The objective of this study is to analyze the removal characteristics and distribution of indoor air pollutants by a room air cleaner. A pollutant removal effect according to room volume and measurement point was evaluated in an indoor room. A series of filtration efficiency tests were performed on only the electrostatic precipitator of the room air cleaner. The measurements of filter efficiency and pressure drop across the electrostatic precipitator were made using an ASHRAE 52.1-1992 filter test system and an opacity meter to measure the particle concentration upstream and downstream of the test filter. Also the performance of the air cleaner in the room was evaluated by examining tobacco smoke particle concentration. The size distribution of the tobacco smoke particles was 1.27 μm in mass median diameter and a geometric standard deviation of 1.313 μm. The efficiency of the electrostatic filter was measured as 78.6% with dust particles of 1.96 μm in mass median diameter and 1.5m/s face velocity. The tobacco smoke particle concentration as a function of time decayed exponentially. The contaminant removal effect was increased when increasing the effective clean air exchange rate (ηQ/V), which is 0.0780 min.1 for 51 m3 room and 0.0235 min^(-1) for 149 m3 room. This study clearly shows that a room air cleaner with an electrostatic precipitator is effective in removing tobacco smoke particles. The removal characteristics and distribution of indoor air pollutants in other rooms is predicted based on empirical modeling.