Method and apparatus for treating air containing hydrogen sulfide gas, volatile organic compounds, heavy metals and other mercaptans in order to reduce odor and corrosion related to wet wells, dry pits, grease traps and the like. The system comprises a first and second stage air treatment system. A vacuum pump in the primary (stage 2) treatment housing vacuums the contaminated air from the source and pumps the air through a set of diffusers into a treatment fluid wherein the air is then passed through a pair of porous plates and upward through a discharge pump and then into the atmosphere. Prior to treating the air in the primary housing, it is treated in a pretreatment dry air filter wherein the air is inlet into the pretreatment (stage 1) housing and then through a microfilter prior to being passed into the primary housing for further treatment.