| With the ion chromatographic method, the water-soluble ion concentrations of Cl-, NO-3, SO2-4, CH3SO-3 (MSA), Na+, K+, NH+4, Mg2+ and Ca2 in the atmospheric aerosol over the East China Sea in winter 2009 was determined and the sources of these ions was investigated through correlation analysis by SPSS(statistical package for social sciences) software. The results indicated that the concentrations of secondary ions in aerosol were the highest (non-sea-salt sulfates nss-SO2-4，NO-3，NH+4), accounting for 78.4% of total determining ions. The calculation results of equivalent concentration of anions and cations showed that the acid ions of aerosol were neutralized inadequately. The stoichiometry of NH+4 in different compounds showed that NH4HSO4 was the main binding form of NH+4 and SO2-4 in the aerosol. The concentration of methanesulfonic acid (MSA) was low, and the average value was (0.0088±0.0037) μg·m-3. According to calculation, the contribution of sea-salt sulfates was 4.5% to total sulfates, and that of biogenous sulfates was 1.4% to non-sea-salt sulfate（nss-SO2-4）, showing that human input was the main source of sulfates in aerosol over the East China Sea. In addition, nss-SO2-4/NO-3 in the aerosol was 1.08, reflecting that China's energy structure adjustment played an important role in recent years. |
