See | 23 41 00 for HVAC-type particulate air filtration. 23 42 00 for gas-phase air filtration. 43 11 00 for gas fans, blowers, pumps, and boosters. 43 12 00 for gas compressors. 43 31 00 for gas and liquid purification filtration equipment. 44 11 00 for air pollution control equipment. |