Morphological, Mineralogical, and Biochemical Characteristics of Particulate Matter in Three Size Fractions (PM₁₀, PM_2.5, and PM₁) in the Urban Environment

Abstract

Air pollution in megacities is increasing due to the dense population index, increasing vehicles, industries, and burning activities that negatively impact human health and climate. There is limited study of air pollution in many megacities of the world including Pakistan. Lahore is a megacity in Pakistan in which the continuous investigation of particulate matter is very important. Therefore, this study investigates particulate matter in three size fractions (PM1, PM2.5, and PM10) in Lahore, a polluted city in south Asia. The particulate matter was collected daily during the winter season of 2019. The average values of PM1, PM2.5, and PM10 were found to be 102.00 ± 64.03, 188.31 ± 49.21, and 279.73 ± 75.04 μg m–3, respectively. Various characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) were used. FT-IR and XRD techniques identified the minerals and compounds like quartz, peroxides, calcites and vaterite, feldspar group, kaolinite clay minerals, chrysotile, vaterite, illite, hematite, dolomite, calcite, magnesium phosphate, ammonium sulfate, calcium iron oxide, gypsum, vermiculite, CuSO4, and FeSO4. Morphology and elemental composition indicated quartz, iron, biological particles, carbonate, and carbonaceous particles. In addition, various elements like C, O, B, Mg, Si, Ca, Cl, Al, Na, K, Zn, and S were identified. Based on the elemental composition and morphology, different particles along with their percentage were found like carbonaceous- (38%), biogenic- (14%), boron-rich particle- (14%), feldspar- (10%), quartz- (9%), calcium-rich particle- (5%), chlorine-rich particle- (5%), and iron-rich particle (5%)-based. The main sources of the particulate matter included vehicular exertion, biomass consumption, resuspended dust, biological emissions, activities from construction sites, and industrial emissions near the sampling area.

Wintertime investigation of PM10 concentrations, sources, and relationship with different meteorological parameters

“…However, the production of NH 4 + is more influenced by traffic and coal combustion. Agricultural/animal husbandry, fertilizer, wastewater treatment, ammonium bisulfate, or nitrate, are the sources of the cations, namely ammonium (NH 4 + ) 67 . Marine/sea salt, dry lakes, and de-icing materials all produce sodium (Na + ).…”

Application of a Multi-Technique Approach to the Identification of Mineral Polymorphs in Histological Samples: A Case of Combined Use of SEM/EDS and Micro-Raman Spectroscopy

“…In the first kind of particles reported in this paper (Figure 1), the chemical characterization detected the presence of calcium, but it was impossible to understand if it was a calcium carbonate, because of the presence of the carbon of the polycarbonate filter. So, it might be classified only as a general "calcium rich particle" [31]. The successive analysis carried out applying micro-Raman spectroscopy allowed to better classify these particles and bundles of fibers also under the mineralogical characteristics, ascribing them to aragonite [25,26], a calcium carbonate polymorph-together with calcite and vaterite-chemical formula CaCO 3 [9].…”