厦门城区秋季不同粒径大气颗粒物的微观形貌分析

Abstract

应用场发射扫描电镜(fESEM)研究了厦门城区秋季(2013年11月)不同粒径大气颗粒物的微观形貌及其元素组成特征.结果表明,厦门城区的大气颗粒物主要有烟尘集合体、飞灰颗粒、矿物颗粒、生物颗粒等.在粗粒径范围(>2.5μM),不规则矿物颗粒占多数,主要来自路面或建筑扬尘;细粒径颗粒物(<1.0μM)主要为大气二次反应产生的含硫、含氮颗粒,以及燃烧排放的烟尘集合体.飞灰颗粒和烟尘集合体在不同的粗、细粒径段都有存在.2013年秋季厦门城区大气污染以化石燃料燃烧、机动车尾气、扬尘为主,是今后大气环境防治中的主要控制对象.

Morphology and element composition of atmospheric aerosols with different sizes in Xiamen collected in autumn(November,2013)were investigated with field emission scanning electron microscopy(FESEM).Four main types of particles were identified including soot aggregates,fly ashes,minerals and biological particles.The irregular mineral particles were prevailing in the particles of coarse sizes(>2.5μm),mainly originating from road dust and construction dust.The composition of fine particles(<1.0μm)were mainly sulphates and nitrates.Soot aggregates and fly ashes almost appeared in every scope of sizes of aerosols,indicating that fine particles discharged from combustion evolved from small sizes to big ones because of agglomeration.All these features indicated that the particles mainly originated from fossil fuel burning,motor vehicle particles,dusts over the Xiamen City in autumn 2013,and much attention should be paid to control air pollution.