Characterization of individual fly ash particles in surface snow at Urumqi Glacier No. 1, Eastern Tianshan

Abstract

This research aimed to identify and characterize individual spherical fly ash particles extracted from surface snow at Urumqi Glacier No.1 (UG1), Eastern Tien Shan, central Asia. Characterization of the spherical particles (i.e. morphology, chemical composition and genesis) was obtained by scanning electron microscopy coupled with energy dispersive X-ray spectrometer (SEM-EDX). This method enabled the characterization of submicroscopic spherical particles, which were present in very small quantities. Spherical particles and agglomerates were identified according to their morphology in five snow samples. Prevalent particle types in all samples were granular spherical particles, hollow spherical particles, irregularly shaped carbonaceous particles and agglomerates. The vast majority of spherical particles in our samples had mostly smooth and glossy surfaces, although these particles varied in diameter and elemental composition. The diameter of fly ash particles ranged from 0.76 to 16.7 m, with an average of 3.79 m (median: 3.21 m). Individual particle analyses of elemental composition showed that particles formed in combustion were mainly composed of carbon, silicon, aluminum and trace elements (e.g. Na, K, Ca, Fe). Some spherical fly ash particles contained toxic heavy metals (e.g. Pb, Cr, As, Zn), and indicated that fly ash particles acted as the main possible carriers of toxic heavy metals deposited in snow and ice of glaciers in high altitudes of central Asia. On the basis of chemical information obtained from EDX, the fly ash particles deposited in the snow could be classified into four types. Namely, Si-dominant particles, with average diameters of 3.24 m were formed by industrial coal combustion via high temperature processes in typical coal-fired heating stations and thermal power plants. Moreover, Fe-dominant particles, with average diameters of 3.82 m, and Ti-dominant spherical particles formed by lower temperature processes in foundry and iron or steel plants. In addition, C-dominant particles, with average diameters of 8.43 m, formed from unburned coal. Fe-dominant particles had larger average diameters than Sidominant particles, indicating that the former were easier to form and developed earlier in the furnace because of their differential melting points of compositional oxide. Backward air mass trajectory analysis suggests that the developed urban regions of central Asia contributed the primary fly ash particles from industrial combustion to the study site through the high-level westerlies jet steam.fly-ash particles, individual particle characterization, SEM-EDX, chemical classification, Urumqi Glacier No.1

Anthropogenic- and natural sources of dust in peatland during the Anthropocene

“…This is linked with the appearance of other chronomarkers, e.g., spheroidal carbonaceous particles (SCP), whose numbers have rapidly increased everywhere after the second world war19. SAP are a typical inorganic, glassy component of fly ash generated during industrial coal combustion2122232425 and are found even in regions located far from industrial centres, e.g., Greenland (Summit area)26 and the glaciers of Tianshan27. Ranging in size from <1 up to tens of micrometers, the majority are ideal spheres, monolithic, and dense, porous or hollow.…”

Primary succession of soil enzyme activity and heterotrophic microbial communities along the chronosequence of Tianshan Mountains No. 1 Glacier, China

“…For example, SOC content in glacier foreland soils from Alaska ranged from 0.5 to 1.8 g kg -1 (from 0 to 4 years), and SOC content varied from 0.9 to 3.6 g kg -1 in Ö denwinkel and Rotmoos glacier soils (from 0 to 50 years) (Tscherko et al 2003). This was likely due to the long-term anthropogenic activities, such as industrial and agricultural production and domestic livestock production, and regional properties, such as dust transportation, geographical location, topography and local climate conditions (Zhang et al 2011;You and Dong 2011;Li et al 2011;Wang et al 2012). Glacier No.…”

“…1a). As this glacier is characterized as a combination of high mountain and desert basin and thus is frontogenetic, dust particles, or individual fly ash particles, and domestic waste from the north (Urumqi) and west (Almaty, Bishkek and Tashkent) are blocked and precipitated with rain and snow (Li et al 2000Wang et al 2012;You and Dong 2011;Zhang et al 2011). For example, Li et al (2000) found that during the past 40 years the mean organic acid content (methanoic acid, acetate, oxalate and pyruvate) in ice c Utilization efficiency of amino acids at different successional times.…”

“…Wang et al (2012) studied the carbonaceous aerosol concentration of snow and ice from the glacier and found that the concentration of total carbon was as high as 1,943 ng g -1 soil. Additionally, Zhang et al (2011) reported that more than 90 % of fly ash particles from the four Asian industrial cities near the glacier contained C (mainly from metallurgical industries and coal-fired power plants).…”

Supplementary material to &quot;Coal fly ash: Linking immersion freezing behavior and physico-chemical particle properties&quot;

“…S5 shows the ESEM images of dry-and wet-generated quasi-monodisperse CFA particles. Spherical particles, often described as the main particle type in CFA in literature (e.g., Davison et al, 1974;Ramsden and Shibaoka, 1982;Flanders, 1999;Zhang et al, 2011), were rarely detected in the dry-generated samples. Spherical shapes are thought to originate from combustion of organic substances and melting of mineral inclusions in the coal, leading to the formation of spherical ash droplets (Damle et al, 1982;Flagan and Seinfeld, 1988).…”