Search Results (143)

The occupational health implications of solar photovoltaic (PV) recycling remain critically under-investigated. This study assessed occupational exposure across the PV recycling value chain in Taiwan, evaluating primary mechanical dismantling and downstream reuse sectors (glass milling and controlled low-strength material [CLSM] batching). Area and personal samples were analyzed for total dust, respirable dust, and trace heavy metals. Results indicated that primary mechanical crushing yielded relatively low ambient dust and negligible toxic heavy metal (e.g., Pb, Cd) aerosols, attributed to the macroscopic ductility of metallic ribbons and EVA shock-absorbing properties. Conversely, a critical “hazard transfer” phenomenon was empirically identified downstream, where intensive secondary grinding and aggregate blending in the downstream reuse sector (glass milling and CLSM batching) systematically shifted the aerodynamic particle size distribution, causing the respirable dust fraction to surge to 38.9–72.6%. The pursuit of zero-waste material circularity inadvertently amplifies highly dispersive, respirable dust hazards in downstream sectors, necessitating targeted occupational exposure controls. Full article

Efficient capture of respirable dust remains difficult in fully mechanized excavation roadways because fine particles readily migrate with airflow beyond the effective spray region. Here, a wind-assisted negative-pressure dust suppression device was developed by integrating annular Venturi entrainment with a mechanical air duct, enabling coupled airflow induction and droplet transport. The device was optimized using nozzle atomization tests, CFD-based orthogonal simulations, and laboratory-scale validation. The results show that an SK508 solid-cone nozzle provides suitable atomization for Venturi-induced suction. Using induced air inlet velocity and diffuser-inlet static pressure as evaluation indicators, the optimal Venturi unit was obtained at 0.1 MPa water pressure, 0.4 MPa air pressure, a 15° diffuser angle, and a throat-center nozzle position. For the integrated device, the best configuration was ten Venturi tubes, an impeller rotational speed of 2400 r/min, and an impeller position of 300 mm from the air duct inlet. In laboratory-scale tests, the complete wind-assisted negative-pressure mode outperformed fan-only, spray-only, wind-assisted spray, and negative-pressure secondary dust suppression modes, achieving maximum total and respirable dust suppression efficiencies of 87.39% and 86.68%. The results demonstrate the feasibility of coupling mechanical airflow with Venturi entrainment and support subsequent field-scale validation. Full article

Background: Exposure to respirable crystalline silica dust remains a significant occupational health challenge in the Southern African Development Community region, leading to high incidences of silicosis and pulmonary tuberculosis, particularly among mining workers. This study evaluated the knowledge, attitudes, and practices (KAP) of mineworkers regarding silica dust risks across Lesotho, Malawi, Mozambique, and Zambia. Methods: A cross-sectional analytical study was conducted involving 1440 mineworkers exposed to silica dust in mines across four SADC countries. Data were collected using structured questionnaires covering socio-demographic traits and knowledge, attitude, and practices. Data analysis was conducted using Stata version 18. Results: While 91% of participants exhibited adequate knowledge and 88% demonstrated acceptable practices, 51% maintained negative safety attitudes. Knowledge scores were positively correlated with company training (r = 0.386). However, a “Training Paradox” emerged in the regression model: compulsory company training was significantly associated with a 1.20-unit decrease in practice scores, whereas external training and higher education levels (+2.98 units) predicted improved compliance. Technicians and younger workers were identified as higher-risk cohorts. Conclusions: The findings suggest that top-down mandatory training may trigger psychological reactance, undermining behavioural safety. To mitigate silica-related diseases, industry stakeholders should transition toward participatory, role-specific safety interventions that prioritize worker autonomy and cognitive engagement over administrative compliance. Full article

The wettability of dust is fundamental to its dispersion and control in mining operations. Current research, however, focuses largely on isolated properties, leaving the synergistic mechanisms of multi-scale factors-such as particle size, morphology, and surface chemistry-poorly understood. This study integrates field measurements, laboratory characterization, and theoretical analysis to investigate the spatial distribution and wetting behavior of dust in fully mechanized mining faces. The results show that respirable dust preferentially accumulated in mechanically disturbed and personnel-exposure zones. At the shearer operator’s station, respirable dust concentrations reached 328.6 mg/m³ in Mine A and 278.4 mg/m³ in Mine B, which were 1.8 and 1.6 times higher than those at the shearer cutting point, respectively. Mine A dust also showed poorer wettability, with a higher water contact angle of 148.9° ± 2.1° compared with 134.7° ± 1.8° for Mine B, mainly due to its larger agglomerates, rougher surface morphology, and more hydrophobic surface chemistry. Accordingly, targeted development pathways for spray and foam technologies are outlined, including compound wetting agents and micro-nano enhanced foaming systems. The integrated multi-scale framework linking concentration, particle size, morphology, surface chemistry, and wettability provide an application-oriented basis for understanding coal mine dust behavior and for supporting more precise and intelligent dust-control strategies. Full article

Mining activities are characterised by a multiplicity of inherent occupational hazards. Exposure to mineral dust such as silica, asbestos, and coal dust is common in mining, leading to pneumoconiosis. Exposure to respirable silica-containing dust is one of the common respiratory hazards associated with adverse health effects such as silicosis, lung cancer, renal failure, scleroderma, systemic lupus erythematosus (SLE) and chronic obstructive pulmonary disease (COPD), to mention but just a few. In southern Africa, there is a rising epidemic of silicosis, human immunodeficiency virus (HIV) and tuberculosis (TB). Excessive exposure to silica-containing dust exacerbates the TB and silicosis epidemic in mining areas. There is poor control of dust exposure and a lack of occupational hygiene assessments of silica dust in mining in southern Africa. In southern Africa, there remains a persistent knowledge gap regarding the extent of occupational exposures to respirable chemical substances, such as silica dust. Consequently, occupational hygiene air monitoring was conducted in mining companies across four low-income Southern Africa Development Community (SADC) countries, Lesotho, Mozambique, Malawi and Zambia, to provide a baseline exposure dataset. The hazardous nature of work associated with mining activities still persists in these low-income countries, with 53% (n = 72) of quarries and 20% (n = 19) of coal mines having respirable quartz exposures exceeding the reference occupational exposure limit (OEL) of 0.1 milligrams per cubic meter (mg/m³). The highest exposure ranges for quartz were recorded in surface aggregate quarries, with the maximum concentration recorded at 2.739 mg/m³. The highest number of air samples (93%, n = 111), which were in compliance with the OEL of 3 mg/m³ for respirable dust, were recorded in the copper, diamond, ruby, cement quarry and gold mines. This exploratory study confirms the variable extent of mineworker exposure to respirable dust and corresponding quartz fractions emanating from different mining activities. The collected exposure data provides a baseline overview of exposures within the mining industry in the SADC region. It also serves as a vital input for future regional exposure surveillance databases, as well as preliminary data for directing future research towards regional exposure prevention initiatives. Full article

Mining practices and operating conditions are continually evolving, and the respirable fraction of coal mine dust is accordingly expected to change in composition and particle characteristics over time. Between the early 2000s and late 2010s, several regulatory and operational changes occurred in U.S. underground coal mining that could plausibly influence respirable coal mine dust (RCMD), including expanded rock-dusting practices, increased emphasis on respirable crystalline silica, and reductions in diesel emissions. This study evaluated temporal differences in RCMD by comparing samples collected in 2003–2005 and 2018–2020 using particle-level scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX). The most consistent temporal change observed was an increase in carbonate particles, consistent with expanded rock-dusting practices. Shifts in coal- and rock-strata-derived dust were observed but were not consistent across regions, and no consistent trend toward finer particle sizes was identified. These results demonstrate the value of particle-level analysis for evaluating changes in RCMD characteristics over time. Full article

Dust pollution induced by blasting during tunnel construction via the drill-and-blast method poses a severe threat to workers’ health and construction safety. To address this issue, a wet chord grid dust removal and purification device adaptable to deep-buried long tunnels was developed in this study. The device integrates dust control and removal functions, featuring mobility, high purification efficiency, and water recycling capability. Through experimental tests, the optimal operating parameters of the system were determined: the dust removal efficiency reached a peak of 94.3% (laboratory optimal value from the basic parameter optimization test) when the frequency of the extraction axial flow fan was set to 30 Hz and the cross-sectional wind speed of the chord grid reached 3.34 m/s. The circulating water tank achieved the optimal water treatment performance under the conditions of a relative buried depth of 0.42 for the water inlet, a volume ratio of 1:2 for the sedimentation area to the clear water area, and a relative baffle height of 0.65. Numerical simulations based on CFD software (2021) revealed that the on-site dust removal efficiency of the device reached 79.86% and 87.9% under the working conditions where the tunnel face was 10 m and 100 m away from the connecting passage, respectively, which are in good agreement with the field measurement results. In the practical application at the Shierpo Tunnel of the Guangxi Tianba Expressway, the device achieved an average total dust removal efficiency of 78.4%, with 81.2% removal efficiency for PM₁₀ and 76.5% for PM_2.5, demonstrating excellent engineering applicability and dust removal performance for respirable dust. This study provides effective technical support and a theoretical basis for improving the construction environment of drill-and-blast tunnels. Full article

The concentration of heavy metals in the environment has been steadily increasing, raising concerns about their adverse effects on ecosystems and human health. Fine-grained particulate matter is of particular concern due to its enhanced mobility, bioavailability, and potential for inhalation exposure. Facilities involved in the mechanical processing of electronic waste (e-waste) represent a significant potential source of metal-containing fine particles. In this study, crushed e-waste components containing precious metals were separated into particle-size fractions ranging from 3.0 to 0.15 mm using a vibratory sieving system. The elemental composition of the individual fractions was determined by energy-dispersive X-ray fluorescence spectrometry (ED-XRF), while the spatial distribution of selected metals in fine fractions was further investigated using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM–EDS). The results demonstrate that e-waste contains a wide range of heavy non-ferrous metals whose distribution is strongly dependent on particle size. A pronounced enrichment of metals was observed in the finest fractions, particularly below 0.25 mm. Compared to the coarse fraction (>3 mm), the zinc concentration increased by approximately one order of magnitude, while chromium, nickel, and cadmium exhibited increases of up to approximately 20-fold. Lead showed particularly high enrichment, reaching approximately 2 wt.% in the finest fraction (<0.15 mm), corresponding to nearly fiftyfold enrichment relative to the coarse fraction. Tin concentrations also increased markedly, in some cases by up to two orders of magnitude. Trace amounts of arsenic and selenium were detected in the finest fractions, whereas mercury was not detected. The combined ED-XRF and SEM–EDS results confirm that fine-grained e-waste fractions are the dominant carriers of hazardous metals and respirable particles generated during mechanical processing. These findings highlight the dual character of fine fractions as both a critical environmental and occupational risk and a potentially valuable secondary resource. The study emphasizes the importance of controlled handling, effective dust management, and targeted processing strategies to minimize human exposure while enabling efficient recovery of valuable metals from e-waste. Full article

Open-air asphalt milling generates hazardous respirable crystalline silica (RCS), posing severe risks to operators of legacy machines lacking enclosed cabs. This study evaluates a novel, standalone retrofit water spray system designed to intercept fugitive dust. Field validation across 11 road maintenance sites involved particle characterization and paired system-off/on exposure monitoring. Results indicated a Mass Median Aerodynamic Diameter (MMAD) of 6.12 µm, confirming the efficacy of fine-atomizing nozzles (0.3 mm) for capturing respirable fractions. The system achieved RCS suppression efficiencies ranging from 60% to over 85% under low-to-moderate wind conditions (<2.5 m/s). A comparative analysis revealed no significant performance gain from larger 0.5 mm nozzles, supporting the use of smaller orifices for optimal water conservation. However, suppression efficacy degraded significantly when crosswinds exceeded 2.5 m/s, indicating a potential operational boundary. This retrofit solution provides a scientifically validated, cost-effective engineering control for reducing occupational silica exposure in aging road maintenance fleets. Full article

Welding fumes in the shipbuilding industry severely threaten workers’ health. This study systematically investigated welding fume exposure in a Chinese shipyard, analyzing mass concentration, particle size distribution, and harmful metal content using data from 2015. Differences were observed across welding sites and processes. Confined spaces and gas metal arc welding (GMAW) were associated with significantly higher exposure levels. Welding fumes were dominated by particles smaller than 1.00 μm, a distribution influenced by welding site, distance from the welding spot, and process. Iron (Fe) and manganese (Mn) were the predominant metal components, with concentrations significantly higher in respirable dust than in total dust. Risk assessment indicated minimal non-cancer hazards for Fe, zinc, and copper. However, Mn posed the predominant risk (Hazard Quotient >> 1), while nickel (Ni) and chromium (Cr) also exceeded safety thresholds at most points. Consequently, confined spaces and GMAW should be prioritized as key control targets in shipyards, as respirable dust rich in metal-bearing particles poses greater health risks. Therefore, China urgently requires the establishment of specific occupational exposure limits for respirable welding fumes. Additionally, personal sampling is more focused and efficient than area sampling for precise occupational health risk assessment due to the greater mobility of welding operations. Full article

Airborne organic dust has rarely been subject to immunotoxicological analysis. A pilot study was undertaken to link exposure metrics (respirable crystalline silica (RCS), bacteria, fungi, endotoxins (END), peptidoglycans (PGN), (1 → 3)-β-D-glucans (GLU)) with in vitro cytotoxicity and cytokine responses based on analysis of airborne organic dust samples collected during a single work shift at six different facilities. The A549 and BEAS-2B cell lines were used to assess cytotoxicity and proinflammatory cytokine release. The general linear model (GLM) and taxonomic linear ordering were used to identify key determinants and rank facilities by the hazard level they pose. The highest cytotoxicity of organic dust was observed at the sewage treatment plant, while the lowest was at the poultry farm. The most hazardous agents present in organic dust included RCS, aerobic bacteria, fungi, PGN, and GLU. They significantly affected cytokine release, particularly of IL-6 and IL-8. The use of a synthetic measure showed that inhalable organic dust from the composting plant presented the highest potential to induce adverse effects on human health, while the lowest one was characterized by the biomass-fired power plant samples. The open-ended statistical method can significantly increase awareness of occupational hazards and promote more responsible protection for exposed workers. Full article

Workers’ exposure to silica dust is a global occupational and public health concern and is particularly prevalent in Southern Africa, mainly because of inadequate dust control measures. It is worsened by the high prevalence of HIV/AIDS, which exacerbates tuberculosis and other occupational lung diseases. The prevalence of silicosis in the region ranges from 9 to 51%; however, silica dust exposure levels and controls, especially in the informal mining sector, particularly in artisanal small-scale mines (ASMs), leave much to be desired. This is important because silicosis is incurable and can only be eliminated by preventing worker exposure. Additionally, several studies have indicated inadequate occupational health and safety policies, weak inspection systems, inadequate monitoring and control technologies, and inadequate occupational health and hygiene skills. Furthermore, there is a near-absence of silica dust analysis laboratories in southern Africa, except in South Africa. This protocol aims to systematically evaluate the effectiveness of respirable dust and respirable crystalline silica dust exposure evaluation and control methodology for the mining industry. The study will entail testing the effectiveness of current dust control measures for controlling microscale particles using various exposure dose metrics, such as mass, number, and lung surface area concentrations. This will be achieved using a portable Fourier transform infrared spectroscope (FTIR) (Nanozen Industries Inc., Burnaby, BC, Canada), the Nanozen DustCount, which measures both the mass and particle size distribution. The surface area concentration will be analysed by inputting the particle size distribution (PSD) results into the Multiple-Path Particle Dosimetry Model (MPPD) to estimate the retained and cleared doses. The MPPD will help us understand the sub-micron dust deposition and the reduction rate using the controls. To the best of our knowledge, the proposed approach has never been used elsewhere or in our settings. The proposed approach will reduce dependence on highly skilled individuals, reduce the turnaround sampling and analysis time, and provide a reference for regional harmonised occupational exposure limit (OEL) guidelines as a guiding document on how to meet occupational health, safety and environment (OHSE) requirements in ASM settings. Therefore, the outcome of this study will influence policy reforms and protect hundreds of thousands of employees currently working without any form of exposure prevention or protection. Full article

Respirable quartz and dust exposures in dusty façade renovation work tasks were investigated. The presumption was that dust-producing work tasks can be performed safely, keeping exposures low, with practical, easily available methods to control dust emissions and exposure. The aim was to identify deficiencies in exposure management and compare exposure limiting methods to find out how to minimize dust emissions and exposures. Average respirable quartz and dust exposures from the 31 work situations, encompassing nine work tasks studied, were 0.082 and 1.3 mg/m³, respectively. Both values exceed the OEL in Finland, pointing to severe deficiencies in managing exposures. All tasks could, however, be executed safely, keeping exposures low. This often required using respirators while working inside façade covers or close to dust emissions. Other key things when planning exposure maintenance were the following: using water sprays and tool-specific exhausts vents; opening façade cover ventilation apertures; ensuring that non-participants in dusty work tasks are not exposed; working upwind from dust emissions; using pre-blended plaster; using grinders with extension handles; replacing diamond saws and angle grinders with hydraulic cutters when dismantling balcony elements; executing façade jackhammering with robots installed on lifting platforms prior to installing scaffolds and façade covers; detaching façade covers from the clean side; and using lifting platforms. Full article

Occupational exposure to respirable coal mine dust remains a significant health risk, especially for underground workers. Rapid dust monitoring methods are sought to support timely identification of hazards and corrective actions. Recent research has investigated how optical light microscopy (OLM) with automated image processing might meet this need. In laboratory studies, this approach has been demonstrated to classify particles into three primary classes—coal, silicates and carbonates. If the same is achievable in the field, results could support both hazard monitoring and dust source apportionment. The objective of the current study is to evaluate the performance of OLM with image processing to classify real coal mine dust particles, employing scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) as a reference method. The results highlight two possible challenges for field implementation. First, particle agglomeration can effectively yield mixed particles that are difficult to classify, so integration of a dispersion method into the dust collection or sample preparation should be considered. Second, optical differences can exist between dust particles used for classification model development (i.e., typically generated in the lab from high-purity materials) versus real mine dust, so our results demonstrate the necessity of site-specific model calibration. Full article

This article delineates the outcomes of a comprehensive analysis of occupational conditions in coal mining, focusing on dust exposure. A multifaceted model is proposed for the holistic evaluation of occupational environments, integrating risk assessment methodologies and decision-making frameworks within a risk-based paradigm. Risk assessment involved pairwise comparison, T. Saaty’s Analytic Hierarchy Process, a pessimistic decision-making approach, and fuzzy set membership functions. Correlations were established between respiratory disease risk among open pit coal mine workers and dust generation sources at the project design phase. The risk values were then validated using source attributes and particle physicochemical parameter analysis, including disperse composition and morphology. The risk assessment identified haul roads as a predominant factor in occupational disease pathogenesis, demonstrating a calculated risk level of R = 0.512. The dispersed analysis indicated the prevalence of PM1.0 and submicron particles (≤1 µm) with about 77% of the particle count, the mass distribution showed the respirable fraction (1–5 µm) comprising up to 50% of the total dust mass. Considering in situ monitoring data and particulate morphology analysis haul roads (R = 0.281) and the overburden face (R = 0.213) were delineated as primary targets for the implementation of enhanced health and safety interventions. While most critical at the design stage amidst data scarcity and exposure uncertainty, the approach permits subsequent refinement of occupational risks during operations through the incorporation of empirical monitoring data. Full article