The influence of ammonia treatment at 800 o C on the catalytic activity of a viscose-based activated carbon cloth (ACC) was evaluated for the oxidative retention of H 2 S or SO 2 at room temperature. Change in the surface chemistry was observed by X-ray spectroscopy of nitrogen (N1s) and by temperature programmed desorption (TPD). Dynamic adsorption of H 2 S or SO 2 in moist air onto a packed bed of activated carbon cloth was monitored by measurement of the breakthrough curves at room temperature. ACC modified by ammonia showed noteworthy enhanced SO 2 and H 2 S loading relative to the untreated ACC. Improved SO 2 retention rate could be replicated several times after regeneration by washing at room temperature, in contrast to the case with H 2 S. The likely reasons for the behavior of H 2 S and SO 2 on the ammonia-treated ACC are discussed with reference to the recent literature.