Fume Concentration Research Articles

Determination of Informal Sector as Urban Pollution Source : Fume Characterization of Small-scale Manual Metal Arc Welding using Factor Analysis in Bandung City

In developing countries, the informal sector, particularly small-scale welding activities, are considered to be an important contributor to urban air pollution although studies in this sector are limited. This study aims to identify the composition of small-scale welding fume in order to further investigate the effects and set control strategies and urban pollution abatement policies. Breathing zone air samples were collected from 30 mild steel manual metal arc welders and 17 non-welders in Bandung City, West Java, Indonesia. The respirable particulates in air samples were analyzed using gravimetric method, and Instrumental Neutron Activation Analysis (INAA) was employed to identify characteristic of welding fume. It was found that respirable particulates concentration in welders (range : 315.6 and 3,735.93 µgm -3 ; average 1,545.436 µgm -3 ) were significantly higher than in non-welders (range : 41.84 and 1,688.03 µgm -3 ; average : 375.783 µgm -3 ). Welders’ breathing zones contain Fe>Na>K>Mn>Al >Cr>Ti>Cl>Br>I>Zn>Sb>V>Co>Sc; while non-welders’ breathing zones contain Cr>F>Al>Ti>Na>Br>I>Mn>Cl>Co>Zn>Sc. Inter-species correlation analysis conducted using Statgraphic Ver. 4.0 shows that Fe (range : n.d. – 775.19 µgm -3 ; average: 0.1674 µgm -3 ), Co (range : n.d. – 0.51 µgm -3 ; average: 0.000082 µgm -3 ), Mn (range : 0.39 – 148.37 µgm -3 ; average: 0.0374 µgm -3 ), Na (range: 0.17 and 623.85 µgm -3 ; average: 0.0973 µgm -3 ) and K (range : n.d. – 301.15 µgm -3 ; average: 0.0535 µgm -3 ) were emitted from welding activity, and thus are considered as components of welding fume which contribute to urban air pollution. Although welding fume and the identified species in welding fume were still below permissible limit, small-scale welding activities have great potential in emitting higher fume concentration due to due to high variability of welding activities, such as welding frequency, materials being welded, and varied environmental conditions. Received: 5 December 2011; Revised: 17 April 2012; Accepted: 20 April 2012

Task-based exposure assessment of nanoparticles in the workplace

Although task-based sampling is, theoretically, a plausible approach to the assessment of nanoparticle exposure, few studies using this type of sampling have been published. This study characterized and compared task-based nanoparticle exposure profiles for engineered nanoparticle manufacturing workplaces (ENMW) and workplaces that generated welding fumes containing incidental nanoparticles. Two ENMW and two welding workplaces were selected for exposure assessments. Real-time devices were utilized to characterize the concentration profiles and size distributions of airborne nanoparticles. Filter-based sampling was performed to measure time-weighted average (TWA) concentrations, and off-line analysis was performed using an electron microscope. Workplace tasks were recorded by researchers to determine the concentration profiles associated with particular tasks/events. This study demonstrated that exposure profiles differ greatly in terms of concentrations and size distributions according to the task performed. The size distributions recorded during tasks were different from both those recorded during periods with no activity and from the background. The airborne concentration profiles of the nanoparticles varied according to not only the type of workplace but also the concentration metrics. The concentrations measured by surface area and the number concentrations measured by condensation particle counter, particulate matter 1.0, and TWA mass concentrations all showed a similar pattern, whereas the number concentrations measured by scanning mobility particle sizer indicated that the welding fume concentrations at one of the welding workplaces were unexpectedly higher than were those at workplaces that were engineering nanoparticles. This study suggests that a task-based exposure assessment can provide useful information regarding the exposure profiles of nanoparticles and can therefore be used as an exposure assessment tool.

Occupational Exposure to Manganese‐containing Welding Fumes and Pulmonary Function Indices among Natural Gas Transmission Pipeline Welders

The objectives of this study were to evaluate manganese (Mn)-containing welding fumes' exposure, assess urinary Mn as a biomarker for Mn exposure and investigate the correlation of Mn in air, total fumes and urinary Mn with pulmonary function indices in 118 welders and 37 unexposed controls from two regions in Iran, Assaluyeh and Borujen. Air samples were collected on mixed cellulose ester membrane filters in personal air samplers and then analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES) (NIOSH Method 7300). For all participants, urine samples were collected during the entire work shift, and Mn in urine was determined by graphite furnace atomic absorption spectroscopy according to NIOSH Method 8310. Spirometric measurements were also done for participants. The maximum exposures to airborne Mn and total fumes were 0.304 ± 0.256 mg/m(3) and 21.52 ± 9.40 mg/m(3), respectively. The urine Mn levels in the various groups ranged between 0.77 to 7.58 μg/l. The correlation between airborne Mn and urinary Mn was significant for total whole participants. Some values of spirometric indices were statistically lower in welders rather than controls. Our results indicate that many welders have been exposed to higher concentrations of Mn-containing welding fumes. Urinary Mn can be used as a biomarker for Mn exposure. There were weak inverse correlations between Mn-containing welding fumes and pulmonary function indices, and the inverse correlation between urinary Mn with forced vital capacities (FVC) and forced expiratory volume in 1 s (FEV1) was significant.

Work Environments and Exposure to Hazardous Substances in Korean Tire Manufacturing

ObjectivesThe purpose of this study is to evaluate the tire manufacturing work environments extensively and to identify workers' exposure to hazardous substances in various work processes.MethodsPersonal air sampling was conducted to measure polycyclic aromatic hydrocarbons, carbon disulfide, 1,3-butadiene, styrene, methyl isobutyl ketone, methylcyclohexane, formaldehyde, sulfur dioxide, and rubber fume in tire manufacturing plants using the National Institute for Occupational Safety Health Manual of Analytical Methods. Noise, carbon monoxide, and heat stress exposure were evaluated using direct reading instruments. Past concentrations of rubber fume were assessed using regression analysis of total particulate data from 2003 to 2007, after identifying the correlation between the concentration of total particulate and rubber fume.ResultsWorkers were exposed to rubber fume that exceeded 0.6 mg/m3, the maximum exposure limit of the UK, in curing and production management processes. Forty-seven percent of workers were exposed to noise levels exceeding 85 dBA. Workers in the production management process were exposed to 28.1℃ (wet bulb globe temperature value, WBGT value) even when the outdoor atmosphere was 2.7℃ (WBGT value). Exposures to other substances were below the limit of detection or under a tenth of the threshold limit values given by the American Conference of Governmental Industrial Hygienists.ConclusionTo better classify exposure groups and to improve work environments, examining closely at rubber fume components and temperature as risk indicators in tire manufacturing is recommended.

Exposure of healthy subjects with emissions from a gas metal arc welding process: part 3—biological effect markers and lung function

Metal active gas welding (MAG) is a widely-used welding technique resulting in high emissions of welding fume particles. This study investigated whether short-term exposure to these fume particles results in changes in lung function and early stages of inflammatory reactions. Twelve healthy, young male subjects were exposed to MAG fumes for 6 h with three different exposure concentrations in a three-fold cross-over study design. Exposure was performed in the "Aachen Workplace Simulation Laboratory" under controlled conditions with constant fume concentration. Fume concentrations were 0, 1, and 2.5 mg m(-3) in randomized order. Before and after each exposure, spirometry, and impulse oscillometry were performed and breath condensate samples were collected in order to quantify inflammatory markers like Nitrate, Nitrite, Nitrotyrosine, Hydroxyprolin and Malondialdehyde. A significant dependency on the exposure concentration could not be established for any of the endpoint parameters. In healthy, young subjects neither changes in spirometry nor changes in inflammatory markers measured in exhaled breath condensate could be detected after short-term exposure.

Experimental exposure of healthy subjects with emissions from a gas metal arc welding process—part II: biomonitoring of chromium and nickel

The objective of this study was to investigate whether there is a relationship between the external exposure dose of chromium and nickel caused by a metal active gas welding process with a solid high-alloyed steel welding wire and inner exposure of subjects. In order to perform welding fume exposure under controlled and standardized conditions, the investigations were conducted in the "Aachen Workplace Simulation Laboratory". To perform biological monitoring of chromium and nickel, blood and urine samples of 12 healthy male non-smokers who never worked as welders were collected before and after a 6-h exposure to ambient air (0 mg/m(3)) and to welding fumes of a metal active gas welding process once with a concentration of the welding fume of 1 mg/m(3) and once with a concentration of 2.5 mg/m(3). Although the internal exposure to chromium and nickel in this study was comparatively low, the subjects showed significantly increased concentrations of these metals in urine after exposure to welding fume compared to the values at baseline. Moreover, the observed increase was significantly dose dependent for both of the substances. For the biological monitoring of chromium and nickel in urine of subjects exposed to welding fumes, a dependency on exposure dose was seen under standardized conditions after a single exposure over a period of 6 h. Thus, this study contributes to a better understanding of the relationship between ambient and biological exposures from welding fumes and provides a good basis for evaluating future biological threshold values for these metals in welding occupation.

Exposure of healthy subjects with emissions from a gas metal arc welding process: part 1—exposure technique and external exposure

Studies concerning welding fume-related adverse health effects in welders are hampered by the heterogeneity of workplace situations, resulting in complex and non-standardized exposure conditions. In order to carry out welding fume exposure studies under controlled and standardized conditions, the Aachen Workplace Simulation Laboratory was developed. This laboratory consists of an emission room, in which welding fume is produced, and an exposure room in which human subjects are exposed to these fumes. Both rooms are connected by a ventilation system which allows the welding fume concentration to be regulated. Particle mass concentration was measured with a TEOM microbalance and the particle number-size distribution using a Grimm SMPS device. In a study, which is the subject of this paper, it has been shown that welding fume concentration can easily be regulated between 1 and about 3 mg m(-3). The chosen concentration can be kept constant for more than 8 h. However, transport of the particles from the emission room into the exposure room leads to a change in particle size distribution, which is probably due to coagulation of the fraction of smallest particles. The Aachen Workplace Simulation Laboratory is suitable for controlled exposure studies with human subjects.

A Fume Concentration Model of Underground Mine Fire and Its Calculation

In order to obtain fume concentration distribution of underground mine fire spread process, a fume concentration calculation model, which takes into accounts into the effect of the fume's diffusion effect and the transport effect of the airflow, is established with the gradient transfer theory. The corresponding calculation steps are put forward. Then through calculating the fire fume concentration of a typical underground mine, the risk range of certain time after the fire accident can be given according to related standards. The results verify the validity and accuracy of the model and can provide references for the evacuation and rescue of underground mine fire accident.

Surface settlement of cementitious-based materials determined by oedometer testing

The oedometer test is commonly used in soil mechanics to evaluate consolidation of clays and other compressible soils. A research project was undertaken to evaluate the suitability of such test to assess surface settlement of freshly mixed cementitious-based materials. Three series of concrete-equivalent-mortar (CEM) mixtures made with different cement contents, water-to-cementitious materials ratio (w/cm), silica fume, and viscosity-modifying admixture (VMA) were tested. Validation of test results was performed by casting concrete mixtures in a PVC column having 600-mm height and 200-mm diameter. Test results have shown that CEM settlements determined using the oedometer test as well as concrete settlements determined using the 600-mm PVC column are affected quite similarly by the mixture composition. For example, for given consistency, settlement decreases with the increase in cement content, decrease in w/cm, and incorporation of increased concentrations of silica fume or VMA. Statistical analysis was then performed to propose regression models for predicting maximum settlement of concrete through the determination of CEM characteristics.

The Effect of Voltage and Metal Transfer Mode on Particulate Fume Size During the GMAW of Plain Carbon Steel

Particulate welding fumes can enter unciliated airways, or may even be absorbed through the skin, possibly to the detriment of the health of welders. The size and shape of the particulates will determine their ability to infiltrate the human body. Hence, the sensitivity of particulate fume size to welding parameters such as arc voltage (20–36 V) and metal transfer mode (dip, globular and spray) was assessed. Transmission electron microscopy (TEM) imaging was used for determining particulate fume size and it was found to be an accurate, reproducible, and relatively simple technique. The results revealed a higher percentage of ultra fine particulates (i.e. in < 20 nm and 20–40 nm intervals) in ‘low welding voltage’ fume plume compared with ‘high welding voltage’ fume plume. Fundamentally, the fume plume created during dip metal transfer at low welding voltages (20–26 V) had much lower levels of particulate fume concentration compared with spray metal transfer at high welding voltages (30–36 V). TEM also revealed that for the range of welding voltages and metal transfer modes investigated, the particulates produced were predominantly less than 100 nm in diameter and spherical. Spherical particles (< 100 nm) have been reported elsewhere to reach the alveoli in rats and, hence, may be of relevance with respect to the health of welders. Slightly faceted crystalline particulates and fume particle sizes of up to 800 nm in diameter were also observed with TEM. It should be noted that the agglomeration behaviour of these particulates in the fume plume is considered important but not entirely understood. The particle size results suggest that the key to welder safety is to minimize cumulative exposure to particulate fume over their working life, irrespective of the welding parameters used. Innovative fume extraction techniques, clean workshops, automated welding, and low welding fume consumables should all form part of an integrated solution to help ensure the health and well-being of welding personnel.

Total Fume and Metal Concentrations during Welding in Selected Factories in Jeddah, Saudi Arabia

Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder’s health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers’ welding fume exposure levels in some industries in Jeddah, Saudi Arabia. In each factory, the air in the breathing zone within 0.5 m from welders was sampled during 8-hour shifts. Total particulates, manganese, copper, and molybdenum concentrations of welding fumes were determined. Mean values of eight-hour average particulate concentrations measured during welding at the welders breathing zone were 6.3 mg/m3 (Factory 1), 5.3 mg/m3 (Factory 2), 11.3 mg/m3 (Factory 3), 6.8 mg/m3 (Factory 4), 4.7 mg/m3 (Factory 5), and 3.0 mg/m3 (Factory 6). Mean values of airborne manganese, copper, and molybdenum levels measured during welding were in the range of 0.010 mg/m3–0.477 mg/m3, 0.001 mg/m3–0.080 mg/m3 and 0.001 mg/m3–0.058 mg/m3 respectively. Mean values of calculated equivalent exposure values were: 1.50 (Factory 1), 1.56 (Factory 2), 5.14 (Factory 3), 2.21 (Factory 4), 2.89 (Factory 5), and 1.20 (Factory 6). The welders in factories 1, 2, 3, and 4 were exposed to welding fume concentration above the SASO limit value, which may increase the risk of respiratory health problems.

Chronic Obstructive Pulmonary Disease in Iron-steel and Ferrochrome Industry Workers

Metallurgical industry workers in developing countries are often exposed to high concentrations of dusts and fumes that affect pulmonary function. The aim of this cross-sectional study is to assess the prevalence and severity of chronic obstructive pulmonary disease (COPD), the prevalence of symptoms, as well as, the link between work-place air pollution and COPD. A standardized questionnaire was used to collect data about smoking and socioeconomic status, past history of pulmonary diseases, current respiratory symptoms, education, and other variables. We have identified and assessed all risk factors and also have performed measurements of dynamic pulmonary function in 459 subjects - 90% of iron-steel and ferrochrome industry workers. The prevalence of COPD oscillated from 19.6% up to 25.7% while severity varied from mild to very severe. prevalence varied from 12.0% to 46.3% while relative risk for developing COPD was 2.1-5.5 that of non-industry controls. Exposure markers' concentrations: for total suspended particles (TSP) oscillated from 0.375-25.5 mg/m3, particulate matter (PM10) from 0.25 to 10.5 mg/m3, and sulfur dioxide from 0.19-18.69 mg/m3. In majority of cases its average exceeded threshold limit values. Our conclusion was that COPD prevalence and its symptoms are high in the population studied, and that there exists a well established occupational risk between work-place air pollution and COPD.

Diagnosing metal fume fever--an integrated approach

Exposure to high concentrations of zinc oxide fume can cause metal fume fever (MFF). Two cases occurring following the oxy-acetylene cutting of galvanized steel frames are reported. To show that integrated working is valuable as secondary health care staff may not be familiar with MFF. Site visits by Her Majesty's Medical, Health and Safety (H&S) and Specialist Occupational Hygiene Inspectors to gather information and cooperation with occupational health, primary and secondary health care staff to diagnose MFF. Poor exposure control caused metal fume inhalation in these cases. Multidisciplinary working established diagnosis, causation and compliance with H&S legislation. Risk assessments are required to identify health risks and to determine required exposure control measures. Failure to do this resulted in an unusual case of MFF leading to hospital admission. Diagnosis can be delayed if a full occupational history is not taken. Successful investigation of such cases benefits from collaborative working.

Exposure to rubber process dust and fume since 1970s in the United Kingdom; influence of origin of measurement data

The objective of this study was to compare measured concentrations of rubber process dust and rubber fume originating from different sources in the British rubber manufacturing industry. Almost 8000 exposure measurements were obtained from industry-based survey results collected by the British Rubber Manufacturers' Association (BRMA), and covering the years 1977 to 2002, and from a series of small surveys contained in the Health and Safety Executive's (HSE) National Exposure Database (HSE-NEDB) from 1980 to 2002. The analysis investigated temporal trends in the exposure concentrations and the underlying main factors responsible for these changes. Analyses were carried out using hierarchical linear mixed effects models. Average personal exposures to rubber process dust and rubber fumes were respectively a factor 2 and 4 higher for the HSE-NEDB data when compared to data originating from the industry (BRMA data). Personal exposure to rubber process dust decreased on average by 4.1% (95% CI 4.7-3.6) annually for the BRMA data and slightly less at 2.3% (95% CI 5.2-0.7%) per annum for the HSE-NEDB data. Personal exposure to rubber fume also showed a downward temporal trend of 2.9% (95% CI 3.6-2.3%) and 4.8% (95% CI 7.4-2.1%) annually for the BRMA and HSE-NEDB data, respectively. These trends differed considerably between departments. No major changes in the estimated temporal trends in exposure concentrations were observed after including the presence of local exhaust ventilation in the models for any department in the BRMA and HSE-NEDB datasets. Lack of information on the quality and status of the local exhaust ventilation is the most likely explanation for this. In conclusion, even though there were relatively similar downward time trends in both rubber process dust and fume concentrations in both datasets, the source of exposure data was an important determinant of average exposure concentrations present in the British rubber manufacturing industry. Lack of detailed auxiliary information on company size, reason for sampling, measurement strategy and other potentially important determinants of exposure prevented an explanation for the observed differences in exposure level.

Correlation between acute respiratory disease (ARE) in pregnant women and the air quality

Environmental pollution is one of the factors that contribute to exacerbate respiratory diseases (ERA) and can affect pregnancy. The records of outpatient and emergency entrances of the Hospital of Suba, were studied and tabulated, correlating the five leading causes of ERA with the monthly averages of particulated materials PM10s, fume concentration NO, N02, NOx, SO2, radiant flux (W), wind direction (DV), environmental temperature (TPM). In the evaluation, statistical measures of central tendency and the Pearson index were used. 6310 cases entering the Hospital were tabulated, corresponding 1,307 (27.9%) to pregnant women. The five leading causes of ERA presented a frequency of non specified asthma (26.1%), tonsillitis (24.4%) flu (21.8%), pharyngitis (16%) and asthma (11.5%). Variation average of the variables showed differences between the first and the second term: W (X = X 1.77vs = 1.55), DV (225.7 vs. 199.5), T°C (16.8 vs. 15.6) and PM10 (94.23 vs. 84.86); for the fumes NO (10.5 vs. 15.2), NO2 (15.9vs16.4), NOx (28.5 vs. 31.8) and SO2 (2.0 vs 3.2). The correlation showed a strong association between PM10, SO2 and non specific asthma (p < 0.007 and 0.0048) and DV and flu state (0.048) It was concluded that the environmental pollution is present in a cyclical manner during the year affecting the ERA in pregnant women, existing a significant correlation between PM10, SO2 and non specific asthma and, DV and statements flu.

Two-Zone Model Application to Breathing Zone and Area Welding Fume Concentration Data

This study assessed a professional pipefitter/welder performing shielded metal arc welding on carbon steel under field conditions. The resulting breathing zone (near field) and area (far field) welding fume concentration data were applied to the two-zone model for the purpose of determining field-derived personal exposure emission (generation) rates during actual welding work. The study is unique in that one welder was evaluated under high production conditions for 2 days at two different welding locations: a boiler room and a breezeway. Samples were collected and analyzed for total particulate following NIOSH Method 0500 and for select metals following NIOSH Method 7300. Breezeway average personal breathing zone sample total particulate concentrations ranged from 2.89 mg/m3 to 4.38 mg/m(3), Fe concentrations ranged from 0.53 to 0.63 mg/m3, and Mn concentrations ranged from 0.10 to 0.12 mg/m3. The boiler room average personal breathing zone sample total particulate concentrations ranged from 4.73 mg/m3 to 5.90 mg/m3, Fe concentrations ranged from 0.48 to 0.85 mg/m3, and Mn concentrations ranged from 0.06 to 0.16 mg/m3. Average arc times ranged from 20 to 25% of the total sampling time. Both tracer gas and anemometer techniques were used to estimate ventilation of the boiler room. The steady-state form of the two-zone model was applied to long-term and short-term sample total particulate, Fe, and Mn concentrations obtained during welding in the boiler room and breezeway. The average generation rate in the boiler room was 39.2 mg/min for TP, 6.4 mg/min for Fe, and 1.3 mg/min for Mn. The average generation rate in the breezeway was 40.0 mg/min for TP, 6.6 mg/min for Fe, and 1.2 mg/min for Mn. The field-based generation rates were considerably lower than laboratory-derived published emission rates of between 280 and 650 mg/min for TP. This study emphasizes the need for field-derived welding fume generation rates and showed the personal breathing zone and area sample concentrations can be described by the two-zone model in a way that may help the industrial hygienist estimate exposures. [Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Occupational and Environmental Hygiene for the following free supplemental resource: Tables detailing the personal breathing zone and average area sample results for breezeway welding and boiler room welding, two-zone modeling results, and boiler room welding personal breathing zone and area sample results with mixing fans on.]

Epidemiological investigation of welder's pneumoconiosis in two container manufacturing industries in Guangdong province

To investigate the incidence of welder's pneumoconiosis in container manufacturing industries in Guangdong province and present some preventive and curative strategy. Occupational epidemiology study methods were used to study the incidence of welder's pneumoconiosis in two container manufacturing enterprises (enterprise A and enterprise B). Before 2004, the rate of up-to-standard of weld fume concentration in the workplaces was relatively low (< or = 40%), and the maximum value of time weighted average (TWA) was 26.7 mg/m(3). After 2004, with the system of dust control, the rate of up-to-standard was 85% in the enterprise A. Of the 813 weld workers examined, 19 were diagnosed as welder's pneumoconiosis (stage I was 15, while I (+) was 4 ) and the incidence was 2.34% (19/813). The age of electric welders suffering from welder's pneumoconiosis and the duration of dust exposure were (33.45 + 4.64) and (8.04 + 1.97) years respectively. Chest radiographic examination showed mainly small round opacities "p". The value of MVV, FEF25%, FEF50% and FEF75% in lung function tests were significantly lower than those of the control group (P < 0.05 or P < 0.01). The main features of welder's pneumoconiosis in container manufacturing industries are the short duration of dust exposure, and small round opacities "p" in the chest radiographs. Therefore, it should be the key point of the prevention and treatment of occupational diseases in this industry to control the harmful weld fume.

Pulmonary effects of spot welding in automobile assembly

Spot welding is a type of resistance welding in which pieces of metals are pressed together and an electric current is passed through them. Spot welders are at risk of contact with some potentially hazardous agents but there are few studies about the respiratory effects of spot welding. Our objective was to study lung function and respiratory symptoms among spot welders and office workers at an automobile assembly factory in Iran. This was a cross-sectional study of 137 male spot welders and 129 office workers. We used a questionnaire to record demographic data, smoking habits, work history and respiratory symptoms. Spirometry was performed to assess lung function status. Metal fume samples from the respiratory zone of spot welders were analysed. The concentrations of metal fume were less than the American Conference of Industrial Hygienists (ACGIH) threshold limit values. There were significantly lower values for average forced expiratory volume in 1st second (FEV(1)), FEV(1)/forced vital capacity and 25-75% forced expiratory flow in spot welders compared to controls. There was also a significantly raised prevalence of respiratory symptoms (sputum and dyspnoea) in spot welders. Fifteen per cent of spot welders and 1% of controls had an obstructive pattern in spirometry. Our survey suggests that spot welders are at risk of developing respiratory symptoms and decreasing pulmonary function values despite their exposure to components of welding fume being within ACGIH guidelines.

Gravimetric and analytical evaluation of welding fume in an automobile part manufacturing factory.

Welding is one of the most exercised industrial processes which welders are exposed to chemical and physical Hazardous agents. This study was conducted to evaluate occupational and environmental exposures to aerosols generated by welding processes in a factory. A total of 28 samples of aerosols were collected at 4 different locations including indoor, outdoor, source of welding and the stacks using a high volume pump with a volumetric flow rate of 112 lit/min calibrated with a dry gas meter. The samples were collected on round 110 mm fiber glass filters, measured gravimetrically, extracted using nitric acid and analyzed with atomic absorption spectroscopy method for heavy metals including Fe, Mn, Ni, Cr3+, Cr+6, Co, and Zn. Gravimetric measuring has shown the mean values of indoor air: 1.33 mg/m3, breathing zone of the welders using coated electrodes and CO2: 7.25 mg/m3 and 6.45 mg/m3 respectively and in ventilation exhausts: 95.07 mg/m3. The mean values of Fe, Mn, and Ni were 0.8, 0.041, and 0.00 mg/m3 in indoor air, 2.7, 0.18, and 0.15 mg/m3 in breathing zone of welders used coated electrodes, and 1.75, 0.08, and 0.22 mg/m3 in breathing zone of welders used CO2 welding respectively. The concentrations of Cr3+, Cr+6, Co, and Zn were too low to be detected. The welders were exposed to high concentration of metallic fumes, which raise the risk of pulmonary dysfunction and other health disorders. Using suitable respiratory masks and Appling the effective local ventilation system may improve the working condition.

Assessment of Airborne Welding Fume Concentration for Some Manufacturing Industries in Busan

This study was conducted to describe the exposure levels of welding fumes by the type of manufacturers, work process, welding type and the size of manufacturers, and to find out the trend of chronological changes of airborne welding fume levels. The subjects of this study were 509 manufacturers, consisting of 11 types of manufacturers, 3 work processes, 7 welding types, in Busan from January, 1997 to December, 2005. Airborne concentration of welding fume was determined by manual of National Institute for Occupational Safety and Health (NIOSH), and the data were analyzed by using SPSS 10.0 for Windows program. The mean concentration of airborne welding fume in all manufacturers was <TEX>$1.29\;mg/m^3$</TEX> (Range: <TEX>$0.01{\sim}3.00\;mg/m^3)$</TEX>. The level of welding fume was the highest, as <TEX>$1.96\;mg/m^3$</TEX>, for manufactures of motor vehicles, trailers and semi-trailers, which was lower than <TEX>$5.0\;mg/m^3$</TEX> of 8 hr-TWA in Korean permissible exposure limit for welding fume. There was a significant difference in the mean levels of welding fumes by work process, showing the highest in welding workshop (<TEX>$1.39\;mg/m^3$</TEX>), followed by pipeline welding workshop (<TEX>$1.26\;mg/m^3$</TEX>) and engineering workshop (<TEX>$1.20\;mg/m^3$</TEX>). Among welding types, the mean level of welding fume was the highest in the type of <TEX>$CO_2$</TEX> & arc welding, as <TEX>$1.46\;mg/m^3$</TEX>, followed by <TEX>$CO_2$</TEX> welding (<TEX>$1.40\;mg/m^3$</TEX>), shielded metal arc welding (<TEX>$1.31\;mg/m^3$</TEX>), spot welding (<TEX>$1.27\;mg/m^3$</TEX>), and so on. The highest mean level of welding fume was <TEX>$1.58\;mg/m^3$</TEX> in work process of pipe line welding workshop for the manufacturers of basic iron and steel, and <TEX>$2.27\;mg/m^3$</TEX> in the type of arc welding for the manufactures building ship and boats. By the size of manufacturers, the mean concentration of welding fume for manufactures in small scale with less than 50 workers was the highest as <TEX>$1.45\;mg/m^3$</TEX> (Range: <TEX>$0.07{\sim}3.00\;mg/m^3)$</TEX>. The mean level of welding fume was the highest as <TEX>$1.39\;mg/m^3$</TEX> both in 1997 and in 2005, showing a trend of fluctuating periodically within a range of <TEX>$1.10{\sim}1.39\;mg/m^3$</TEX>. The above results suggested that more effective control program for work environment producing welding fumes should be developed and applied since there were significant variations in welding fume levels by the type of manufacturers, work processes, welding types, the size of manufactures, and by year.