Deodorization of polluted air is captured and neutralized by successive chemical cleanings in the deodorization towers which neutralize the odours caused by bacteriological fermentation. Our system TRSMEDOR consisting of our analyzer, supervisor with our own operation software, VISTACHROM, and multiplexer, analyses H2S concentrations and can pilot the adjunction of calcium nitrates.The process allows to the bacteria to have an oxygen reserve and therefore to stop the sulphate transformation into sulphides and H2S.