No abstract

The first results of the research of the distribution of welding aerosol nano- and microparticles in the working area based on substance and morphological analysis are presented in the paper. A 3D-model of the welding aerosol cloud demonstrating the distribution of nano- and microparticles in the working area of the welder was created using the granulometric data of the samples. The most dangerous area with maximum density of nano- and microparticles of welding fumes was singled out: 1.3 m in height and 5 meters in all directions.Welding aerosol is a disperse system in which the solid component of the welding aerosol (SCWA) acts as the phase, and the mixture of gases (gaseous component of welding aerosol, or GCWA) – as the medium. SCWA stays suspended in the air for a long time spreading far beyond the working area of a welder [1].The aim of this work was to create a 3D-model of a welding aerosol cloud, demonstrating the spread of nano- and microparticles of welding aerosol in the working area of a welder. The 3D model was created using granulometric data of samples collected by the author’s method.

The production of cement is associated with the emissions of dust and particulate matter, nitrogen oxides (NO x ), sulfur dioxide (SO 2 ), carbon monoxide (CO), heavy metals, and volatile organic compounds into the environment. People living near cement production facilities are potentially exposed to these pollutants, including carcinogens, although at lower doses than the factory workers. In this study we focused on the distribution of fine particulate matter, the composition, size patterns, and spatial distribution of the emissions from Spassk cement plant in Primorsky Krai, Russian Federation. The particulate matter was studied in wash-out from vegetation (conifer needles) using a hybrid method of laser diffraction analysis and Raman spectroscopy. The results showed that fine particulate matter (PM 10 fraction) extended to the entire town and its neighbourhood. The percentage of PM 10 in different areas of the town and over the course of two seasons ranged from 34.8% to 65% relative to other size fractions of particulate matter. It was further shown that up to 80% of the atmospheric PM content at some sampling points was composed of cement-containing particles. This links the cement production in Spassk-Dalny with overall morbidity of the town population and pollution of the environment.

Arc welding operations are considered to be risky procedures by generating hazardous welding fume for human health. This study focuses on the key characteristics, as well as dispersion models, of welding fumes within a work zone. Commercial and widely used types of electrodes with various types of covering (rutile, basic, acidic and rutile-cellulose) were used in a series of experiments on arc welding operations, under 100 and 150 amps of electric current. According to the results of this study, maximum levels of pollution with particles of PM10 fraction occur in the workspace during arc welding operations. Disregarding the types of electrodes used, the 3D models of dispersion of the РМ10 particles at the floor plane exhibit corrugated morphologies while also demonstrate high concentrations of the РМ10 particles at distances 0–3 m and 4–5 m from the emission source. The morphology of these particles is represented by solid and hollow spheres, ‘nucleus-shell’ structures, perforated spheres, sharp-edged plates, agglomerates of the tree-like (coral) shape. At last the bifractional mechanism of fume particle formation for this type of electrodes is also shown and described. In this article results are reported, which demonstrate the hazards of the arc welding process for human health. The results of the characterization of WFs reported improve our understanding of risks that these operations pose to human health and may strengthen the need for their control and mitigation.

Presented method of kinetic analysis of non-isothermal reaction data provides precise kinetic parameters for different materials with different morphology and particle size.