A new air-cleaning filter can get rid of all the harmful smoke substances in a room - where ten people are simultaneously smoking - in less than an hour, researchers say. The filter is coated with a manganese oxide-based nano-catalyst, which can be used in a smoking room to reduce and purify major harmful substances of cigarette smoke. The air cleaning equipment based on the newly-developed catalyst can purify over 80 per cent of the cigarette smoke within 30 minutes and 100 per cent of it within 1 hour in a 30 square meter smoking room, where 10 people are smoking simultaneously. Activated charcoal-based filters have been mostly used in a smoking room to remove gaseous materials in cigarette smoke. However, those filters are not effective in removing gaseous materials such as acetaldehyde, their absorption performance decreases fast in a closed facility such as a smoking room, and they need to be replaced at least every other week. The research team has developed a nano-catalyst filter by evenly coating a manganese oxide-based nano-catalyst powder onto a ceramic-based filter media. The nano-catalyst filter uses a technology that decomposes elements of cigarette smoke using oxygen radical, which is generated by decomposing ozone in the air on the surface of the manganese-oxide-based nano-catalyst filter. An evaluation test with total volatile organic compounds (TVOC), such as acetaldehyde, nicotine and tar, which account for the largest volume of gaseous materials in cigarette smoke, was conducted to evaluate the performance of the newly-developed catalyst. The results showed that the new catalyst decomposed over 98 per cent of the harmful substances. "The new air cleaning equipment based on a simple catalyst successfully processes and removes gaseous materials in cigarette smoke, which are not easily removed with the existing air cleaning technologies," said Dr Jongsoo Jurng of Korea Institute of Science and Technology (KSIT) in Seoul, who led the study with Dr Gwi-Nam. "If the new equipment can be simplified and is economically feasible, it will be an important tool for keeping smoking room pleasant and clean. Also, from the convergence perspective, the new nanometre catalyst filter can be integrated with other air cleaning products such as air purifiers and air conditioners," Jurng said.