Numerical Simulation of Atmospheric O 3 at Yosu, Korea and Comparison with Measured Data Akira Kondo, (1) Sang Deug Lee (2) , Keiichi Yoshimura (1) , Katsuhito Yamaguchi, (1) Akikazu Kaga (1) (1) Dep. of Environmental Eng., Osaka University, Yamada-oka 2-1 Suita Osaka 565-0871, Japan E-mail: kondo@env.eng.osaka-u.ac.jp (2) Dep. of Environmental Eng., Mokpo National University, 61 Dorim-ri, Chungkye- myun, Muan-gun, Chonnam, 534-729, Korea E-mail: leesang@chungkye.mokpo.ac.kr Abstract The atmospheric pollution distribution in the industrial area of Yosu in Korea is calculated using numerical model and the model is validated by comparing the calculations with observed data. The emission of NO x and SO x was estimated for 6 sources, and the emission amount of HC was estimated for 9 anthropogenic sources. The calculated wind speed, wind direction and temperature agreed well with the observed data at two observatories, and the calculated concentration of NO, NO 2 , O 3 and SO 2 were also reasonable for 5 monitoring stations. The validity of the model is evaluated using 3 indexes of the EPA, and the model is found to be valid and accurate. Key words: Photochemical oxidant, nitricdioxide, sulfurdioxide, diffusion model, emission 1. Introduction Although several atmospheric pollutant concentration simulations have been per-