Scrubbers are air pollution control devices that play a crucial role in removing pollutants from industrial exhaust streams:
(A) Particulate SO2 - Incorrect: SO2 exists as a gas at normal conditions, not as particulate matter.
(B) Liquid SO2 - Incorrect: Sulfur dioxide is only liquid under high pressure or low temperature conditions, not in typical industrial emissions.
(C) Gaseous SO2 - Correct: Scrubbers are specifically designed to remove gaseous sulfur dioxide (SO2) from flue gases through chemical reactions with alkaline slurries, typically forming calcium sulfite or sulfate.
(D) Liquid SO3 - Incorrect: Sulfur trioxide (SO3) typically reacts with water vapor to form sulfuric acid mist, not remaining as a liquid in exhaust streams.
The correct answer is (C) Gaseous SO2, as scrubbers primarily target this major air pollutant from combustion processes through wet or dry scrubbing technologies.