Abstract: An apparatus (10) for purifying polluted air consisting of particle phase pollutants and gaseous phase pollutants, the apparatus (10) comprising: a dust level sensor (23) to measure the amount of particle phase pollutants in the polluted air; a dust removal component (14) to remove the particle phase pollutants from the polluted air; a catalyst filtering core (17) to decompose the gaseous phase pollutants by chemical reaction; a valve (22) for selectively controlling a path of air flow within the apparatus (10) and is movable between an open position and closed position, the valve (22) being positioned downstream from the dust removal component (14); wherein if the amount of particle phase pollutants measured by the dust level sensor (23) is above a predetermined value, the valve (22) is moved to the open position to enable the air to bypass the catalyst filtering core (17); and if the amount of particle phase pollutants measured by the dust level sensor (23) is less than a predetermined value, the valve (22)