sentences:  Though capable of some incidental control of volatile organic compounds 
  (VOC), generally venturi scrubbers are limited to control PM (particulate matter) and high solubility gases ("EPA, 1992; EPA, 1996").The primary maintenance problem for venturi scrubbers is wear, or abrasion, of the scrubber shell because of high gas velocities.Gas velocities in the throat can reach speeds of 430 km/h (270 mph).