If a factory was built in 1990 and emits air pollution, what type of pollution control devices are required?

The correct answer is BACT, which stands for Best Available Control Technology. This approach is applied specifically to major sources of air pollution to ensure that operations implement the most effective technological solutions available to minimize emissions. Since the factory was built in 1990, it would likely fall under regulations that mandate the use of BACT to address the emissions generated by the facility.

The rationale behind requiring BACT is to utilize advanced technologies that can dramatically reduce the pollution emitted, thus safeguarding air quality and public health. This is particularly significant for older factories that may have been constructed under less stringent regulatory standards, requiring them to upgrade their pollution control measures.

RACT, which stands for Reasonably Available Control Technology, is generally tailored for existing sources of pollution that are less significant in scale, focusing on achieving a balance between the cost of control and the reduction of emissions. BPCT pertains to Best Professional Control Technology, which is not commonly referenced in direct pollution control contexts. MACT, or Maximum Achievable Control Technology, relates to hazardous air pollutants and sets standards for emission limits, but would not be directly applicable to general air pollution from a factory built in 1990 unless it specifically involved hazardous pollutants for which MACT standards existed.