In this work, the removal of monochlorobenzene (CB) vapors from air was studied, for the first time, in a non-inoculated, laboratory-scale, aerobic biofilter. The influence of three parameters on the bioprocess has been evaluated: the rate of nitrogen supplied to the bed, the inlet concentration of CB, and the flow rate. The CB inlet concentration was varied between 0.3 and 3.2 g m(-3), at a constant flow rate of 1.0 m(3) h(-1). Removal rates of greater than 90% were achieved for CB inlet concentrations of up to 1.2 g m(-3). Then the flow rate was varied from 0.5 to 3.0 m(3) h(-1) with a constant inlet concentration (1.2 g m(-3)). Maximum elimination capacities (70 g m(-3) h(-1)) were reached for contact times of greater than 60s. The study of varying flow rates also permitted evaluation of a first order macrokinetic constant (1.1 x 10(-2) s(-1)) for the CB biodegradation. Finally, the optimum nitrogen input value was found to lie between 0.3 and 0.4 g Nh(-1) and gave rise to elimination capacities as high as 70 g m(-3) h(-1) for an inlet load of near 80 g m(-3) h(-1). (C) 2003 Society of Chemical Industry.