上海市灰霾天大气颗粒物浓度及富集元素的粒径分布
摘要
The concentration of airborne particles (0.03–4.4 µm) in clear and haze days in Shanghai was online investigated by ELPI (electrical low pressure impactor). The concentration of typical elements (K, Ca, Ti, Mn, Cr, Ni, Cu, S, Cl, Zn, As, Pb, Fe) was measured by synchrotron radiation X-ray fluorescence. In this work, Fe was used as the reference element to demonstrate the enrichment of other elements. Experimental results show that, the concentration of airborne particles appeared bi-modal in haze days while appeared single modal in clear days. Also, the particle number concentration showed more remarkable peaks in size segregated particles (0.07–0.3 µm) in haze days than in clear days. Ca, Ti, Cl, Mn, Cr, Zn, As, Pb exhibited single modal in clear days and exhibited bi-modal in haze days; K exhibited single modal in clear and haze days; Cu, S exhibited bimodal in clear and haze days; Ni exhibited bi-modal in clear days and exhibited tri-modal in haze days; Cu, S, Ni showed prominent differences in clear and haze days. For the reason that the enrichment factors of K, Ca, Ti, Mn, Cr were less than 10, they were mainly from natural sources. The enrichment factors of Cl, Pb, As, Ni, Cu, S, Zn were much larger than 10 in clear and haze days, and also the enrichment factors of Ni, Cu, S, Zn were obviously larger in haze days than in clear days.