Sequential SEM-EDS, PLM, and MRS Microanalysis of Individual Atmospheric Particles: A Useful Tool for Assigning Emission Sources

Microscopic characteristics and sources of atmospheric dustfall in open-pit mining coal resource-based city in the arid desert area of Northwest China

Atmospheric dustfall is solid air pollutant, has a major impact on the environment and human health. The objective of this study was to investigate the microscopic characteristics and sources of atmospheric dustfall in open-pit mining coal resource-based city in the arid desert area of Northwest China. The characteristics of size and shape factors, variation of shape factors with size distribution, types of individual particles, and sources of atmospheric dustfall, which were collected in the open-pit mining area and surrounding areas, were analyzed by X-ray diffraction (XRD) and scanning electron microscopy coupled with an energy dispersive spectrometer (SEM-EDS) combined with graphical method and shape factors. The results showed that the atmospheric dustfall in all functional areas was dominated by coarse-grained particles. The shape of the atmospheric dustfall deviated from spherical shape, and with decreasing particle size, the difference in shape factors increased in each functional area. The EDS and XRD analyses indicated the presence of 13 types of particles. The sources were mainly local and included soil dust from each functional area; industrial dust, construction dust, biogenic impurities, fossil fuel combustion, wear products of motor vehicle parts, motor vehicle exhaust emissions, and emission and excreta from biological activities in each functional area except the desert area; emissions from a steel plant in the industrial area; coal-associated ore, coal dust, coal gangue emissions, and emissions from the spontaneous combustion of coal gangue in the open-pit mining area; secondary chemical crystallization products in the industrial area and the open-pit mining area; dust generated by vehicles abrading the surface of the off-mine coal road and in the open-pit mining area.

Elemental Composition of PM2.5 and PM10 and Health Risks Assessment in the Industrial Districts of Chelyabinsk, South Ural Region, Russia

Air pollution impacts all populations globally, indiscriminately and has site-specific variation and characteristics. Airborne particulate matter (PM) levels were monitored in a typical industrial Russian city, Chelyabinsk in three destinations, one characterized by high traffic volumes and two by industrial zone emissions. The mass concentration and trace metal content of PM2.5 and PM10 were obtained from samples collected during four distinct seasons of 2020. The mean 24-h PM10 ranged between 6 and 64 μg/m3. 24-h PM2.5 levels were reported from 5 to 56 μg/m3. About half of the 24-h PM10 and most of the PM2.5 values in Chelyabinsk were higher than the WHO recommendations. The mean PM2.5/PM10 ratio was measured at 0.85, indicative of anthropogenic input. To evaluate the Al, Fe, As, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn concentration in PM2.5 and PM10, inductively coupled plasma mass spectrometry (ICP-MS) was used. Fe (337-732 ng/m3) was the most abundant component in PM2.5 and PM10 samples while Zn (77-206 ng/m3), Mn (10-96 ng/m3), and Pb (11-41 ng/m3) had the highest concentrations among trace elements. Total non-carcinogenic risks for children were found higher than 1, indicating possible health hazards. This study also presents that the carcinogenic risk for As, Cr, Co, Cd, Ni, and Pb were observed higher than the acceptable limit (1 × 10-6).

Geochemical-Microscopical Characterization of the Deterioration of Stone Surfaces in the Cloister of Santa Maria in Vado (Ferrara, Italy)

Santa Maria in Vado is a monument in the rich artistic heritage of the city of Ferrara (north of Italy). In this paper we want to investigate the state of conservation of tombstones, cloister and the entrance to the basilica, in order to keep them in the best possible state for the future generations. From the chemical characterization, the state of conservation was determined focusing on the biodeteriogenic and non-biodeteriogenic factors, which determine a series of unwanted changes in the physical, mechanical and above all aesthetic properties of the material, often closely connected with the environment and conservation conditions. On the macroscopic observation, the state of conservation of the tombstones appeared to be very deteriorated through aesthetic and structural damage. In detail, the stereo microscope observation of samples collected from the tombstones show the presence of efflorescence probably caused by the abundant of water that bring the salts present inside the rock into solution. Relating the columns, μ-XRF analysis confirm the carbonate composition of samples and presence of iron and sulfur. Finally, SEM observation highlighted the presence of black crust on arch samples and the presence of pollen on the black crust and spheroidal particles probably related to atmospheric pollution.