Filtration of Bioaerosols Using Fibrous Air Filter Media

Abstract

Airborne microorganisms cause many serious health problems. To control contamination and achieve acceptable indoor air quality (IAQ), it is necessary to study air filtration of bioaerosols systematically. The authors of this paper designed a test system to determine the removal efficiencies of fibrous air filter media for traditional nonbiological airborne particles (Dioctylphthalate, polystyrene latex, etc.) and bioaerosols. Escherichia coli and Serratia marcescens, generated by a Collison nebulizer, were used as two microbiological markers in evaluating the filtration efficiencies of air filter media. The removal efficiencies for challenge bioaerosols were compared with those of nonbiological particles of the same aerodynamic diameter. The efficiencies for the two kinds of aerosols were found to have similar characteristics, with the efficiency for the former generally found to be a little higher. A formula of a proposed filtration model for bioaerosols is suggested to roughly predict the filtration performance of the air filter medium. According to the experimental results, medium efficiency air filters are suitable for filtering biological particles in air-handling units. The filter efficiency measured with dioctylphthalate particles of 1 μm is useful for predicting the removal efficiency of bioaerosols for the filter medium.