The total suspended particulate (TSP) samples in aerosol were collected over the Bohai Sea (BS) and the North Yellow Sea (NYS) during Autumn 2010 to determine the concentration of main water-soluble cations (Na+, K+, NH4+, Mg2+, Ca2+) and anions [Cl-, NO3-, SO4(2-), CH3SO3(-) (MSA)] by ion chromatography. Main sources of these ions were discussed by combined enrichment factors and correlation analyses. The concentration of total water-soluble ions ranged from 30.9 microg x m(-3) to 58.8 microg x m(-3) over the BS and from 5.03 microg x m(-3) to 39.8 microg x m(-3) over the NYS, respectively, with averages of (40.3 +/- 10.1) microg x m(-3) and (19.2 +/- 11.8) microg x m(-3). Analytical results showed that the level of the second ions (nss-SO4(2-), NO3(-) and NH4+) were the highest, accounting for 87.5% and 62.8% of total identified ions over the BS and the NYS. Enrichment factors showed that Mg2+ and Cl-mainly came from oceanic sources and the main source of K+ was crust. The analysis of sulfate source showed that sea-salt sulfates over the BS and the NYS accounted for 1.2% and 12.1% of the total sulfate and contributions of biogenic sulfates to nss-SO4(2-) were 5.0% and 14.6%, respectively, indicating that human activities were the main source of sulfate in aerosol in the study area.