Determination of water soluble trace gases in ambient air by condenser-type diffusion denuder coupled ion chromatography

An automated method is developed for simultaneous determination of water so luble eases at parts per trillion level in the environmental air. The metho d involves temperature-humidity control of sample air using a thermostated humidifier, collection of analyte gases by condenser-type effluent diffusio n denuder and subsequent effluent analysis by ion chromatography. The detec tion Limits (3 sigma) of the method for CH3COOH, HNO2 and SO2 gases are 0.0 22, 0.019 and 0.009 ppbv, respectively. The precisions range from 0.3 to 3. 0% RSD. The method has been successfully applied to urban air analysis and some results for nitrous acid and SOx in Seoul air are presented.