Chemical characteristics of aerosols at coastal station in Hong Kong. I. Seasonal variation of major ions, halogens and mineral dusts between 1995 and 1996

Aerosols samples (total suspended particulate “TSP” and PM10 particulate) were collected at coastal monitoring station in Hong Kong between 1995 and 1996. They were analyzed to investigate the seasonal cycle among major ions (Na+, NH4+–N, K+, Mg2+, Ca2+, Cl−, NO3−, and SO42−), halogen elements (Br, I) and mineral dusts. The concentration of major ions showed a summer minimum and a winter maximum in a coastal region of Hong Kong. Halogen (Br, I) and dust concentrations exhibited a very similar variation. From the molar equivalence of Na+ and Cl−, it was found that the Cl− in TSP or PM10 was deviated from sea-salt (NaCl) component. Bromine (Br) in aerosols evidently originated from marine source but iodine (I) in aerosols may have been generated from natural and anthropogenic sources including possible biomass emission. The ratios of nonsea-salt sulfate (nss-SO42−) to nitrate (NO3−) and trace elements (As, Sb, Se, Pb, V and Zn) were used to explain the different pollution emissions.