中国西北沙尘源区与日本沉降区大气气溶胶粒子理化特征及对比

Physiochemical Properties of Atmospheric Aerosol Particles over Sand-dust Source Areas and Sedimentary Areas in Asia

无论有无沙尘暴,低层大气气溶胶粒子浓度几乎不随高度变化。在沙尘源区,大气气溶胶粒子主要来源于地面沙尘,沙尘暴发生时气溶胶粒子的浓度大增,浓度峰值向粗粒径范围移动;在沙尘沉降区日本,当浮尘期时气溶胶粒子有地面沙尘和工业排放物两个来源,形成双峰型分布,当非浮尘期时气溶胶粒子主要是工业排放物来源,在<2.1μm细粒径范围形成一个峰值。水溶性成分也不相同,沙尘源区粒子以Ca2+、SO2-4、Na+、Cl-等沙尘来源离子为主,在3 3～4 7μm形成浓度峰值;沙尘沉降区以NH+4、NO-3等工业来源离子为主,在<2 1μm形成峰4、SO2-值。沙尘源区气溶胶粒子水不溶相都表现出K、Na元素亏损的特征,说明其气溶胶粒子是上部陆壳经过K、Na大陆化学风化的产物。

Over the sanddust source areas in northwestern China, the concentration and the granularity distribution of atmospheric aerosols don't change with height whether during duststorm or no duststorm periods. When duststorms break out sanddusts on the underlying surface are intensively blew into air and the peak value of the concentration of atmospheric aerosols shifts towards coarser particles. Over Wako of Japan, a sanddust sedimentary area, the curves of concentration distribution of atmospheric aerosol particles are bimodal during Kosa but unimodal during no Kosa. The former reflects that the atmospheric aerosol particles come from two sources: the continental deposit and the local industrial discharge, and the latter reflects that the atmospheric aerosol particles only come from the local industrial discharge. The watersoluble components of the atmospheric aerosol particles over the sanddust source areas are predominated by Ca2+, SO2-4, Na+ and Cl-, but over the sanddust sedimentary area by NH+4, SO2-4 and NO-3. The waterinsoluble components of the atmospheric aerosol particles over the sanddust source areas are deficient in K and Na, which reveals that the aerosol particles over the sanddust source areas have undergone the chemical weathering of K, Na stages, this weathering had occurred before forming the atmospheric aerosol particles.Key words: aerosol particles; sanddust sources; industrial discharge; components