In-Depth Analysis of Physicochemical Properties of Particulate Matter (PM10, PM2.5 and PM1) and Its Characterization through FTIR, XRD and SEM–EDX Techniques in the Foothills of the Hindu Kush Region of Northern Pakistan

Abstract

The current study investigates the variation and physicochemical properties of ambient particulate matter (PM) in the very important location which lies in the foothills of the Hindu Kush ranges in northern Pakistan. This work investigates the mass concentration, mineral content, elemental composition and morphology of PM in three size fractions, i.e., PM1, PM2.5 and PM10, during the year of 2019. The collected samples were characterized by microscopic and spectroscopic techniques like Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) spectroscopy. During the study period, the average temperature, relative humidity, rainfall and wind speed were found to be 17.9 °C, 65.83%, 73.75 mm and 0.23 m/s, respectively. The results showed that the 24 h average mass concentration of PM10, PM2.5 and PM1 were 64 µgm−3, 43.9 µgm−3 and 22.4 µgm−3, respectively. The 24 h concentration of both PM10 and PM2.5 were 1.42 and 2.92 times greater, respectively, than the WHO limits. This study confirms the presence of minerals such as wollastonite, ammonium sulphate, wustite, illite, kaolinite, augite, crocidolite, calcite, calcium aluminosilicate, hematite, copper sulphate, dolomite, quartz, vaterite, calcium iron oxide, muscovite, gypsum and vermiculite. On the basis of FESEM-EDX analysis, 14 elements (O, C, Al, Si, Mg, Na, K, Ca, Fe, N, Mo, B, S and Cl) and six groups of PM (carbonaceous (45%), sulfate (13%), bioaerosols (8%), aluminosilicates (19%), quartz (10%) and nitrate (3%)) were identified.

Morphological, Mineralogical, and Biochemical Characteristics of Particulate Matter in Three Size Fractions (PM10, PM2.5, and PM1) in the Urban Environment

“…Minerals found with the help of FT-IR are not necessarily traceable in XRD due to differences in the crystalline structure. Minerals found at different 2θ are chrysotile 18 and FeSO 4 (44°), which were detected by Usman et al 18 Most of the minerals detected in XRD are in good agreement with FT-IR analysis. To further determine the crystallinity of the sample, we have calculated the crystallinity index of our samples by dividing the area of all crystalline peaks by the sum of all crystalline and amorphous peaks.…”

“…In all samples, particles with spherical shapes are anthropogenic, induced by humans. 5,18 Complete size distribution histograms of 70 particles in the samples were from the SEM images using Nano Measurer 1.2 software 6,35 and displayed in Figure 9a−c. The sample PM 1 shows a size distribution range from 0.2 to 1.6 μm, with an average particle size of 0.75 μm, as shown in Figure 9a.…”

“…The average particle size of PM 1 , PM 2.5 , and PM 10 agreed with the previous reports. 6,18,35 The larger size, up to 18 μm, may have occurred due to the particle accumulation on the filter.…”

Breathing Fresh Air in the City: Implementing Avenue Trees as a Sustainable Solution to Reduce Particulate Pollution in Urban Agglomerations

“…), and others, which are detected by inductively coupled plasma with atomic emission spectroscopy (ICP-AES) [ 87 ] and inductively coupled plasma optical emission spectroscopy (ICP-OES) [ 88 ]. On the other hand, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) are used to identify minerals [ 89 ]. Field emission electron microscopy (FE-SEM) combined with energy-dispersive X-ray (EDX) are also used to analyze these elemental compositions and morphologies [ 89 ].…”

“…On the other hand, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) are used to identify minerals [ 89 ]. Field emission electron microscopy (FE-SEM) combined with energy-dispersive X-ray (EDX) are also used to analyze these elemental compositions and morphologies [ 89 ].…”