Abstract
In order to characterize atmospheric aerosols of desert areas in China, various aerosol samples were collected during the periods of yellow sand episode and non-episode at Alashan and adjacent in the Inner Mongolia Autonomous Region and the Ningxia Autonomous Region. Water-soluble ion concentrations in the atmospheric aerosols, ion equivalent balance, acidity and buffering ability of size-segregated atmospheric aerosols were studied. The results showed that : (1) Ca2+, Na+ and SO42- ions were the main chemical components of atmospheric aerosols in the areas, and occupied about 70% and 20% in total cation, and about 70% in total anion, respectively; (2) the buffering ability (ΔCb) of aerosols in these areas was very high up to 1,730 neq/m3 even in the period of non-eqisode; (3) aerodynamic diameter of fine particles was smaller than 1.1 μm, the equivalent balances between cation and anion were apparent, and the predominance of cation was obvious for particles larger than 2.1 μm; (4) the peak of mass concentration of aerosols was in the size range of 2.00∼ 5.00 μm during the sand storm, which is equal to the aerodynamic diameter of particles observed for long distance transportation. Strong buf3fering ability and low acidity of the atmospheric aerosols may play a significance role in the neutralization of acidic aerosols during long-rang transportation and regional acid rain.
