Basics. Air scrubbers remove pollutants from air or smokestacks. Industrial scrubbers are divided into two categories, wet scrubbers and dry scrubbers.Both act in the smokestack and often use limestone, which chemically is a base, as a key ingredient because it reacts with sulfur dioxide and other acidic pollutants.asics. Air scrubbers remove pollutants from air or smokestacks. Industrial scrubbers are divided into two categories, wet scrubbers and dry scrubbers.