Micro-structural analysis of individual aerosol coarse particles during different seasons at an eastern coastal site in India

Özet

Micro-structural analysis of PM samples collected during various seasons (from July-2012 to August2013) were carried out by Field Emission Scanning electron microscopy (FESEM), Transmission Electron Microscope (TEM) coupled with Energy Dispersive X-Ray Analysis (EDX) and Selected area electrondiffraction (SAED) image for in-depth analysis of their morphology, elemental composition and crystalpattern. Significant variation was observed in the particle size and surface morphology during thedifferent seasons of a year. Four different types of particles were commonly observed among which thecarbonaceous particles, mainly the soot aggregates were found to be the most abundant species in thePM samples. Few biogenic particles were observed, mostly during post-monsoon period, with distinctmicrostructure in comparison to other particles. Micro-structural analysis also gives an indication abouttheir post-production history e.g., the age of aerosol particles, turbulence of the air, agglomeration etc.that influences aerosol microstructure. Most of the elements including transition metals were observedto be present in the form of metal oxides from their EDX pattern. Key source of the aerosol particles werefrom crustal, industrial, biological, and marine or sometimes from long range transport.