We have simulated inorganic phase partitioning in forward, stable (solid + liquid) mode using the thermodynamic equilibrium model ISOROPIA-II. Observations of inorganic components concentrations in aerosols including precursor gases (Na+, SO42-, NH4-, NH₃, NO-, HNO₃, Cl-, HCl, Ca2+, K2+, Mg2+), ambient temperature and relative humidity (RH), measured at the Bulkwang-dong in Seoul were used as input data. In the case of winter, the concentrations of SO42- and NH₃ were lower than those of summer data, while the concentration NO3- and NH4+ were higher in winter data. The average winter temperature and RH were -3.45 ℃ (-18.5 ~ 11 ℃) and 0.58 (0.25 ~ 0.95), and those of summer were 23.07 ℃ (15.5 ~ 31.4 ℃) and 0.73 (0.38 ~ 0.98), respectively. The ISOROPIA-II prediction results performed in forward, stable mode were well predicted for both NO3- (R² = 0.9919) and NH₃ (R² = 0.9544) in winter. In the case of summer, NH₃ (R² = 0.9403) was well predicted, while NO3- (R² = 0.8549) was lower than in winter. When the relative humidity was 0.60 or more, both winter and summer showed a high prediction of a correlation of 0.95 or more. However, when the relative humidity was 0.60 or less, the correlation of NO3- in winter reached 0.98, that in summer dropped to 0.57. Because the relative humidity and temperature show opposite tendencies, we conducted temperature sensitivity test. As a result, the correlation coefficient decreased as the temperature increased. When the temperature of winter was increased by 20 ℃, the correlation coefficient of NO3- fell from 0.9919 to 0.7656. When the equilibrium constant of the thermodynamic equilibrium model was changed, the correlation coefficient of NO3- increased as the equilibrium constant of NO3- increased. According to the NHx region, aerosols in Bulgwang-dong are all ammonia-rich in summer, but in winter, they were divided into ammonia-rich and ammonia-poor. Predictions from the thermodynamic equilibrium model ISORROPIA-II show that aerosols have a summer average pH of 2.6 (0.9 to 3.6) and a winter average of 3.1 (-1.2 to 4.7). Both summer and winter showed acidic, and in the case of winter, the pH of aerosol differed sharply depending on the excess NHx when ammonia-poor condition.