The field emission scanning electron microscopy coupled with energy dispersive X-ray spectrometry (FESEM-EDX) was employed for morphological characterization and elemental microanalysis of individual particles. Size distribution of analyzed particles were found between 0.2 and 1.0 μm which displayed a bimodal distribution in the q-Acc range (0.25–0.50 μm and 0.50–1.0 μm). Soot particles, Tar balls (TBs) and dust particles were classified on the basis of SEM images and elemental composition. Shape descriptor parameters such as circularity (Circularity: 0.62–0.72) and aspect ratio (AR: 1.50–1.88), inferring that particles were not perfectly spherical and not elongated in any uniform direction. Besides, the values of sphericity varied from 0.10 to 2.88 (mean: 1.22) thereby suggesting deviation of the shape (from spherical to non-spherical) in micro-environments. Decreasing trend of roundness and increasing trend of AR with increasing D_Aeq (Area equivalent diameter) suggest that particles with higher D_Aeq are more elongated in nature. The value of roundness (RN) varies from 0.18 to 0.98 (mean 0.68) suggesting particle shape varies from nearly perfectly spherical to irregular shape. Furthermore, particles were found to be more spherical in HIG than MIG and LIG which points towards more soot and TBs. The elements such as Si, Mg, Ca and fewer amounts of Al, Fe and K were observed in PM_1.0-0.5. While Fe, K, Mg were found in PM_0.50-0.25 μm size having crustal origin.

场发射扫描电子显微镜与能量色散X射线光谱法（FESEM-EDX）结合用于单个颗粒的形态表征和元素微观分析。发现分析颗粒的尺寸分布在0.2至1.0μm之间，在q-Acc范围（0.25–0.50μm和0.50–1.0μm）中显示出双峰分布。根据SEM图像和元素组成对烟尘颗粒，焦油球（TBs）和灰尘颗粒进行了分类。形状描述符参数，例如圆度（圆度：0.62-0.72）和长宽比（AR：1.50-1.88），可以推断出粒子不是完美的球形，并且在任何均匀方向上都不会伸长。此外，球形度的值从0.10到2.88不等（均值：1。22）从而暗示了微环境中形状的变化（从球形到非球形）。圆度减小趋势，AR随增大趋势增大D _Aeq（面积当量直径）表明，具有更高D _Aeq的粒子在本质上会更长一些。圆度（RN）的值在0.18到0.98（平均0.68）之间变化，表明颗粒形状从几乎完美的球形到不规则形状变化。此外，发现HIG中的颗粒比MIG和LIG的球形更强，这表明更多的烟灰和TB。在PM中观察到，例如Si，Mg，Ca和量较少的Al，Fe和K的元素_1.0-0.5。发现Fe，K，Mg的PM尺寸为_{0.50-0.25μm，}具有地壳起源。