Chemical Characteristics of Aerosol Composition over the Yellow Sea and the East China Sea in Autumn

The total suspended particulate (TSP) samples over the Yellow Sea and the East China Sea were collected to determine themajor compositions of water-soluble ionic species during two cruises in autumn 2007. The aerosol compositions exhibited an obvious regional variation between the two cruises, with higher concentrations (except Na+ and Mg2+) over the northern Yellow Sea during the first cruise. The concentrations of the secondary ions [non-sea salt sulfate (nss-SO42-), NO3-, and NH4+] were 11 +/- 4.9, 3.1 +/- 2.1, and 3.7 +/- 2.6 mu g m(-3), respectively, which together contributed over 72% of the total determined ion concentrations. Significant correlations between these secondary ions were found within each sampling period, while nss-K+ and nss-Ca2+ showed strong correlation with each other. The calculated results of equivalent concentrations of anions (nss-SO42- and NO3-) and cations (NH4+ and Ca2+) showed that the acidic species were mostly neutralized with the alkaline species over the study areas. The mass ratio of nss-SO42-/NO3- was 1.4 during the investigation period. In addition, the concentrations of MSA were 0.011 +/- 0.044 and 0.0081 +/- 0.0047 mu g m(-3) during the two cruises, respectively. Based on the measured MSA, nss-SO42-, and their ratios, the relative biogenic sulfur contribution to the total nss-SO42- was estimated to be only 2.0% during the two cruises, further suggesting the major contribution of anthropogenic source to sulfur budget over the marginal seas of China.