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Dust sampling equipment exhibits significant variations over time depending on the operating principle, being influenced by interaction of environmental factors, such as air flow velocity, relative humidity, ambient temperature and barometric pressure. The objective of this study is to perform a comprehensive comparative evaluation between the gravimetric reference method and the optical method for determining PM10 particles in ambient air. In order to allow the evaluation of each observation in relation to method...

This study investigates experimentally the influence of dust thermal conductivity on the maximum surface temperature of Ex equipment operating under dust layer conditions at a fixed dissipated power of 3 W. Experiments were conducted using a purpose-built resistive test sample, designed and manufactured at INCD INSEMEX, tested with two dust materials representing boundary conditions of thermal behaviour: vermiculite, selected as a worst-case insulating material, and Portland cement dust, selected for its industria...

The present study aims to track the influence of location and climate dynamics on the distribution and relationship of fine particulate matter (FPM) and airborne microorganisms. Hot spots, green urban areas and green peripheral areas in five Bulgarian cities with different climatic specificities were studied - Sofia, Plovdiv, Stara Zagora and Burga. The samples were collected using an air spinner. The total number of microorganisms was established, as well as the percentage of individual microbiological groups rel...

In terms of its influence on human health, noise has a significant effect. One type of noise is generated by tire/road contact while a vehicle is in motion. This noise is monitored and analyzed using the CPX (Close-ProXimity) method according to ISO 11819-2, in which microphones are used to measure the noise generated by a rolling reference tire. The level of this type of noise is determined by various factors. One of these factors is the macrotexture of the road surface, that is, the texture of the road surface a...

This study investigates the transport dynamics of heavy metals and metal-containing nanoparticles from mining-affected areas through major Georgian river systems into the Black Sea, with a focus on environmental risk assessment. Mining activities in Georgia represent a significant source of metal contamination, influencing both dissolved and particulate phases within riverine environments. A spatial monitoring approach was applied along upstream–downstream gradients to evaluate the distribution of metals in wate...

This study presents a numerical analysis of resonator configurations for acoustic agglomeration in air purification applications. The efficiency of acoustic agglomeration is determined by the spatial distribution of acoustic pressure, which is controllably modified through mechanically deformable resonators. The investigation employs finite element analysis in a sequential multiphysics approach (ANSYS Workbench), comprising modal analysis for natural frequencies and mode shapes, harmonic acoustic analysis for defo...

Mercury is among the most hazardous trace elements released during fuel combustion, yet its occurrence in biomass and biomass ash remains insufficiently constrained. This paper presents an integrated assessment of published data on Hg contents, associations, and probable modes of occurrence in eight biomass types and their ashes generated during combustion, with emphasis on Hg volatilization, retention in biomass ash, and comparison with industrial coals used in Bulgaria. Published chemical, mineralogical, thermal...

Fine particles with a diameter of 2.5 microns or less (PM2.5) lead to dangerous air pollution, which can penetrate deep into the lungs and cause health damage by causing respiratory and cardiovascular diseases. PM2.5 appears mainly as a result of combustion processes such as car operations, burning coal, wood, fuel oil in CHP and in the private sector, as well as through industrial emissions and fires. High-efficiency particulate air (HEPA) filters effective used for capturing these harmful particles, but we have ...

The present study aims to track the seasonal dynamics of airborne microorganisms on the territory of Sofia, Bulgaria in relation to the dynamics of fine particulate matter (FPM). Seven sampling points were selected from which sampling was carried out in seasonal dynamics. A laboratory Spin Air sampler was used as 1 m3 of air was passed through the apparatus. For the purpose of the study, the total number of microorganisms was established, as well as the quantity of the main microbiological groups. Isolation of pur...

The coal mining waste dump of Petrila in the Jiu Valley, Romania, represents a significant source of environmental hazards due to spontaneous combustion of coal residues. This study investigates the generation of nitrogen oxides (NO, NO2, and NOX), carbon dioxide (CO2), and methane (CH4) from the Petrila dump, focusing on their correlation with self-heating phenomena and internal temperature variations. Field observations were conducted on the dump, recording signs of surface smoke, elevated temperatures, and othe...