Morphology and mineralogy of ambient particulate matter over mid-Brahmaputra Valley: application of SEM–EDX, XRD, and FTIR techniques

Abstract Ambient particulate matter (PM), collected during a dust event over mid-Brahmaputra Valley of India, was characterized. The PM samples were analyzed using scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDX), diffraction (XRD), and Fourier transform infrared (FTIR) techniques. SEM micrographs revealed varied shapes the PM, viz. spherical, irregular, angular, cluster, flaky, rod-like, crystalline agglomerate structures indicating probable nature their sources formation as biogenic, geogenic, or anthropogenic. Some biogenic particles like plant materials, pollens, diatoms captured under SEM. presence diatom in indicative wind-blown from dried bed Brahmaputra River. honeycomb-like brochosomes secreted by leafhoppers Cicadellidae family also captured. On contrary, background sample had mostly carbonaceous particles. XRD FTIR analyses indicated quartz, feldspar, kaolinite, illite, augite, calcium aluminum silicate, cerussite, calcite, montmorllonite, organic carbon. airmass backward trajectory analysis explained local contribution dust.