The work presents the results of experimental studies on the air purification efficiency after accelerated composting of a mixture of cattle manure and straw in a chamber-type biofermenter. The operation of an experimental plant that simulates this process is described. A process optimization criterion has been established, its values have been determined for each of the pollutants – ammonia and hydrogen sulfide. The maximum purification efficiency for ammonia is 92%, achieved at 47% moisture content of the filtering material and 58% compost weight parts at 30°C. For hydrogen sulfide, the maximum purification efficiency is 95%, achieved at 50% moisture content of the filtering material and 52% compost weight part at 28°C