The control of particulate matter (PM) in three lab-scale gas-phase bioreactors was studied. The three reactors include - compost-woodchip biofilter, polyurethane foam biotrickling filter and biotrickling filter packed with Pall-rings. Particle removal was dominated by Brownian diffusion for the smallest particles and by inertial compaction for the largest ones. The biofilter exhibited 100% removal at air contact times ranging from 20-81 sec. The results indicate that biofilters and biotrickling filters can be utilized successfully for particulate matter control.