What is an air pollution control device used in vapor recovery?

• A. An air filter
• B. A chemical scrubber
• C. A vapor recovery unit (VRU)
• D. A thermal oxidizer

Answer: (C)

A vapor recovery unit (VRU) is specifically designed to capture and recover vapors that would otherwise be released into the atmosphere during processes such as storage or transfer of liquid fuels. This technology is essential for minimizing air pollution and ensuring that volatile organic compounds (VOCs) are effectively managed.

VRUs work by collecting vapors from tanks or pipelines and either returning them to storage tanks or processing them for various uses, thereby reducing the emissions that contribute to air pollution. This not only helps in complying with environmental regulations but also contributes to the conservation of resources since recovered vapors can often be reintegrated into the fuel supply or utilized in other applications.

In contrast, while air filters and chemical scrubbers can be important for different aspects of air quality control, they serve different functions and may not be specifically designed for vapor recovery as the VRU is. A thermal oxidizer, meanwhile, is utilized to destroy various types of pollutants and may not focus solely on the recovery aspect associated with vapors emitted from liquids. Thus, a VRU stands out as the primary device dedicated to the recovery of vapors, making it the correct answer.