Studies were conducted by employing a new generation lamellar structure laboratory air purification device -a biofilter, capable of purifying airflow, polluted with gaseous pollutants. The internal structure of the biofilter is unique in that the bioload, upon which microorganisms dwell and propagate, is fitted onto uprightly arranged wavy lamellas -a layout that creates a capillary moistening effect. Thermally treated birch wood fibers and non-woven caulked materials were used as the bioload in order to increase durability of the load. This paper discusses the results of studies, performed to determine the efficiency of acetone, xylene and ammonia's biological breakdown processes. The conducted research revealed high efficiency of biological breakdown processes. With the acetone fumes concentration of 0,3 g m -3 running through the biofilter load at the velocity of 0,08 m s -1 and with the number of self-contained microorganisms 1,28·10 10 CFU/cm 2 , the biodegradation efficiency of the contaminant was 94%, with the xylene fumes concentration of 0,3 g m -3 running through the biofilter load and the number of self-contained microorganisms 2,45·10 8 cfu/cm 2 , the efficiency was 87%, and running 0,3 g m -3 concentration of ammonia fumes the efficiency was 88% with the number of self-contained microorganisms of 4,4·10 8 CFU/cm 2 . Using wavy lamellas with fastened load allows a longer contact time between the pollutant and the bioload compared to flat lamellas.