【摘要】 本文应用高分辨率场发射扫描电镜(FESEM)获得北京西北城区2002年春季可吸入颗粒物显微形貌图片,并利用数字图像粒度分析系统得到可吸入颗粒物中烟尘集合体、燃煤飞灰、矿物等三种主要颗粒的数量-粒度分布数据。结果表明,北京市西北城区2002年春季可吸入颗粒物的粒径主要分布在1～2 5μm之间,其次在2 5～10μm之间,矿物颗粒占总颗粒数量的82 25%。对矿物颗粒的数量-粒度分布和体积-粒度分布进行对比表明,小于5μm的颗粒虽然在体积上只占20%,但在数量上却达90%。因为颗粒越细,其比表面积越大,吸附的有害物质也越多,所以细颗粒物今后应深入研究。更多还原

【Abstract】 The microscopic images of airborne inhalable particles, collected in the air of a northwestern urban site in Beijing during spring 2002, were obtained by high resolution field emission scanning electron microscopy (FESEM). Three major types of particles were recognized, including soot aggregates, coal fly ashes and mineral particles. The size data of these three types of particles were obtained by the image analysis system. Their number-size distribution showed that the particles were mainly concentrated in the range of 1μm to 2.5μm, followed by the range of 2.5μm to 10μm, and the mineral particles took up 82.25% by number. A comparison between number-size and volume-size distributions of mineral particles demonstrated that mineral particles smaller than 5μm, though occupied 20% by volume, accounted for up to 90% by number. It was suggested that finer particles, due to their higher surface area and higher absorption to hazardous components, should be investigated in the future.更多还原