Annals of Occupational Hygiene (Ann Occup Hyg)

Publications in this journal

• Article: Comparison of Established Systems for Measuring the Dustiness of Powders with the UNC Dustiness Tester Developed Especially for Pharmaceutical Substances.

  Sylvia Bach, Udo Eickmann, Eberhard Schmidt
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  ABSTRACT: Four methods for evaluating the dustiness of powders have been compared. The relatively new UNC Dustiness Tester first described by Boundy et al. (2006) in the Annals of Occupational Hygiene, which was developed specifically for the measurement of hazardous and/or highly potent substances, a single-drop device, a rotating-drum method, and a continuous drop-down apparatus. The four methods show four different ratings of dustiness for nine reference materials. This article describes the differences, explores reasons for the deviations, identifies a need for distinct dustiness test methods, and highlights the significance for occupational health and safety.
  Annals of Occupational Hygiene 06/2013;
• Article: Exposure of Highway Maintenance Workers to Fine Particulate Matter and Noise.

  Reto Meier, Wayne E Cascio, Brigitta Danuser, Michael Riediker
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  ABSTRACT: In this study, we assessed the mixed exposure of highway maintenance workers to airborne particles, noise, and gaseous co-pollutants. The aim was to provide a better understanding of the workers' exposure to facilitate the evaluation of short-term effects on cardiovascular health endpoints. To quantify the workers' exposure, we monitored 18 subjects during 50 non-consecutive work shifts. Exposure assessment was based on personal and work site measurements and included fine particulate matter (PM2.5), particle number concentration (PNC), noise (Leq), and the gaseous co-pollutants: carbon monoxide, nitrogen dioxide, and ozone. Mean work shift PM2.5 concentrations (gravimetric measurements) ranged from 20.3 to 321 μg m(-3) (mean 62 μg m(-3)) and PNC were between 1.6×10(4) and 4.1×10(5) particles cm(-3) (8.9×10(4) particles cm(-3)). Noise levels were generally high with Leq over work shifts from 73.3 to 96.0 dB(A); the averaged Leq over all work shifts was 87.2 dB(A). The highest exposure to fine and ultrafine particles was measured during grass mowing and lumbering when motorized brush cutters and chain saws were used. Highest noise levels, caused by pneumatic hammers, were measured during paving and guardrail repair. We found moderate Spearman correlations between PNC and PM2.5 (r = 0.56); PNC, PM2.5, and CO (r = 0.60 and r = 0.50) as well as PNC and noise (r = 0.50). Variability and correlation of parameters were influenced by work activities that included equipment causing combined air pollutant and noise emissions (e.g. brush cutters and chain saws). We conclude that highway maintenance workers are frequently exposed to elevated airborne particle and noise levels compared with the average population. This elevated exposure is a consequence of the permanent proximity to highway traffic with additional peak exposures caused by emissions of the work-related equipment.
  Annals of Occupational Hygiene 05/2013;
• Article: Determinants Explaining the Variability of Hand-Transmitted Vibration Emissions From Two Different Work Tasks: Grinding and Cutting Using Angle Grinders.

  Liljelind Ingrid, Hans Pettersson, Leif Nilsson, Jens Wahlström, Allan Toomingas, Ronnie Lundström, Lage Burström
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  ABSTRACT: Background:There are numerous factors including physical, biomechanical, and individual that influence exposure to hand-transmitted vibration (HTV) and cause variability in the exposure measurements. Knowledge of exposure variability and determinants of exposure could be used to improve working conditions. We performed a quasi-experimental study, where operators performed routine work tasks in order to obtain estimates of the variance components and to evaluate the effect of determinants, such as machine-wheel combinations and individual operator characteristics. METHODS: Two pre-defined simulated work tasks were performed by 11 operators: removal of a weld puddle of mild steel and cutting of a square steel pipe. In both tasks, four angle grinders were used, two running on compressed air and two electrically driven. Two brands of both grinding and cutting wheels were used. Each operator performed both tasks twice in a random order with each grinder and wheel and the time to complete each task was recorded. Vibration emission values were collected and the wheel wear was measured as loss of weight. Operators' characteristics collected were as follows: age, body height and weight, length and volume of their hands, maximum hand grip force, and length of work experience with grinding machines (years). The tasks were also performed by one operator who used four machines of the same brand. Mixed and random effects models were used in the statistical evaluation. RESULTS: The statistical evaluation was performed for grinding and cutting separately and we used a measure referring to the sum of the 1-s r.m.s. average frequency-weighted acceleration over time for completing the work task (a sa). Within each work task, there was a significant effect as a result of the determinants 'the machine used', 'wheel wear', and 'time taken to complete the task'. For cutting, 'the brand of wheel' used also had a significant effect. More than 90% of the inherent variability in the data was explained by the determinants. The two electrically powered machines had a mean a sa that was 2.6 times higher than the two air-driven machines. For cutting, the effect of the brand of wheel on a sa was ~0.1 times. The a sa increased both with increasing wheel wear and with time taken to complete the work task. However, there were also a number of interaction effects which, to a minor extent, modified the a sa. Only a minor part (1%) of the total variability was attributed to the operator: for cutting, the volume of the hands, maximum grip force, and body weight were significant, while for grinding, it was the maximum grip force. There was no clear difference in a sa between the four copies of the same brand of each machine. CONCLUSIONS: By including determinants that were attributed to the brand of both machine and wheel used as well as the time taken to complete the work task, we were able to explain >90% of the variability. The dominating determinant was the brand of the machine. Little variability was found between operators, indicating that the overall effect as due to the operator was small.
  Annals of Occupational Hygiene 05/2013;
• Article: Direct-Reading Inhalable Dust Monitoring--An Assessment of Current Measurement Methods.

  Andrew Thorpe, Peter T Walsh
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  ABSTRACT: Direct-reading dust monitors designed specifically to measure the inhalable fraction of airborne dust are not widely available. Current practice therefore often involves comparing the response of photometer-type dust monitors with the concentration measured with a reference gravimetric inhalable sampler, which is used to adjust the dust monitor measurement. However, changes in airborne particle size can result in significant errors in the estimation of inhalable concentration by this method. The main aim of this study was to assess how these dust monitors behave when challenged with airborne dust containing particles in the inhalable size range and also to investigate alternative dust monitors whose response might not be as prone to variations in particle size or that could be adapted to measure inhalable dust concentration. Several photometer-type dust monitors and a Respicon TM, tapered element oscillating microbalance (TEOM) personal dust monitor (PDM) 3600, TEOM 1400, and Dustrak DRX were assessed for the measurement of airborne inhalable dust during laboratory and field trials. The PDM was modified to allow it to sample and measure larger particles in the inhalable size range. During the laboratory tests, the dust monitors and reference gravimetric samplers were challenged inside a large dust tunnel with aerosols of industrial dusts known to present an inhalable hazard and aluminium oxide powders with a range of discrete particle sizes. A constant concentration of each dust type was generated and peak concentrations of larger particles were periodically introduced to investigate the effects of sudden changes in particle size on monitor calibration. The PDM, Respicon, and DataRam photometer were also assessed during field trials at a bakery, joinery, and a grain mill. Laboratory results showed that the Respicon, modified PDM, and TEOM 1400 observed good linearity for all types of dust when compared with measurements made with a reference IOM sampler; the photometer-type dust monitors on the other hand showed little correlation. The Respicon also accurately measured the inhalable concentration, whereas the modified PDM underestimated it by ~27%. Photometer responses varied considerably with changing particle size, which resulted in appreciable errors in airborne inhalable dust concentration measurements. Similar trends were also observed during field trials. Despite having limitations, both the modified PDM and Respicon showed promise as real-time inhalable dust monitors.
  Annals of Occupational Hygiene 05/2013;
• Article: Exposure to Parvalbumin Allergen and Aerosols among Herring Processing Workers.

  Anna Dahlman-Höglund, Anne Renström, Fernando Acevedo, Eva Andersson
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  ABSTRACT: Background:There are increasing reports of allergies and respiratory symptoms among workers in the fish processing industry, coinciding with an increasing use of high-pressure water in the processing plants. However, few studies have measured exposure in these work environments. OBJECTIVES: The aim of this study was to characterize the occupational exposure of workers to herring antigen and to screen environmental factors at a herring (Clupea harengus) plant in which new and more encapsulated filleting machines had been installed. To assist in this, a method to assess airborne exposure to herring allergen was needed. METHODS: Exposure to airborne herring antigen, mould spores, and endotoxin were measured during work. Antigen exposure was assessed using a newly developed sensitive (detection limit, 0.1 ng ml(-1)) rabbit polyclonal sandwich enzyme-linked immunosorbent assay against the major herring muscle protein allergen, parvalbumin. Aerosols were measured by mass concentration (DataRAM) and number of particles (Climet I-500). RESULTS: Personal geometric mean herring allergen exposure was 986 ng m(-3) at the old filleting workstations and 725 ng m(-3) at the new workstations (difference not significant). Outside the production room, the level was ~130 ng m(-3). Number of particles and mass concentration were both significantly lower around the new machines than around the old machines (P < 0.001 and P < 0.0001, respectively). The highest particle count was seen for the 0.3-0.5 μm fraction, with more than 400 000 particles per cubic metre air. Endotoxin concentration in the air varied between 3 and 92 EU m(-3), with the highest levels when the catch mainly contained herring that had eaten krill or seaweed. CONCLUSIONS: We developed a sensitive method to detect herring antigen. High exposure to herring antigen was measured during filleting work. The particles in the air around the fillet machines were mainly <0.5 μm and the newer encapsulated machines generated fewer particles. It is important to reduce occupational exposure of workers to aerosols by improving the ventilation system, machines, and organization of work.
  Annals of Occupational Hygiene 05/2013;
• Article: Toluene Diisocyanate Emission to Air and Migration to a Surface from a Flexible Polyurethane Foam.

  Erik Vangronsveld, Steven Berckmans, Mark Spence
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  ABSTRACT: Flexible polyurethane foam (FPF) is produced from the reaction of toluene diisocyanate (TDI) and polyols. Because of the potential for respiratory sensitization following exposure to TDI, concerns have been raised about potential consumer exposure to TDI from residual 'free TDI' in FPF products. Limited and conflicting results exist in the literature concerning the presence of unreacted TDI remaining in FPF as determined by various solvent extraction and analysis techniques. Because residual TDI results are most often intended for application in assessment of potential human exposure to TDI from FPF products, testing techniques that more accurately simulated human contact with foam were designed. To represent inhalation exposure to TDI from polyurethane foam, a test that measured the emission of TDI to air was conducted. For simulation of human dermal exposure to TDI from polyurethane foam, a migration test technique was designed. Emission of TDI to air was determined for a representative FPF using three different emission test cells. Two were commercially available cells that employ air flow over the surface of the foam [the Field and Laboratory Emission Cell (FLEC®) and the Micro-Chamber/Thermal Extraction™ cell]. The third emission test cell was of a custom design and features air flow through the foam sample rather than over the foam surface. Emitted TDI in the air of the test cells was trapped using glass fiber filters coated with 1-(2-methoxyphenyl)-piperazine (MP), a commonly used derivatizing agent for diisocyanates. The filters were subsequently desorbed and analyzed by liquid chromatography/mass spectrometry. Measurement of TDI migration from representative foam was accomplished by placing glass fiber filters coated with MP on the outer surfaces of a foam disk and then compressing the filters against the disk using a clamping apparatus for periods of 8 and 24 h. The sample filters were subsequently desorbed and analyzed in the same manner as for the emission tests. Although the foam tested had detectable levels of solvent-extractable TDI (56ng TDI g(-1) foam for the foam used in emissions tests; 240-2800ng TDI g(-1) foam for the foam used in migration tests), no TDI was detected in any of the emission or migration tests. Method detection limits (MDLs) for the emissions tests ranged from 0.03 to 0.5ng TDI g(-1) foam (0.002-0.04ng TDI cm(-2) of foam surface), whereas those for the migration tests were 0.73ng TDI g(-1) foam (0.16ng TDI cm(-2) of foam surface). Of the three emission test methods used, the FLEC® had the lowest relative MDLs (by a factor of 3-10) by virtue of its high chamber loading factor. In addition, the FLEC® cell offers well-established conformity with emission testing standard methods.
  Annals of Occupational Hygiene 05/2013;
• Article: Isocyanate Exposure Assessment Combining Industrial Hygiene Methods with Biomonitoring for End Users of Orthopedic Casting Products.

  Ronald L Pearson, Perry W Logan, Anita M Kore, Constance M Strom, Lisa M Brosseau, Richard L Kingston
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  ABSTRACT: Previous studies have suggested a potential risk to healthcare workers applying isocyanate-containing casts, but the authors reached their conclusions based on immunological or clinical pulmonology test results alone. We designed a study to assess potential exposure to methylene diphenyl diisocyanate (MDI) among medical personnel applying orthopedic casts using two different application methods. Air, dermal, surface, and glove permeation sampling methods were combined with urinary biomonitoring to assess the overall risk of occupational asthma to workers handling these materials. No MDI was detected in any of the personal and area air samples obtained. No glove permeation of MDI was detected. A small proportion of surface (3/45) and dermal wipe (1/60) samples were positive for MDI, but were all from inexperienced technicians. Urinary metabolites of MDI [methylenedianiline (MDA)] were detected in three of six study participants prior to both a 'dry' and 'wet' application method, five of six after the dry method, and three of six after the wet method. All MDA results were below levels noted in worker or general populations. Our conclusion is that the risk of MDI exposure is small, but unquantifiable. Because there is some potential risk of dermal exposure, medical personnel are instructed to wear a minimum of 5-mil-thick (5 mil = 0.005 inches) nitrile gloves and avoid contact to unprotected skin. This could include gauntlets, long sleeves, and/or a laboratory coat.
  Annals of Occupational Hygiene 05/2013;
• Article: A Pragmatic approach to standard setting : the example of coal tar products and asphalt

  J.P. Chong, A T Haines, Dave K. Verma
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  ABSTRACT: Sumario: This article will outline a pragmatic approach directed to incorporating key elements of a scientific review of the literature and derive a proposal for an occupational exposure standard for coal tar, coal tar pitch, creosote, petroleum pitch, bitumen and asphalt, six substances which contain polynuclear aromatic hydrocarbons. Five approaches to the standard setting process are reviewed and their strengths and weaknesses discussed
  Annals of Occupational Hygiene 04/2013; 33:197-208.
• Article: Evaporation of Volatile Organic Compounds from Human Skin In Vitro.

  Rachna M Gajjar, Matthew A Miller, Gerald B Kasting
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  ABSTRACT: The specific evaporation rates of 21 volatile organic compounds (VOCs) from either human skin or a glass substrate mounted in modified Franz diffusion cells were determined gravimetrically. The diffusion cells were positioned either on a laboratory bench top or in a controlled position in a fume hood, simulating indoor and outdoor environments, respectively. A data set of 54 observations (34 skin and 20 glass) was assembled and subjected to a correlation analysis employing 5 evaporative mass transfer relationships drawn from the literature. Models developed by Nielsen et al. (Prediction of isothermal evaporation rates of pure volatile organic compounds in occupational environments: a theoretical approach based on laminar boundary layer theory. Ann Occup Hyg 1995;39:497-511.) and the U.S. Environmental Protection Agency (Peress, Estimate evaporative losses from spills. Chem Eng Prog 2003; April: 32-34.) were found to be the most effective at correlating observed and calculated evaporation rates under the various conditions. The U.S. EPA model was selected for further use based on its simplicity. This is a turbulent flow model based only on vapor pressure and molecular weight of the VOC and the effective air flow rate u. Optimum values of u for the two laboratory environments studied were 0.23 m s(-1) (bench top) and 0.92 m s(-1) (fume hood).
  Annals of Occupational Hygiene 04/2013;
• Article: The Future of Exposure Assessment: Perspectives From the X2012 Conference.

  Frank De Vocht, Christine Northage, Chris Money, John W Cherrie, Bob Rajan-Sithamparanadarajah, Peter Egeghy, Karen Niven, Paul Demers, Martie Van Tongeren
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  ABSTRACT: The British Occupational Hygiene Society, in collaboration with the Institute of Occupational Medicine, the University of Manchester, the UK Health and Safety Executive, and the University of Aberdeen hosted the 7th International Conference on the Science of Exposure Assessment (X2012) on 2 July-5 July 2012 in Edinburgh, UK. The conference ended with a special session at which invited speakers from government, industry, independent research institutes, and academia were asked to reflect on the conference and discuss what may now constitute the important highlights or drivers of future exposure assessment research. This article summarizes these discussions with respect to current and future technical and methodological developments. For the exposure science community to continue to have an impact in protecting public health, additional efforts need to be made to improve partnerships and cross-disciplinary collaborations, although it is equally important to ensure that the traditional occupational exposure themes are still covered as these issues are becoming increasingly important in the developing world. To facilitate this the 'X' conferences should continue to retain a holistic approach to occupational and non-occupational exposures and should actively pursue collaborations with other disciplines and professional organizations to increase the presence of consumer and environmental exposure scientists.
  Annals of Occupational Hygiene 04/2013; 57(3):280-285.
• Article: Annals of Occupational Hygiene Performance, 2012.

  Noah S Seixas
  Annals of Occupational Hygiene 04/2013; 57(3):279.
• Article: Burnout Among Occupational Physicians: A Threat to Occupational Health Systems?--A Nationwide Cross-sectional Survey.

  François-Xavier Lesage, Sophie Berjot, Emin Altintas, Benjamin Paty
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  ABSTRACT: OBJECTIVES: Burnout among occupational health physicians in France was measured in a nationwide cross-sectional survey. The relationships between each dimension of burnout (emotional exhaustion, depersonalization, and feelings of low personal accomplishment) and stress level, identity threat, and job characteristics were analysed. METHODS: E-mails were sent out to all occupational physicians working in France by the French Ministry of Labour, inviting them to fill out an online questionnaire. This questionnaire included the Maslach Burnout Inventory, the Perceived Stress Scale, and the Primary Appraisal of Identity scale. Job characteristics were measured with survey-specific questions. RESULTS: Of the 5010 occupational physicians who were potentially contacted, 1670 (33%) completed the online questionnaire. The estimated prevalence of burnout was 11.8%, twice as high as in a sample of French general practitioners (5%). The main characteristic of the burnout pattern was feelings of very low personal accomplishment (63.9%). Job characteristics were only weakly correlated with burnout, but stress level and identity threat were correlated with all three dimensions of burnout. The perceived stress was the main risk factor for emotional exhaustion and identity threat for feelings of low personal accomplishment. CONCLUSIONS: The health status of occupational physicians is important for both the individual physicians and for the occupational health system. Occupational physicians are unwell, and we probably need to change the way we currently cope with burnout. This is not only a stress-induced syndrome, resulting from high workloads, but a low self-esteem-induced syndrome, too.
  Annals of Occupational Hygiene 03/2013;
• Article: Flow and Containment Characteristics of a Sash-less, Variable-Height Inclined Air-Curtain Fume Hood.

  Rong Fung Huang, Jia-Kun Chen, Wei-Lun Hung
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  ABSTRACT: To increase containment efficiency and reduce energy consumption, a sash-less, variable-height inclined air-curtain fume hood (sIAC hood) was developed and tested by a laser-assisted flow visualization technique and tracer-gas detection method. This novel design requires neither sash nor baffle. The sIAC hood employed the inclined push-pull air-curtain technique and two deflection plates installed on the side walls of the hood to induce a tetra-vortex flow structure. The results of flow visualization showed that the slot for suction flow, offset from the slot for the up-blowing jet, caused the air curtain to incline towards the rear wall, thus enhancing the robustness of the tetra-vortex flow structure. Such a flow structure could reduce the influence of draught and human walk-by across the hood face. The containment around the central area of the hood was isolated by the inclined push-pull air curtain. The pollutants carried by the reverse flow induced by the flow separation were guided by the deflection plates from the side walls towards the rear, thus contributing to the formation of the tetra-vortex flow structure. The up/down movable ceiling positioned the suction slot close to the device's pollutant emission opening, but left room (less than 50cm) for unrestricted hand movement. Testing was carried out based on the methodology described in EN14175. The results of a static test showed that small face velocities of 0.25 and 0.16 m s(-1) were enough to obtain nearly null leakage levels for low and tall pollutant sources. The results of a traversing plate test showed that the face velocity, 0.32 m s(-1), would cause negligibly small leakage levels. The sIAC hood could obtain significantly higher containment efficiency than a conventional hood by operating at a face velocity significantly lower than that of conventional hoods.
  Annals of Occupational Hygiene 03/2013;
• Article: Comparison of Solvent/Derivatization Agent Systems for Determination of Extractable Toluene Diisocyanate from Flexible Polyurethane Foam.

  Erik Vangronsveld, Steven Berckmans, Mark Spence
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  ABSTRACT: Flexible polyurethane foam (FPF) is produced from the reaction of toluene diisocyanate (TDI) and polyols. Limited and conflicting results exist in the literature concerning the presence of unreacted TDI remaining in FPF as determined by various solvent extraction and analysis techniques. This study reports investigations into the effect of several solvent/derivatization agent combinations on extractable TDI results and suggests a preferred method. The suggested preferred method employs a syringe-based multiple extraction of foam samples with a toluene solution of 1-(2-methoxyphenyl)-piperazine. Extracts are analyzed by liquid chromatography using an ion trap mass spectrometry detection technique. Detection limits of the method are ~10ng TDI g(-1) foam (10 ppb, w/w) for each TDI isomer (i.e. 2,4-TDI and 2,6-TDI). The method was evaluated by a three-laboratory interlaboratory comparison using two representative foam samples. The total extractable TDI results found by the three labs for the two foams were in good agreement (relative standard deviation of the mean of 30-40%). The method has utility as a basis for comparing FPFs, but the interpretation of extractable TDI results using any solvent as the true value for 'free' or 'unreacted' TDI in the foam is problematic, as demonstrated by the difference in the extracted TDI results from the different extraction systems studied. Further, a consideration of polyurethane foam chemistry raises the possibility that extractable TDI may result from decomposition of parts of the foam structure (e.g. dimers, biurets, and allophanates) by the extraction system.
  Annals of Occupational Hygiene 03/2013;
• Article: Personal, Professional, and Work Factors Associated With Australian Clinical Medical Practitioners' Experiences of Workplace Aggression.

  Danny J Hills, Catherine M Joyce
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  ABSTRACT: OBJECTIVES: This study examined the extent to which a range of personal, professional, and work factors are associated with workplace aggression experienced by medical practitioners in Australian clinical practice settings. METHODS: An exploratory, descriptive study of cross-sectional, self-report survey design was undertaken in the third wave of the Medicine in Australia: Balancing Employment and Life survey during 2010-2011. Of 16&emsp14;327 medical practitioners sampled, 9951 (60.9%) responded and 9449 (57.9%) worked in clinical practice. Logistic regression was undertaken to detect statistically significant associations between a suite of personal, professional, and work variables and eight binary outcome variables measuring exposure to verbal or written and physical aggression from patients, patients' relatives or carers, co-workers and others external to the workplace during the previous year. RESULTS: Age was consistently negatively associated and external control orientation was consistently positively associated with workplace aggression exposure from each source. Key variables related to work conditions (total hours worked, unpredictable work hours, a poor support network of other doctors, patients with unrealistic expectations, patients with complex health and social problems) and the presence of workplace aggression prevention and minimization strategies (alerts to high risk of aggression, restricting or withdrawing access for aggressive persons and optimized patient waiting) were also associated with aggression exposure. CONCLUSIONS: A broader implementation of strategies to prevent and minimize the likelihood and consequences of workplace aggression is required and needs to take account of both the individual and sub-group profiles of medical practitioners. Strategies need to mitigate the more challenging aspects of medical work, including excessive work hours, inadequate access to professional support networks, and larger caseloads of patients with complex conditions.
  Annals of Occupational Hygiene 03/2013;
• Article: Functionality Based Detection of Airborne Engineered Nanoparticles in Quasi Real Time: A New Type of Detector and a New Metric.

  Nicole Neubauer, Martin Seipenbusch, Gerhard Kasper
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  ABSTRACT: A new type of detector which we call the Catalytic Activity Aerosol Monitor (CAAM) was investigated towards its capability to detect traces of commonly used industrial catalysts in ambient air in quasi real time. Its metric is defined as the catalytic activity concentration (CAC) expressed per volume of sampled workplace air. We thus propose a new metric which expresses the presence of nanoparticles in terms of their functionality - in this case a functionality of potential relevance for damaging effects - rather than their number, surface, or mass concentration in workplace air. The CAAM samples a few micrograms of known or anticipated airborne catalyst material onto a filter first and then initiates a chemical reaction which is specific to that catalyst. The concentration of specific gases is recorded using an IR sensor, thereby giving the desired catalytic activity. Due to a miniaturization effort, the laboratory prototype is compact and portable. Sensitivity and linearity of the CAAM response were investigated with catalytically active palladium and nickel nano-aerosols of known mass concentration and precisely adjustable primary particle size in the range of 3-30nm. With the miniature IR sensor, the smallest detectable particle mass was found to be in the range of a few micrograms, giving estimated sampling times on the order of minutes for workplace aerosol concentrations typically reported in the literature. Tests were also performed in the presence of inert background aerosols of SiO2, TiO2, and Al2O3. It was found that the active material is detectable via its catalytic activity even when the particles are attached to a non-active background aerosol.
  Annals of Occupational Hygiene 03/2013;
• Article: Effect of Flow Characteristics on Ultrafine Particle Emissions from Range Hoods.

  Li-Ching Tseng, Chih-Chieh Chen
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  ABSTRACT: In order to understand the physical mechanisms of the production of nanometer-sized particulate generated from cooking oils, the ventilation of kitchen hoods was studied by determining the particle concentration, particle size distribution, particle dimensions, and hood's flow characteristics under several cooking scenarios. This research varied the temperature of the frying operation on one cooking operation, with three kinds of commercial cooking oils including soybean oil, olive oil, and sunflower oil. The variations of particle concentration and size distributions with the elevated cooking oil temperatures were presented. The particle concentration increases as a function of temperature. For oil temperatures ranging between 180°C and 210°C, a 5°C increase in temperature increased the number concentration of ultrafine particles by 20-50%. The maximum concentration of ultrafine particles was found to be approximately 6×106 particles per cm3 at 260°C. Flow visualization techniques and particle distribution measurement were performed for two types of hood designs, a wall-mounted range hood and an island hood, at a suction flow rate of 15 m3 min-1. The flow visualization results showed that different configurations of kitchen hoods induce different aerodynamic characteristics. By comparing the results of flow visualizations and nanoparticle measurements, it was found that the areas with large-scale turbulent vortices are more prone to dispersion of ultrafine particle leakage because of the complex interaction between the shear layers and the suction movement that results from turbulent dispersion. We conclude that the evolution of ultrafine particle concentration fluctuations is strongly affected by the location of the hood, which can alter the aerodynamic features. We suggest that there is a correlation between flow characteristics and amount of contaminant leakage. This provides a comprehensive strategy to evaluate the effectiveness of kitchen hoods in capturing cooking oil fumes, which is based on an assessment of the entire hood face exposure instead of on breathing-zone sampling alone.
  Annals of Occupational Hygiene 03/2013;
• Article: The Symmetric-Range Accuracy under a One-Way Random Model with Balanced or Unbalanced Data.

  Kalimuthu Krishnamoorthy, Thomas Mathew
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  ABSTRACT: The symmetric-range accuracy of a sampler is defined as the fractional range, symmetric about the true concentration, that includes a specified proportion of sampler measurements. In this article, we give an explicit expression for assuming that the sampler measurements follow a one-way random model so as to capture different components of variability, for example, variabilities among and within different laboratories or variabilities among and within exposed workers. We derive an upper confidence limit for based on the concept of a 'generalized confidence interval'. A convenient approximation is also provided for computing the upper confidence limit. Both balanced and unbalanced data situations are investigated. Monte Carlo evaluation indicates that the proposed upper confidence limit is satisfactory even for small samples. The statistical procedures are illustrated using an example.
  Annals of Occupational Hygiene 03/2013;
• Article: EXPOSURE TO CHLORAMINES IN THE ATMOSPHERE OF INDOOR SWIMMING POOLS

  M.Hery, G. Hecht, J.M. Gerber, J.C. Gendre, G. Hubert, J. Rebuffaud
  Annals of Occupational Hygiene 02/2013; 39(4):427-439.
• Article: A Job-Exposure Matrix for Occupational Noise: Development and Validation.

  Mattias Sjöström, Marie Lewné, Magnus Alderling, Pernilla Willix, Peter Berg, Per Gustavsson, Magnus Svartengren
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  ABSTRACT: OBJECTIVE: To develop a job-exposure matrix (JEM) for occupational noise in Sweden and to estimate its validity. METHODS: The JEM, developed by a group of experienced occupational hygienists, contains 321 job families with information regarding occupational noise from 1970 to 2004. The occupational noise information derives from measurements collected from different sources. The time period label has a 5-year scale starting in 1970. The estimated average 8h (TWA) noise level in decibel [dB(A)] for every 5-year period was coded either as <75 dB(A), 75-84 dB(A), or ≥85 dB(A) and the risk of peak level exposure assessed. The validity of the JEM is tested, using Svensson's non-parametric methods based on classification consensus, reached by a second group of occupational hygienists.Results/Discussion:Validation results show ~ 80% agreement and no systematic differences, in classification, between the two different groups of occupational hygienists, classifying the occupational noise exposure. However, classification of peak level exposure did show a systematic difference in relative position. The results will give more power to the JEM that it gives a good general estimate for the occupational noise levels in Sweden for different job families during 1970-2004. We, thus, intend to use it in further studies and also make it available to collaborators.
  Annals of Occupational Hygiene 02/2013;