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There is an increasing need to evaluate concentrations of nanoparticles in occupational settings due to their potential negative health effects. The Nanoparticle Respiratory Deposition (NRD) personal sampler was developed to collect nanoparticles separately from larger particles in the breathing zone of workers, while simultaneously providing a measure of respirable mass concentration. This study compared concentrations measured with the NRD sampler to those measured with a nano Micro Orifice Uniform-Deposit Impactor (nanoMOUDI) and respirable samplers in three workplaces. The NRD sampler performed well at two out of three locations, where over 90% of metal particles by mass were submicrometer particle size (a heavy vehicle machining and assembly facility and a shooting range). At the heavy vehicle facility, the mean metal mass concentration of particles collected on the diffusion stage of the NRD was 42.5 ± 10.0 µg/m3, within 5% of the nanoMOUDI concentration of 44.4 ± 7.4 µg/m3. At the shooting range, the mass concentration for the diffusion stage of the NRD was 5.9 µg/m3, 28% above the nanoMOUDI concentration of 4.6 µg/m3. In contrast, less favorable results were obtained at an iron foundry, where 95% of metal particles by mass were larger than 1 µm. The accuracy of nanoparticle collection by NRD diffusion stage may have been compromised by high concentrations of coarse particles at the iron foundry, where the NRD collected almost 5-fold more nanoparticle mass compared to the nanoMOUDI on one sampling day and was more than 40% different on other sampling days. The respirable concentrations measured by NRD samplers agreed well with concentrations measured by respirable samplers at all sampling locations. Overall, the NRD sampler accurately measured concentrations of nanoparticles in industrial environments when concentrations of large, coarse mode, particles were low.

Welding fume is a complex mixture containing ultra-fine particles in the nanometer range. Rather than being in the form of a singular sphere, due to the high particle concentration, welding fume particles agglomerate into long straight chains, branches, or other forms of compact shapes. Understanding the transport and deposition of these nano-agglomerates in human respiratory systems is of great interest as welding fumes are a known health hazard. The neurotoxin manganese (Mn) is a common element in welding fumes. Particulate Mn, either as soluble salts or oxides, that has deposited on the olfactory mucosa in human nasal airway is transported along the olfactory nerve to the olfactory bulb within the brain. If this Mn is further transported to the basal ganglia of the brain, it could accumulate at the part of the brain that is the focal point of its neurotoxicity. Accounting for various dynamic shape factors due to particle agglomeration, the current computational study is focused on the exposure route, the deposition pattern, and the deposition efficiency of the inhaled welding fume particles in a realistic human nasal cavity. Particular attention is given to the deposition pattern and deposition efficiency of inhaled welding fume agglomerates in the nasal olfactory region. For particles in the nanoscale, molecular diffusion is the dominant transport mechanism. Therefore, Brownian diffusion, hydrodynamic drag, Saffman lift force, and gravitational force are included in the model study. The deposition efficiencies for single spherical particles, two kinds of agglomerates of primary particles, two-dimensional planar and straight chains, are investigated for a range of primary particle sizes and a range of number of primary particles per agglomerate. A small fraction of the inhaled welding fume agglomerates is deposited on the olfactory mucosa, approximately in the range 0.1-1%, and depends on particle size and morphology. The strong size dependence of the deposition

Welding is a widely used method to join two pieces of stainless steel. Since it produces a large amount of fume during the process, it can cause adverse health effects. The welding fume particles contain many elements. Among them Cr, Mn and Ni are of concern. These three elements can cause diseases if inhaled by humans, especially Cr(VI). In this project, welding fume particles are collected during welding of different stainless steel grades (austenitic AISI 304L and duplex LDX2101). Furthermore, different welding types (manual metal arc welding and metal active gas welding), shielding gas (MISON 2, MISON 18 and CORGON 18) and welding electrodes were varied (solid and flux cored wire). The particles were tested by scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry and atomic absorption spectroscopy. The composition of the particles was measured and the surface chemical speciation estimated. In addition, metal release (Fe, Cr, Mn, and Ni) in phosphate buffered saline solution (pH 7.4, 37℃, 24h) from the particles was tested. Fe, Cr and Mn were found on the surface of the particles and released to different extent in the phosphate buffered saline solution (dominated by Cr).

Welding is a widely used method to join two pieces of stainless steel. Since it produces a large amount of fume during the process, it can cause adverse health effects. The welding fume particles contain many elements. Among them Cr, Mn and Ni are of concern. These three elements can cause diseases if inhaled by humans, especially Cr(VI). In this project, welding fume particles are collected during welding of different stainless steel grades (austenitic AISI 304L and duplex LDX2101). Furthermore, different welding types (manual metal arc welding and metal active gas welding), shielding gas (MISON 2, MISON 18 and CORGON 18) and welding electrodes were varied (solid and flux cored wire). The particles were tested by scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry and atomic absorption spectroscopy. The composition of the particles was measured and the surface chemical speciation estimated. In addition, metal release (Fe, Cr, Mn, and Ni) in phosphate buffered saline solution (pH 7.4, 37℃, 24h) from the particles was tested. Fe, Cr and Mn were found on the surface of the particles and released to different extent in the phosphate buffered saline solution (dominated by Cr).

Workplace exposure to nanoparticles from gas metal arc welding (GMAW) process in an automobile manufacturing factory was investigated using a combination of multiple metrics and a comparison with background particles. The number concentration (NC), lung-deposited surface area concentration (SAC), estimated SAC and mass concentration (MC) of nanoparticles produced from the GMAW process were significantly higher than those of background particles before welding (P < 0.01). A bimodal size distribution by mass for welding particles with two peak values (i.e., 10,000-18,000 and 560-320 nm) and a unimodal size distribution by number with 190.7-nm mode size or 154.9-nm geometric size were observed. Nanoparticles by number comprised 60.7% of particles, whereas nanoparticles by mass only accounted for 18.2% of the total particles. The morphology of welding particles was dominated by the formation of chain-like agglomerates of primary particles. The metal composition of these welding particles consisted primarily of Fe, Mn, and Zn. The size distribution, morphology, and elemental compositions of welding particles were significantly different from background particles. Working activities, sampling distances from the source, air velocity, engineering control measures, and background particles in working places had significant influences on concentrations of airborne nanoparticle. In addition, SAC showed a high correlation with NC and a relatively low correlation with MC. These findings indicate that the GMAW process is able to generate significant levels of nanoparticles. It is recommended that a combination of multiple metrics is measured as part of a well-designed sampling strategy for airborne nanoparticles. Key exposure factors, such as particle agglomeration/aggregation, background particles, working activities, temporal and spatial distributions of the particles, air velocity, engineering control measures, should be investigated when measuring workplace exposure to nan

Examensarbetet har utförts vid ABB Power Transformers i Ludvika i plåtverkstaden, där stora transformatorlådor svetsas ihop. Tillsammans med vår handledare på företaget utformades ämnet för examensarbetet att bedöma luftkvalitet och arbetsmiljö vid punktsvetsning i koppar. Det fanns misstanke om att exponeringen för koppar var hög och en utvärdering av luftkvaliteten behövde därmed göras. Ingen tidigare exponeringsmätning vid svetsning i koppar har genomförts i plåtverkstaden. Syftet med examensarbetet var att utvärdera och komma fram till tre åtgärdsförslag för att skapa en bättre arbetsmiljö vid punktsvetsning samt att begränsa exponeringen av svetsrök som bildas vid svetsning i koppar. Tre åtgärder var företagets önskemål. En exponeringsmätning av luftföroreningar vid svetsning i koppar gjordes för att kontrollera halten av ämnen i svetsröken, i förhållande till de hygieniska nivågränsvärdena. Exponeringsmätningen gjordes personburet. Dessutom gjordes stationär mätning samt mätning med direktvisande instrument. Användning av skyddsutrustning och ventilationen granskades. I samband med exponeringsmätning genomfördes intervjuer. Resultatet av exponeringsmätningarna har visat att det hygieniska nivågränsvärdet för koppar överstegs kraftigt vid punktsvetsning med MIGsvetsmetoden. Nivågränsvärdet för koppar är 0,2 mg/m3 och det högsta uppmätta värdet uppgick till 1,05 mg/m3, mätt utanför svetsvisiret. Utifrån observationer om användning av skyddsutrustning har det noterats att det finns tillgång till lämplig skyddsutrustning men att den inte används i den utsträckning som den borde. De tre åtgärdsförslag vi utvecklade är att; (1) införa rutiner för filterbyte med jämna mellanrum, (2) börja använda integrerade utsug i större utsträckning samt att (3) förbättra lokalens ventilation genom att installera deplacerande ventilation. De två beräknade åtgärdskostnaderna, åtgärd (1) och (2), följer företagets PayOff-princip på 3 år. Examensarbetet ska bidra till att alla, This thesis has been carried out at ABB Power Transformers in Ludvika at the plate shop, where large transformer boxes are welded together. The topic of the thesis was formulated together with our supervisor at the company, to assess air quality and work environment at the spot welding of copper. Copper exposure was suspected to be high, and an evaluation of air quality was needed. No previous exposure measurements when welding in copper have been made in the plate shop. The purpose of this study was to evaluate and come up with three proposals for actions to create a better working environment for spot welding as well as to limit exposure to welding fumes generated during welding of copper. An exposure measurement of air pollutants during welding of copper was done to evaluate copper exposure compared to threshold limit values of substances in welding fume. Exposure measurements were made with personal monitors. In addition, measurement with stationary equipment and measurement with directreading instruments. The use of protective equipment and ventilation were studied. In connection with measurements interviews were made. The results of exposure measurements showed that the occupational exposure limit value for copper was exceeded considerably during the spot welding with the MIG welding process. The threshold limit value of copper is 0,2 mg/m3 and the highest value measured was 1,05 mg/m3, measured outside the welding shield. Based on observations on the use of personal protective equipment it has been noted that protective equipment is available but not used to desired extent. Three control actions are proposed; (1) routines to change the respiratory protective equipment filter regularly, (2) start using local exhaust integrated in the welding gun to a greater extent and (3) improve the ventilation in the plate shop by installing displacement ventilation. The calculated costs for two of the actions, action (1) and (2), fulfill the company's payoff principle

Examensarbetet har utförts vid ABB Power Transformers i Ludvika i plåtverkstaden, där stora transformatorlådor svetsas ihop. Tillsammans med vår handledare på företaget utformades ämnet för examensarbetet att bedöma luftkvalitet och arbetsmiljö vid punktsvetsning i koppar. Det fanns misstanke om att exponeringen för koppar var hög och en utvärdering av luftkvaliteten behövde därmed göras. Ingen tidigare exponeringsmätning vid svetsning i koppar har genomförts i plåtverkstaden. Syftet med examensarbetet var att utvärdera och komma fram till tre åtgärdsförslag för att skapa en bättre arbetsmiljö vid punktsvetsning samt att begränsa exponeringen av svetsrök som bildas vid svetsning i koppar. Tre åtgärder var företagets önskemål. En exponeringsmätning av luftföroreningar vid svetsning i koppar gjordes för att kontrollera halten av ämnen i svetsröken, i förhållande till de hygieniska nivågränsvärdena. Exponeringsmätningen gjordes personburet. Dessutom gjordes stationär mätning samt mätning med direktvisande instrument. Användning av skyddsutrustning och ventilationen granskades. I samband med exponeringsmätning genomfördes intervjuer. Resultatet av exponeringsmätningarna har visat att det hygieniska nivågränsvärdet för koppar överstegs kraftigt vid punktsvetsning med MIGsvetsmetoden. Nivågränsvärdet för koppar är 0,2 mg/m3 och det högsta uppmätta värdet uppgick till 1,05 mg/m3, mätt utanför svetsvisiret. Utifrån observationer om användning av skyddsutrustning har det noterats att det finns tillgång till lämplig skyddsutrustning men att den inte används i den utsträckning som den borde. De tre åtgärdsförslag vi utvecklade är att; (1) införa rutiner för filterbyte med jämna mellanrum, (2) börja använda integrerade utsug i större utsträckning samt att (3) förbättra lokalens ventilation genom att installera deplacerande ventilation. De två beräknade åtgärdskostnaderna, åtgärd (1) och (2), följer företagets PayOff-princip på 3 år. Examensarbetet ska bidra till att alla, This thesis has been carried out at ABB Power Transformers in Ludvika at the plate shop, where large transformer boxes are welded together. The topic of the thesis was formulated together with our supervisor at the company, to assess air quality and work environment at the spot welding of copper. Copper exposure was suspected to be high, and an evaluation of air quality was needed. No previous exposure measurements when welding in copper have been made in the plate shop. The purpose of this study was to evaluate and come up with three proposals for actions to create a better working environment for spot welding as well as to limit exposure to welding fumes generated during welding of copper. An exposure measurement of air pollutants during welding of copper was done to evaluate copper exposure compared to threshold limit values of substances in welding fume. Exposure measurements were made with personal monitors. In addition, measurement with stationary equipment and measurement with directreading instruments. The use of protective equipment and ventilation were studied. In connection with measurements interviews were made. The results of exposure measurements showed that the occupational exposure limit value for copper was exceeded considerably during the spot welding with the MIG welding process. The threshold limit value of copper is 0,2 mg/m3 and the highest value measured was 1,05 mg/m3, measured outside the welding shield. Based on observations on the use of personal protective equipment it has been noted that protective equipment is available but not used to desired extent. Three control actions are proposed; (1) routines to change the respiratory protective equipment filter regularly, (2) start using local exhaust integrated in the welding gun to a greater extent and (3) improve the ventilation in the plate shop by installing displacement ventilation. The calculated costs for two of the actions, action (1) and (2), fulfill the company's payoff principle

Linear mixed models were used to analyze data compiled from international sources to simultaneously estimate the fixed effects, associated with process characteristics and sampling regimen, and the variance components, associated with the random effects. The fixed effects explained 55% and 49% of variation in TP and Mn exposures, respectively. The country, industry/trade, ventilation condition, type of work/welding process, and material employed appeared to be the major factors affecting exposures to TP and Mn. Measurements in the U.S. were generally higher than those in other countries. Exposure to TP was 64% higher in enclosed spaces and 42% lower with local exhaust ventilation, was higher among boiler makers, and was higher when a mild-steel base metal was used. Exposure to Mn was 318% higher in enclosed spaces and 67% lower when local exhaust ventilation was present. The measured Mn air concentration was significantly related to the composition of the consumables, but not to the base metal. Resistance welding produced significantly lower TP and Mn exposures compared to other welding processes. After controlling for fixed effects, variance components between groups and between individual workers within a group were reduced by 89% and 57% for TP, and 75% and 63% for Mn, respectively. The within-worker variance component in Mn exposure was three times higher than that of TP, indicating that day-to-day and within-day variations in TP and Mn exposures were influenced by different factors that were not captured equally well by the mixed models for these two contaminants. Interestingly, exposures to TP and Mn had not changed over the 40 years of observation. The estimated probabilities of exceeding occupational exposure limits were very high (generally much greater than 10%) for both agents. Welding exposures to TP and Mn vary considerably across the world and across occupational groups. Exposures to both contaminants have been and continue to be unacceptably high in m

Linear mixed models were used to analyze data compiled from international sources to simultaneously estimate the fixed effects, associated with process characteristics and sampling regimen, and the variance components, associated with the random effects. The fixed effects explained 55% and 49% of variation in TP and Mn exposures, respectively. The country, industry/trade, ventilation condition, type of work/welding process, and material employed appeared to be the major factors affecting exposures to TP and Mn. Measurements in the U.S. were generally higher than those in other countries. Exposure to TP was 64% higher in enclosed spaces and 42% lower with local exhaust ventilation, was higher among boiler makers, and was higher when a mild-steel base metal was used. Exposure to Mn was 318% higher in enclosed spaces and 67% lower when local exhaust ventilation was present. The measured Mn air concentration was significantly related to the composition of the consumables, but not to the base metal. Resistance welding produced significantly lower TP and Mn exposures compared to other welding processes. After controlling for fixed effects, variance components between groups and between individual workers within a group were reduced by 89% and 57% for TP, and 75% and 63% for Mn, respectively. The within-worker variance component in Mn exposure was three times higher than that of TP, indicating that day-to-day and within-day variations in TP and Mn exposures were influenced by different factors that were not captured equally well by the mixed models for these two contaminants. Interestingly, exposures to TP and Mn had not changed over the 40 years of observation. The estimated probabilities of exceeding occupational exposure limits were very high (generally much greater than 10%) for both agents. Welding exposures to TP and Mn vary considerably across the world and across occupational groups. Exposures to both contaminants have been and continue to be unacceptably high in m

Flow cytometry is a simple analytical technique that identifies, counts, and characterizes cells. The oxidative status of cells is influenced by many exogenous sources, such as occupational exposure to welding fumes. This study evaluated flow cytometry as a method to determine the oxidative status of male welders (n = 15) occupationally exposed to welding fumes. Flow cytometric analysis of reactive oxygen species (ROS) was carried out in peripheral blood mononuclear cells (PBMC) by using the probe 2, 7-dichlorodihydrofluorescein diacetate (DCFH-DA). Lipid peroxidation was measured by the decrease of fluor-DHPE fluorescence and intracellular glutathione (GSH) levels by using mercury orange. All of the parameters were also observed under a confocal microscope. The oxidative stress ratio was calculated from the oxidative damage and the antioxidant capacity to give an accurate account of the cellular oxidative status. ROS and lipid peroxidation levels were elevated by ∼ 87% and ∼ 96%, respectively, and GSH levels lowered ∼ 96% in PBMC of workers exposed to welding fumes compared with non-exposed controls. The oxidative stress ratio was significantly higher (p < 0.001) in the exposed group. Flow cytometry can be useful for the measurement of cellular oxidative stress in somatic cells of workers exposed to welding fumes and other occupational settings. Calculating an oxidative stress index may be useful in predicting disease outcomes and whether preventative control measures are efficient

Flow cytometry is a simple analytical technique that identifies, counts, and characterizes cells. The oxidative status of cells is influenced by many exogenous sources, such as occupational exposure to welding fumes. This study evaluated flow cytometry as a method to determine the oxidative status of male welders (n = 15) occupationally exposed to welding fumes. Flow cytometric analysis of reactive oxygen species (ROS) was carried out in peripheral blood mononuclear cells (PBMC) by using the probe 2, 7-dichlorodihydrofluorescein diacetate (DCFH-DA). Lipid peroxidation was measured by the decrease of fluor-DHPE fluorescence and intracellular glutathione (GSH) levels by using mercury orange. All of the parameters were also observed under a confocal microscope. The oxidative stress ratio was calculated from the oxidative damage and the antioxidant capacity to give an accurate account of the cellular oxidative status. ROS and lipid peroxidation levels were elevated by ∼ 87% and ∼ 96%, respectively, and GSH levels lowered ∼ 96% in PBMC of workers exposed to welding fumes compared with non-exposed controls. The oxidative stress ratio was significantly higher (p < 0.001) in the exposed group. Flow cytometry can be useful for the measurement of cellular oxidative stress in somatic cells of workers exposed to welding fumes and other occupational settings. Calculating an oxidative stress index may be useful in predicting disease outcomes and whether preventative control measures are efficient