Mineralogical Characteristics and Sources of Coarse Mode Particulate Matter in Central Himalayas

Abstract

This study investigates the morphological and mineralogical characteristics of coarse mode particulate matter (PM₁₀) over the Central Himalayan region of India (Nainital: 29.39°N, 79.45°E, 1958 m above mean sea level). X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM–EDX) techniques were employed for morphological and mineralogical analysis of PM₁₀ collected from January to December 2019. XRD and FTIR techniques identify crystalline phases, revealing minerals such as illite, kaolinite, montmorillonite, quartz, dolomite, calcite, magnetite, hematite, gypsum, halite, mascagnite, augite, albite, wollastonite, and calcium aluminium silicate hydrate (C-A-S=-H) in PM₁₀ samples. SEM–EDX analysis confirms the presence of major elements i.e., Si, Al, Ca, K, Fe, Mg, S, Na, Ba, Ti, Zn, and Cl in PM₁₀, indicating the diverse mineral formations. Elemental composition variations are observed, with Si, and Al being predominant. The minerals' elemental composition suggests geogenic sources (e.g., dust storms, rock weathering) for quartz, dolomite, albite, augite, etc., containing Al, Si, Na, Ca, Mg, and Fe. Meanwhile, illite, montmorillonite, mascagnite, hematite, calcium aluminium silicate, etc., with elements like Ca, Al, Si, Fe, K, Zn, Ti, Ba, S, and Cl, are linked to anthropogenic sources (e.g., demolition, construction, combustion, industrial and vehicular emissions). These findings contribute to a better understanding of air quality, environmental conditions, and potential health implications in the Central Himalayan region.