机动车源大气颗粒物表面形貌及元素含量分析

应用场发射扫描电镜及X射线能量光谱仪,基于分形理论,研究不同采集区域的机动车源大气颗粒物表面形貌盒维数及其元素构成特征。结果表明,柴油机原排颗粒物大多呈球状,主要元素为C和O,粒径级较小的颗粒物粘结严重,比表面积大,形貌盒维数较大。粒径级较大的机动车扩散区域大气颗粒物呈现棱块状,Ca和Si元素含量逐渐上升,表明大粒径级颗粒物中含较多的矿物和扬尘。对于不同源的颗粒物,随着粒径级减小,其表面形貌盒维数均逐渐增大。

Analysis of Morphology and Element in Atmospheric Particulate Matters from Motor Vehicles

Morphology box dimension and element contents of atmospheric particulate matters from motor vehicles in different regions were analyzed by using the field emissions scanning electron microscope(FESEM), energy dispersive X-ray spectroscopy(EDX) and fractal theory. The results show that most of raw particulate matters from diesel engines are spherical and contain a great number of carbon and oxygen, and the particulate matters of small size are more agglomerative and therefore present greater box dimensions due to the large specific surface areas. The particulate matters of large size among those atmospheric ones collected from typical vehicle regions are prismatic and contain more calcium and silicon, which indicates there are many minerals and dust in big particulate matters. With the decrease in particulate matter size, the box dimension of each particulate matter from different sources increases.