equipment which releases air pollutant emissions, District Rules and Regulations (Rules 10) specify that the equipment must obtain an Authority to Construct and be evaluated in accordance with applicable NSR rules (Rules 20.1-20.4). In general if such new, modified, replaced, or relocated equipment will result in an emission increase and has a potential to emit of 10 or more pounds per day of any of Volatile Organic Compounds (VOCs), Nitrogen Oxides (NOx), Sulfur Oxides (SOx) or Particulate Matter (PM10), the emission source must use BACT to reduce emissions.

The District has published a new "Revised BACT Guidance Document" in November 2023 to serve as a guideline to assist in BACT determinations for permitting of new, modified, replaced,or relocated equipment and processes.  The Revised BACT Guidance has updated information related to the use of the federal, state and local districts’ BACT Clearinghouses and Guidelines to determine BACT requirements.  The Revised BACT Guidance document can be accessed here.