Concentration, heavy metal content, mineralogy and morphology of PM2.5 collected in central district of Tehran (case study on Hafte-Tir Square)

Gohari, Mahsa Saadat; Qishlaqi, Afshin

Volume 8, Issue 1 (Spring & Summer 2022) KJES 2022, 8(1): 118-143 | Back to browse issues page

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Gohari M S, Qishlaqi A. Concentration, heavy metal content, mineralogy and morphology of PM2.5 collected in central district of Tehran (case study on Hafte-Tir Square). KJES 2022; 8 (1) :118-143
URL: http://gnf.khu.ac.ir/article-1-2794-en.html

Concentration, heavy metal content, mineralogy and morphology of PM2.5 collected in central district of Tehran (case study on Hafte-Tir Square)

Mahsa Saadat Gohari

, Afshin Qishlaqi ^*

1- , qishlaqi@shahroodut.ac.ir

Abstract: (1155 Views)

The aim of this study is to determine the ambient concentration, content of heavy metals and morphology and mineralogy of PM_2.5samples collected from air pollution monitoring station in Haft-Tir square (central Tehran). For this purpose, PM_2.5samples were collected by means of low-volume sampling device during five months (April-August 2019). Based on the obtained results, there is more loading of PM_2.5 on June higher that 10 μgm⁻³ and showed high to very high pollution level. Variations in metal concentration in the sampling months were relatively similar, showing order of Zn>Ni>Pb>Cr>Cu>Cd. Comparing the mean concentration of metals with international permissible limits the concentration of Pb and Cr in PM_2.5samples was lower than that of recommended by the WHO while the average concentration of Cd and Ni was higher than those of USEPA recommended limit. Calculations of enrichment factor and results of principal component analysis revealed that Cr is of geogenic origin, Cd and Zn are derived from anthropic sources and Pb, Cu and Ni are probably of mixed sources. Based on scanning electron microscopy images, PM_2.5are observed as a shapeless or irregular, rod-shaped, irregular spherical, completely spherical, sheeted, as well as long chain aggregates or single crystals. According to the results of X-ray diffraction analysis, clay minerals, quartz and calcite were found as major minerals, gypsum and dolomite minerals were identified as minor minerals and wüstite and halite minerals were identified as rare mineral phases.

Keywords: PM2.5, heavy metals, mineralogy, particle morphology, Hafte-Tire, Tehran

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Type of Study: Original Research | Subject: Environmental Geology
Received: 2021/12/20 | Accepted: 2022/06/22 | Published: 2022/09/13