Aircraft measurements of aerosol ionic species over eastern coastal,Yangtze River areas and Pearl River delta of China

摘要

Aircraft measurements were carried out over eastern coastal areas in spring and winter, Yangtze River areas in summer and spring and Pearl River delta region in autumn of china, respectively. Eight ionic components of particulate matters were sampled by filters. In these experiments, nitrate, sulfate and ammonium were the main water-soluble components in particulate matters. The total fraction of SO42- and NH4+ accounted for over 60% in PM10 and PM2.5. Crustal species (K+, Ca2+ and Mg2+} had lower fractions (less than 5%). These indicate that coal combustion pollution is the main pollution type in most regions of China. For latitudinal distribution, the concentrations of ionic species observed in northern regions were higher than those obtained in southern regions. It is due to the effects of coal burning for wanning in winter and dust storm in spring in northern areas. For longitudinal distribution, the concentrations in south-western region were obviously lower than those in eastern region. Vertical distribution of ionic species showed a general decreasing trend with increasing flight altitude. For seasonal variation, the ionic species has lower concentration in summer due to wet deposit. Analysis of correlations between ionic species suggests that these components had the same source, i.e., they are mainly influenced by anthropogenic source. NH4+ and SO42-were strongly correlated, indicating that combustion was the dominant source, and they existed as (NH4)SO4 and NH4HSO4. The depletion of Cl- was existed in air-suspended particles. The ratio of SO42- to NO3- is between 1.0 and 4.0, indicating paniculate matters mainly come from emission of coal burning in China.