Installation of high-performance filter systems in restrooms is necessary because of bacterial and odor gas contamination from feces. Presented herein is a sterilizing deodorizing filter (SDF) consisting of a negative air ion (NA!) filter and an alumina support catalyst (ASC) of copper and phosphoric acid. The Escherichia coli removal of the SDF was evaluated with three DC voltages (-3,-5, and -7 kV) at the space velocities of 1.6 x 10(4), 2.8 x 10(4), and 5.6 x 10(4) h(-1). The performance of the SDF peaked at 99.9% at the high voltage of -7 kV and the high space velocity of 6 x 10(4) h(-1) for bacteria removal. In addition, the average bacteria removal efficiency of the SDF was 1.2 times higher than the NAI filter alone at the space velocity of 5.6 x 10(4) h(-1). The gas removal performance of the NAI filter remained the same regardless of the duration of the experiment, but was very low at 16.7% for ammonia and 12.7% for hydrogen sulfide. The SDF and ASC filter maintained the removal rate of 100% for the first 15 min of the experiment. However, after 300 min, the gas removal efficiencies of the former were higher than those of the latter by 28.8% and 15% for ammonia and hydrogen sulfide, respectively. The reason for this phenomenon is that the ASC improves performance by increasing contact with the NAIs as a result of gas adsorption and gas removal. (C) 2013 Elsevier Ltd. All rights reserved.