Mineralogical Characterization of PM₁₀ over the Central Himalayan Region.

The air quality of Himalayan region of India is deteriorating due to the increasing load of particulate matter that is emitted from various local and regional sources as well as transit of dust-related pollutants from the Indo-Gangetic Plain (IGP) and surrounding areas. In this study, the mineralogical characteristics of coarse mode particulate matter (PM₁₀) has been analyzed using X-Ray Diffraction (XRD) technique from January–December, 2019 over Nainital (29.39°N, 79.45°E; altitude: 1958 m above mean sea level), a central Himalayan region. XRD analysis of PM₁₀ samples showed the presence of clay minerals, crystalline silicate minerals, carbonate minerals, and asbestiform minerals. It is shown that the quartz minerals with significant levels of crystallinity were present in all the samples. Other minerals that are contributing to the soil dust are also observed in the analysis (CaFe₂O₄, CaCO₃, CaMg(CO₃)₂, calcium ammonium silicate (CAS), gypsum, feldspar, kaolinite, illite, augite, montmorillonite, and vaterite). The minerals, ammonium sulphate, hematite, koktaite, and magnetite were also found in the samples and are suggested to be from the biogenic and anthropogenic activities including biomass burning, fuel combustion, vehicle exhaust, etc. This study indicated that the majority of the minerals in PM₁₀ that were present in this Himalayan region are from soil/crustal dust.