This paper investigates the effectiveness of a Purging System in a high-rise office building in Singapore with the aim of improving indoor air quality. The study initially adopts a continuous monitoring concept to investigate the impact of a daily purging operation on pollutant concentration levels at the low, middle and high floors of the office building. Pollutants investigated include formaldehyde, carbon dioxide, carbon monoxide and total volatile organic compounds (TVOC). This is then followed by purging experiments using sulphur hexafluoride in three different configurations to obtain various ventilation parameters. Finally, Computational Fluid Dynamics (CFD) simulations using FLUENT software are used to corroborate the results. It is shown that purging is effective in reducing indoor TVOC and carbon dioxide concentration, and should be executed at times when the lowest carbon monoxide concentration is registered outdoors. The minimum duration of purging is observed to be 12 minutes, even with a purging fan having a capacity of six air-change-per-hour.