Characterization of ambient particles size in workplace of manufacturing physical fitness equipments

Study on the soluble and insoluble fume and hexavalent chromium emitted from a new covered electrode with micro and nano sized-sodium and potassium titanate-based flux

The present study discusses the effect of the addition of nano-sized arc stabilizing materials on fume emissions and its solubility characteristics. Micro and nano-sized sodium/potassium titanates were added to the SMAW electrode flux as a substitute for the conventional sodium and potassium silicate compounds. The total and soluble metal concentration of fumes from the newly developed electrodes were estimated and compared with that of commercially available electrodes. The estimation of fume formation rate and breathing zone concentration of fumes followed the ISO 15011-1 and ISO 10882-1 standard. An average 50% reduction in the soluble fraction of fumes was observed from the electrodes containing micro-sized potassium-titanate compounds, and the reduction was further improved by 60% when nano-sodium titanate was added to the flux. Whereas, the reduction in soluble metal concentration for potassium titanate coated electrodes were 45% and 55%, in that order, for their micro and nano-structured forms. The soluble fraction of hexavalent chromium from the electrodes containing 100% nano sodium/potassium titanates was reduced up to 50% in each impactor stage. The inclusion of nano-sized sodium titanate in the flux resulted in a reduction in fume formation rate up to 55% and breathing zone concentration of fumes by 58% compared to the conventional sodium silicate coated electrodes. The electrode assaying 100% nano-potassium titanate showed a reduction of 59% in fume formation rate and 61% in breathing zone concentration compared to that of conventional potassium silicate-coated electrodes.

Modelled lung deposition and retention of welding fume particles in occupational scenarios: a comparison to doses used in vitro

Translating particle dose from in vitro systems to relevant human exposure remains a major challenge for the use of in vitro studies in assessing occupational hazard and risk of particle exposure. This study aimed to model the lung deposition and retention of welding fume particles following occupational scenarios and subsequently compare the lung doses to those used in vitro. We reviewed published welding fume concentrations and size distributions to identify input values simulating real-life exposure scenarios in the multiple path particle dosimetry (MPPD) model. The majority of the particles were reported to be below 0.1 μm and mass concentrations ranged between 0.05 and 45 mg/m3. Following 6-h exposure to 5 mg/m3 with a count median diameter of 50 nm, the tracheobronchial lung dose (0.89 µg/cm2) was found to exceed the in vitro cytotoxic cell dose (0.125 µg/cm2) previously assessed by us in human bronchial epithelial cells (HBEC-3kt). However, the tracheobronchial retention decreased rapidly when no exposure occurred, in contrast to the alveolar retention which builds-up over time and exceeded the in vitro cytotoxic cell dose after 1.5 working week. After 1 year, the tracheobronchial and alveolar retention was estimated to be 1.15 and 2.85 µg/cm2, respectively. Exposure to low-end aerosol concentrations resulted in alveolar retention comparable to cytotoxic in vitro dose in HBEC-3kt after 15-20 years of welding. This study demonstrates the potential of combining real-life exposure data with particle deposition modelling to improve the understanding of in vitro concentrations in the context of human occupational exposure.

Sequential Multiscale Simulation of a Filtering Facepiece for Prediction of Filtration Efficiency and Resistance in Varied Particulate Scenarios

This study explores a novel approach of multiscale modeling and simulation to characterize the filtration behavior of a facepiece in varied particulate conditions. Sequential multiscale modeling was performed for filter media, filtering facepiece, and testing setup. The developed virtual models were validated for their morphological characteristics and filtration performance by comparing with the data from the physical experiments. Then, a virtual test was conducted in consideration of a time scale, simulating diverse particulate environments with different levels of particle size distribution, particle concentration, and face velocity. An environment with small particles and high mass concentration resulted in a rapid buildup of resistance, reducing the service life. Large particles were accumulated mostly at the entrance of the filter layer, resulting in a lower penetration and slower buildup of resistance. This study is significant in that the adopted virtual approach enables the prediction of filtration behavior and service life, applying diverse environmental conditions without involving the costs of extra setups for the physical experiments. This study demonstrates a novel and economic research method that can be effectively applied to the research and development of filters.

Airborne Occupational Exposures and Lung Function in the Lifelines Cohort Study

Rationale: The association between airborne occupational exposures and lung function level is inconsistent in the general population. Moreover, little is known about the association between occupational exposures and annual lung function decline.Objectives: We investigated the association between occupational exposures and lung function level and annual lung function decline in the population-based Lifelines cohort study.Methods: We included 55,631 adults with baseline spirometry and reliable job code-13,759 of these subjects were aged ≥30 years and underwent spirometry again after 4.5 years of follow-up. Occupational exposures in the current or last-held job at baseline were estimated with the ALOHA+ job-exposure matrix. Linear regression analyses adjusted for covariates were used to test the association between each occupational exposure-biological dust, mineral dust, gases and fumes, pesticides, solvents, and metals-and lung function level and annual lung function decline. Interactions were used to test effect modification by sex or smoking.Results: Exposures to biological dust, mineral dust, gases and fumes, insecticides, fungicides, and aromatic solvents were associated with a lower lung function level at baseline. The effects were larger in males and smokers compared with females and nonsmokers, respectively. However, no association between occupational exposures and the rate of annual lung function decline was found between baseline and follow-up.Conclusions: In this study, airborne occupational exposures are associated with lower lung function level but not with a faster lung function decline. These negative effects are more pronounced among males and smokers.

Bibliometric Analysis of Fitness Equipment: How Scientific Focuses Affect Life-Cycle Approaches and Sustainable Ways of Development

Research Question: Although fitness equipment is recognised worldwide as a tool for physical activities and a sustainable result in optimizing human movements within a wide range of environments, the state of the art and scientific advances have not been analysed from a bibliometric point of view. Research Methods: Using descriptive bibliometric software, this study examined the scientific production, and the most prolific authors, articles, and institutions. Bibliometric maps were used to visualise the content of published articles and to determine the most prolific terms, co-citation, and co-authorship. Results and Findings: A total of 678 original papers were retrieved from 447 journals in Web of Science®. The Journal of Strength and Conditioning Research had the highest number of articles (25), while the American Journal of Preventive Medicine the highest number of global citations (656). Citation and co-authorship networks were defined. Implications: Research on fitness equipment is still in an early maturation stage with 30 years of scientific development in its timeline. Fitness equipment and its related fields of application could represent a real step into a more sustainable balance between the economic, environmental, and social spheres.