PhMe-contg. air (up to 35 g/m(3)) was biofiltered through a mineral nutrient-covered coconut fibre bed under lab. conditions to remove the PhMe pollutant. The addn. of a com. nonionic surfactant to the bed at a concn. above the crit. micelle concn. (200-400 mg/L) resulted in increase in the biofiltration efficiency and bacteria content in the bed.