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1.  Workplace measurements by the U.S. Occupational Safety and Health Administration since 1979: Descriptive analysis and potential uses for exposure assessment 
Annals of Occupational Hygiene  2013;57(5):681-683.
This letter summarizes modifications to the results presented in Lavoué et al. (2012): Lavoué, J., Burstyn, I., Friesen, M. (2012) Workplace Measurements by the US Occupational Safety and Health Administration since 1979: Descriptive Analysis and Potential Uses for Exposure Assessment. Annals of occupational hygiene 57(1):77–97. Although several results were altered, the conclusions were not affected by the changes.
PMCID: PMC3900859  PMID: 23946941
2.  Assessing Occupational Exposure to Chemicals in an International Epidemiological Study of Brain Tumours 
Annals of Occupational Hygiene  2013;57(5):610-626.
The INTEROCC project is a multi-centre case–control study investigating the risk of developing brain cancer due to occupational chemical and electromagnetic field exposures. To estimate chemical exposures, the Finnish Job Exposure Matrix (FINJEM) was modified to improve its performance in the INTEROCC study and to address some of its limitations, resulting in the development of the INTEROCC JEM. An international team of occupational hygienists developed a crosswalk between the Finnish occupational codes used in FINJEM and the International Standard Classification of Occupations 1968 (ISCO68). For ISCO68 codes linked to multiple Finnish codes, weighted means of the exposure estimates were calculated. Similarly, multiple ISCO68 codes linked to a single Finnish code with evidence of heterogeneous exposure were refined. One of the key time periods in FINJEM (1960–1984) was split into two periods (1960–1974 and 1975–1984). Benzene exposure estimates in early periods were modified upwards. The internal consistency of hydrocarbon exposures and exposures to engine exhaust fumes was improved. Finally, exposure to polycyclic aromatic hydrocarbon and benzo(a)pyrene was modified to include the contribution from second-hand smoke. The crosswalk ensured that the FINJEM exposure estimates could be applied to the INTEROCC study subjects. The modifications generally resulted in an increased prevalence of exposure to chemical agents. This increased prevalence of exposure was not restricted to the lowest categories of cumulative exposure, but was seen across all levels for some agents. Although this work has produced a JEM with important improvements compared to FINJEM, further improvements are possible with the expansion of agents and additional external data.
PMCID: PMC3888250  PMID: 23467593
cancer epidemiology; case–control; job-exposure matrix
3.  Influence of Analysis Methods on Interpretation of Hazard Maps 
Annals of Occupational Hygiene  2012;57(5):558-570.
Exposure or hazard mapping is becoming increasingly popular among industrial hygienists. Direct-reading instruments used for hazard mapping of data collection are steadily increasing in reliability and portability while decreasing in cost. Exposure measurements made with these instruments generally require no laboratory analysis although hazard mapping can be a time-consuming process. To inform decision making by industrial hygienists and management, it is crucial that the maps generated from mapping data are as accurate and representative as possible. Currently, it is unclear how many sampling locations are necessary to produce a representative hazard map. As such, researchers typically collect as many points as can be sampled in several hours and interpolation methods are used to produce higher resolution maps. We have reanalyzed hazard-mapping data sets from three industrial settings to determine which interpolation methods yield the most accurate results. The goal is to provide practicing industrial hygienists with some practical guidelines to generate accurate hazard maps with ‘off-the-shelf’ mapping software. Visually verifying the fit of the variogram model is crucial for accurate interpolation. Exponential and spherical variogram models performed better than Gaussian models. It was also necessary to diverge from some of the default interpolation parameters such as the number of bins used for the experimental variogram and whether or not to allow for a nugget effect to achieve reasonable accuracy of the interpolation for some data sets.
PMCID: PMC3916742  PMID: 23258453
exposure mapping; hazard mapping; interpolation; kriging
4.  Comparison of Algorithm-based Estimates of Occupational Diesel Exhaust Exposure to Those of Multiple Independent Raters in a Population-based Case–Control Study 
Annals of Occupational Hygiene  2012;57(4):470-481.
Algorithm-based exposure assessments based on patterns in questionnaire responses and professional judgment can readily apply transparent exposure decision rules to thousands of jobs quickly. However, we need to better understand how algorithms compare to a one-by-one job review by an exposure assessor. We compared algorithm-based estimates of diesel exhaust exposure to those of three independent raters within the New England Bladder Cancer Study, a population-based case–control study, and identified conditions under which disparities occurred in the assessments of the algorithm and the raters.
Occupational diesel exhaust exposure was assessed previously using an algorithm and a single rater for all 14 983 jobs reported by 2631 study participants during personal interviews conducted from 2001 to 2004. Two additional raters independently assessed a random subset of 324 jobs that were selected based on strata defined by the cross-tabulations of the algorithm and the first rater’s probability assessments for each job, oversampling their disagreements. The algorithm and each rater assessed the probability, intensity and frequency of occupational diesel exhaust exposure, as well as a confidence rating for each metric. Agreement among the raters, their aggregate rating (average of the three raters’ ratings) and the algorithm were evaluated using proportion of agreement, kappa and weighted kappa (κw). Agreement analyses on the subset used inverse probability weighting to extrapolate the subset to estimate agreement for all jobs. Classification and Regression Tree (CART) models were used to identify patterns in questionnaire responses that predicted disparities in exposure status (i.e., unexposed versus exposed) between the first rater and the algorithm-based estimates.
For the probability, intensity and frequency exposure metrics, moderate to moderately high agreement was observed among raters (κw = 0.50–0.76) and between the algorithm and the individual raters (κw = 0.58–0.81). For these metrics, the algorithm estimates had consistently higher agreement with the aggregate rating (κw = 0.82) than with the individual raters. For all metrics, the agreement between the algorithm and the aggregate ratings was highest for the unexposed category (90–93%) and was poor to moderate for the exposed categories (9–64%). Lower agreement was observed for jobs with a start year <1965 versus ≥1965. For the confidence metrics, the agreement was poor to moderate among raters (κw = 0.17–0.45) and between the algorithm and the individual raters (κw = 0.24–0.61). CART models identified patterns in the questionnaire responses that predicted a fair-to-moderate (33–89%) proportion of the disagreements between the raters’ and the algorithm estimates.
The agreement between any two raters was similar to the agreement between an algorithm-based approach and individual raters, providing additional support for using the more efficient and transparent algorithm-based approach. CART models identified some patterns in disagreements between the first rater and the algorithm. Given the absence of a gold standard for estimating exposure, these patterns can be reviewed by a team of exposure assessors to determine whether the algorithm should be revised for future studies.
PMCID: PMC3629988  PMID: 23184256
case–control; diesel exhaust; expert judgement; exposure assessment
5.  Uncertainty in Aspiration Efficiency Estimates from Torso Simplifications in Computational Fluid Dynamics Simulations 
Annals of Occupational Hygiene  2012;57(2):184-199.
Computational fluid dynamics (CFD) has been used to report particle inhalability in low velocity freestreams, where realistic faces but simplified, truncated, and cylindrical human torsos were used. When compared to wind tunnel velocity studies, the truncated models were found to underestimate the air’s upward velocity near the humans, raising questions about aspiration estimation. This work compares aspiration efficiencies for particles ranging from 7 to 116 µm using three torso geometries: (i) a simplified truncated cylinder, (ii) a non-truncated cylinder, and (iii) an anthropometrically realistic humanoid body. The primary aim of this work is to (i) quantify the errors introduced by using a simplified geometry and (ii) determine the required level of detail to adequately represent a human form in CFD studies of aspiration efficiency. Fluid simulations used the standard k-epsilon turbulence models, with freestream velocities at 0.1, 0.2, and 0.4 m s−1 and breathing velocities at 1.81 and 12.11 m s−1 to represent at-rest and heavy breathing rates, respectively. Laminar particle trajectory simulations were used to determine the upstream area, also known as the critical area, where particles would be inhaled. These areas were used to compute aspiration efficiencies for facing the wind. Significant differences were found in both vertical velocity estimates and the location of the critical area between the three models. However, differences in aspiration efficiencies between the three forms were <8.8% over all particle sizes, indicating that there is little difference in aspiration efficiency between torso models.
PMCID: PMC3634334  PMID: 23006817
aerosols; computational fluid dynamics; dust sampling conventions; inhalable dust
6.  Pulmonary carcinoid tumors and asbestos exposure 
Annals of Occupational Hygiene  2012;56(7):789-795.
The hypothesis that asbestos exposure may have more specific associations with particular histological types of lung cancer remains controversial. The aim of this study was to analyze the relationships between asbestos exposure and pulmonary carcinoid tumors.
A retrospective case-control study was conducted in 28 cases undergoing surgery for pulmonary carcinoid tumors and aged over 40 years, and in 56 controls with lung cancer of a different histological type, matched for gender and age, from 1994 to 1999, recruited in 2 hospitals in the region of Paris. Asbestos exposure was assessed via expertise of a standardized occupational questionnaire and mineralogical analysis of lung tissue, with quantification of asbestos bodies (AB).
Definite asbestos exposure was identified in 25% of cases and 14% of controls (ns). Cumulative asbestos exposure was significantly higher in cases than in controls (p<0.05), and results of the quantification of AB tended to be higher in cases than in controls (24% and 9% had more than 1,000 AB/g dry lung tissue, respectively, p=0.09). Mean cumulative smoking was lower in cases than in controls (p<0.05).
This study argues in favor of a relationship between asbestos exposure and certain pulmonary carcinoid tumors.
PMCID: PMC3925096  PMID: 22562831
Adult; Aged; Asbestos; toxicity; Carcinoid Tumor; etiology; pathology; Case-Control Studies; Female; Humans; Lung Neoplasms; etiology; pathology; Male; Middle Aged; Occupational Diseases; etiology; pathology; Occupational Exposure; adverse effects; analysis; Paris; Questionnaires; Retrospective Studies; asbestos; lung cancer; pulmonary carcinoid tumor; occupational exposure
7.  Rapid Detection of Transition Metals in Welding Fumes Using Paper-Based Analytical Devices 
Annals of Occupational Hygiene  2014;58(4):413-423.
Metals in particulate matter (PM) are considered a driving factor for many pathologies. Despite the hazards associated with particulate metals, personal exposures for at-risk workers are rarely assessed due to the cost and effort associated with monitoring. As a result, routine exposure assessments are performed for only a small fraction of the exposed workforce. The objective of this research was to evaluate a relatively new technology, microfluidic paper-based analytical devices (µPADs), for measuring the metals content in welding fumes. Fumes from three common welding techniques (shielded metal arc, metal inert gas, and tungsten inert gas welding) were sampled in two welding shops. Concentrations of acid-extractable Fe, Cu, Ni, and Cr were measured and independently verified using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results from the µPAD sensors agreed well with ICP-OES analysis; the two methods gave statistically similar results in >80% of the samples analyzed. Analytical costs for the µPAD technique were ~50 times lower than market-rate costs with ICP-OES. Further, the µPAD method was capable of providing same-day results (as opposed several weeks for ICP laboratory analysis). Results of this work suggest that µPAD sensors are a viable, yet inexpensive alternative to traditional analytic methods for transition metals in welding fume PM. These sensors have potential to enable substantially higher levels of hazard surveillance for a given resource cost, especially in resource-limited environments.
PMCID: PMC3979282  PMID: 24515892
µPADs; chromium; colorimetric detection; exposure; iron; low cost; nickel
9.  Collection Efficiencies of High Flow Rate Personal Respirable Samplers When Measuring Arizona Road Dust and Analysis of Quartz by X-ray Diffraction 
Annals of Occupational Hygiene  2014;58(4):512-523.
Prolonged exposure to respirable crystalline silica (RCS) causes silicosis and is also considered a cause of cancer. To meet emerging needs for precise measurements of RCS, from shorter sampling periods (<4h) and lower air concentrations, collaborative work was done to assess the differences between personal respirable samplers at higher flow rates. The performance of FSP10, GK2.69, and CIP 10 R samplers were compared with that of the Safety In Mines Personal Dust Sampler (SIMPEDS) sampler as a reference, which is commonly used in the UK for the measurement of RCS. In addition, the performance of the FSP10 and GK 2.69 samplers were compared; at the nominal flow rates recommended by the manufacturers of 10 and 4.2 l · min−1 and with flow rates proposed by the National Institute for Occupational Safety and Health of 11.2 and 4.4 l · min−1. Samplers were exposed to aerosols of ultrafine and medium grades of Arizona road dust (ARD) generated in a calm air chamber. All analyses for RCS in this study were performed at the Health and Safety Laboratory. The difference in flow rates for the GK2.69 is small and does not result in a substantial difference in collection efficiency for the dusts tested, while the performance of the FSP10 at 11.2 l · min−1 was more comparable with samples from the SIMPEDS. Conversely, the GK2.69 collected proportionately more crystalline silica in the respirable dust than other samplers, which then produced RCS results most comparable with the SIMPEDS. The CIP 10 R collected less ultrafine ARD than other samplers, as might be expected based on earlier performance evaluations. The higher flow rate for the FSP10 should be an added advantage for task-specific sampling or when measuring air concentrations less than current occupational exposure limits.
PMCID: PMC3979280  PMID: 24470535
Arizona road dust; CIP 10 R; FSP10; GK2.69; quartz; respirable; sampler; silica; SIMPEDS; x-ray diffraction; XRD
10.  SWeRF—A Method for Estimating the Relevant Fine Particle Fraction in Bulk Materials for Classification and Labelling Purposes 
Annals of Occupational Hygiene  2014;58(4):501-511.
In accordance with the European regulation for classification, labelling and packaging of substances and mixtures (CLP) as well as the criteria as set out in the Globally Harmonized System (GHS), fine fraction of crystalline silica (CS) has been classified as a specific target organ toxicity, the specific organ in this case being the lung. Generic cut-off values for products containing a fine fraction of CS trigger the need for a method for the quantification of the fine fraction of CS in bulk materials. This article describes the so-called SWeRF method, the size-weighted relevant fine fraction. The SWeRF method combines the particle size distribution of a powder with probability factors from the EN 481 standard and allows the relevant fine fraction of a material to be calculated. The SWeRF method has been validated with a number of industrial minerals. This will enable manufacturers and blenders to apply the CLP and GHS criteria for the classification of mineral products containing RCS a fine fraction of CS.
PMCID: PMC3979281  PMID: 24389081
CLP; crystalline silica; fine fraction of crystalline silica; GHS; industrial minerals; quartz; SWeRF
11.  Sensitivity Analyses of Exposure Estimates from a Quantitative Job-exposure Matrix (SYN-JEM) for Use in Community-based Studies 
Annals of Occupational Hygiene  2012;57(1):98-106.
Objectives: We describe the elaboration and sensitivity analyses of a quantitative job-exposure matrix (SYN-JEM) for respirable crystalline silica (RCS). The aim was to gain insight into the robustness of the SYN-JEM RCS estimates based on critical decisions taken in the elaboration process.
Methods: SYN-JEM for RCS exposure consists of three axes (job, region, and year) based on estimates derived from a previously developed statistical model. To elaborate SYN-JEM, several decisions were taken: i.e. the application of (i) a single time trend; (ii) region-specific adjustments in RCS exposure; and (iii) a prior job-specific exposure level (by the semi-quantitative DOM-JEM), with an override of 0 mg/m3 for jobs a priori defined as non-exposed. Furthermore, we assumed that exposure levels reached a ceiling in 1960 and remained constant prior to this date. We applied SYN-JEM to the occupational histories of subjects from a large international pooled community-based case–control study. Cumulative exposure levels derived with SYN-JEM were compared with those from alternative models, described by Pearson correlation (Rp) and differences in unit of exposure (mg/m3-year). Alternative models concerned changes in application of job- and region-specific estimates and exposure ceiling, and omitting the a priori exposure ranking.
Results: Cumulative exposure levels for the study subjects ranged from 0.01 to 60 mg/m3-years, with a median of 1.76 mg/m3-years. Exposure levels derived from SYN-JEM and alternative models were overall highly correlated (Rp > 0.90), although somewhat lower when omitting the region estimate (Rp = 0.80) or not taking into account the assigned semi-quantitative exposure level (Rp = 0.65). Modification of the time trend (i.e. exposure ceiling at 1950 or 1970, or assuming a decline before 1960) caused the largest changes in absolute exposure levels (26–33% difference), but without changing the relative ranking (Rp = 0.99).
Conclusions: Exposure estimates derived from SYN-JEM appeared to be plausible compared with (historical) levels described in the literature. Decisions taken in the development of SYN-JEM did not critically change the cumulative exposure levels. The influence of region-specific estimates needs to be explored in future risk analyses.
PMCID: PMC3589949  PMID: 22805750
exposure assessment;; silica;; general population;; occupational;; retrospective; silica
12.  Workplace Measurements by the US Occupational Safety and Health Administration since 1979: Descriptive Analysis and Potential Uses for Exposure Assessment 
Annals of Occupational Hygiene  2012;57(1):77-97.
: Inspectors from the US Occupational Safety and Health Administration (OSHA) have been collecting industrial hygiene samples since 1972 to verify compliance with Permissible Exposure Limits. Starting in 1979, these measurements were computerized into the Integrated Management Information System (IMIS). In 2010, a dataset of over 1 million personal sample results analysed at OSHA’s central laboratory in Salt Lake City [Chemical Exposure Health Data (CEHD)], only partially overlapping the IMIS database, was placed into public domain via the internet. We undertook this study to inform potential users about the relationship between this newly available OSHA data and IMIS and to offer insight about the opportunities and challenges associated with the use of OSHA measurement data for occupational exposure assessment.
: We conducted a literature review of previous uses of IMIS in occupational health research and performed a descriptive analysis of the data recently made available and compared them to the IMIS database for lead, the most frequently sampled agent.
: The literature review yielded 29 studies reporting use of IMIS data, but none using the CEHD data. Most studies focused on a single contaminant, with silica and lead being most frequently analysed. Sixteen studies addressed potential bias in IMIS, mostly by examining the association between exposure levels and ancillary information. Although no biases of appreciable magnitude were consistently reported across studies and agents, these assessments may have been obscured by selective under-reporting of non-detectable measurements. The CEHD data comprised 1 450 836 records from 1984 to 2009, not counting analytical blanks and erroneous records. Seventy eight agents with >1000 personal samples yielded 1 037 367 records. Unlike IMIS, which contain administrative information (company size, job description), ancillary information in the CEHD data is mostly analytical. When the IMIS and CEHD measurements of lead were merged, 23 033 (39.2%) records were in common to both IMIS and CEHD datasets, 10 681 (18.2%) records were only in IMIS, and 25 012 (42.6%) records were only in the CEHD database. While IMIS-only records represent data analysed in other laboratories, CEHD-only records suggest partial reporting of sampling results by OSHA inspectors into IMIS. For lead, the percentage of non-detects in the CEHD-only data was 71% compared to 42% and 46% in the both-IMIS-CEHD and IMIS-only datasets, respectively, suggesting differential under-reporting of non-detects in IMIS.
: IMIS and the CEHD datasets represent the biggest source of multi-industry exposure data in the USA and should be considered as a valuable source of information for occupational exposure assessment. The lack of empirical data on biases, adequate interpretation of non-detects in OSHA data, complicated by suspected differential under-reporting, remain the principal challenges to the valid estimation of average exposure conditions. We advocate additional comparisons between IMIS and CEHD data and discuss analytical strategies that may play a key role in meeting these challenges.
PMCID: PMC3589950  PMID: 22952385
database; exposure reconstruction; IMIS; occupational hygiene
13.  The Effect of Working Position on Trunk Posture and Exertion for Routine Nursing Tasks: An Experimental Study 
Annals of Occupational Hygiene  2013;58(3):317-325.
To examine the influence of the two following factors on the proportion of time that nurses spend in a forward-bending trunk posture: (i) the bed height during basic care activities at the bedside and (ii) the work method during basic care activities in the bathroom. A further aim was to examine the connection between the proportion of time spent in a forward-bending posture and the perceived exertion.
Twelve nurses in a geriatric nursing home each performed a standardized care routine at the bedside and in the bathroom. The CUELA (German abbreviation for ‘computer-assisted recording and long-term analysis of musculoskeletal loads’) measuring system was used to record all trunk inclinations. Each participant conducted three tests with the bed at different heights (knee height, thigh height, and hip height) and in the bathroom, three tests were performed with different work methods (standing, kneeling, and sitting). After each test, participants rated their perceived exertion on the 15-point Borg scale (6 = no exertion at all and 20 = exhaustion).
If the bed was raised from knee to thigh level, the proportion of time spent in an upright position increased by 8.2% points. However, the effect was not significant (P = 0.193). Only when the bed was raised to hip height, there was a significant increase of 19.8% points (reference: thigh level; P = 0.003) and 28.0% points (reference: knee height; P < 0.001). Bathroom tests: compared with the standing work method, the kneeling and sitting work methods led to a significant increase in the proportion of time spent in an upright posture, by 19.4% points (P = 0.003) and 25.7% points (P < 0.001), respectively. The greater the proportion of time spent in an upright position, the lower the Borg rating (P < 0.001) awarded.
The higher the proportion of time that nursing personnel work in an upright position, the less strenuous they perceive the work to be. Raising the bed to hip height and using a stool in the bathroom significantly increase the proportion of time that nursing personnel work in an upright position. Nursing staff can spend a considerably greater proportion of their time in an ergonomic posture if stools and height-adjustable beds are provided in healthcare institutions.
PMCID: PMC3954518  PMID: 24371043
bed height; bending; musculoskeletal disorders; nursing; perceived exertion; trunk posture
14.  Statistical Performance of Observational Work Sampling for Assessment of Categorical Exposure Variables: A Simulation Approach Illustrated Using PATH Data 
Annals of Occupational Hygiene  2013;58(3):294-316.
Observational work sampling is often used in occupational studies to assess categorical biomechanical exposures and occurrence of specific work tasks. The statistical performance of data obtained by work sampling is, however, not well understood, impeding informed measurement strategy design. The purpose of this study was to develop a procedure for assessing the statistical properties of work sampling strategies evaluating categorical exposure variables and to illustrate the usefulness of this procedure to examine bias and precision of exposure estimates from samples of different sizes.
From a parent data set of observations on 10 construction workers performing a single operation, the probabilities were determined for each worker of performing four component tasks and working in four mutually exclusive trunk posture categories (neutral, mild flexion, severe flexion, twisted). Using these probabilities, 5000 simulated data sets were created via probability-based resampling for each of six sampling strategies, ranging from 300 to 4500 observations. For each strategy, mean exposure and exposure variability metrics were calculated at both the operation level and task level and for each metric, bias and precision were assessed across the 5000 simulations.
Estimates of exposure variability were substantially more uncertain at all sample sizes than estimates of mean exposures and task proportions. Estimates at small sample sizes were also biased. With only 600 samples, proportions of the different tasks and of working with a neutral trunk posture (the most common) were within 10% of the true target value in at least 80% of all the simulated data sets; rarer exposures required at least 1500 samples. For most task-level mean exposure variables and for all operation-level and task-level estimates of exposure variability, performance was low, even with 4500 samples. In general, the precision of mean exposure estimates did not depend on the exposure variability between workers.
The suggested probability-based simulation approach proved to be versatile and generally suitable for assessing bias and precision of data collection strategies using work sampling to estimate categorical data. The approach can be used in both real and hypothetical scenarios, in ergonomics, as well as in other areas of occupational epidemiology and intervention research. The reported statistical properties associated with sample size are likely widely relevant to studies using work sampling to assess categorical variables.
PMCID: PMC3954517  PMID: 24353010
epidemiology; ergonomics; exposure assessment methodology; precision; statistical efficiency; working postures
15.  Biomonitoring Hexamethylene Diisocyanate (HDI) Exposure Based on Serum Levels of HDI-Specific IgG 
Annals of Occupational Hygiene  2012;56(8):901-910.
Isocyanate chemicals essential for polyurethane production are widely used industrially, and are increasingly found in consumer products. Asthma and other adverse health effects of isocyanates are well-documented and exposure surveillance is crucial to disease prevention. Hexamethylene diisocyanate (HDI)-specific serum immunoglobulin G (IgG) was evaluated as an exposure biomarker among workers at a US Air Force Air Logistics Center, which includes a large aircraft maintenance facility.
HDI-specific IgG (HDI-IgG) titers in serum samples (n = 74) were measured using an enzyme-linked immunosorbent assay based upon the biuret form of HDI conjugated to human albumin. Information on personal protective equipment (PPE), work location/tasks, smoking, asthma history, basic demographics, and HDI skin exposure was obtained through questionnaire.
HDI-specific serum IgG levels were elevated in n = 17 (23%) of the workers studied. The prevalence and/or end-titer of the HDI-IgG was significantly (P < 0.05) associated with specific job titles, self-reported skin exposure, night-shift work, and respirator use, but not atopy, asthma, or other demographic information. The highest titers were localized to specific worksites (C-130 painting), while other worksites (generator painting) had no or few workers with detectable HDI-IgG.
HDI-specific immune responses (IgG) provide a practical biomarker to aid in exposure surveillance and ongoing industrial hygiene efforts. The strategy may supplement current air sampling approaches, which do not assess exposures via skin, or variability in PPE use or effectiveness. The approach may also be applicable to evaluating isocyanate exposures in other settings, and may extend to other chemical allergens.
PMCID: PMC3471419  PMID: 22449630
biomarker; exposure; HDI; hygiene; occupational
16.  Organic and Elemental Carbon Filter Sets: Preparation Method and Interlaboratory Results 
Annals of Occupational Hygiene  2012;56(8):959-967.
Carbonaceous aerosols play an important role in climate, visibility, air quality, and human health effects, and they have been routinely monitored in workplace and environmental settings. Different thermal analysis methods have been applied to determine the carbon content of carbonaceous aerosols. Good agreement between results for total carbon (TC) generally has been found, but the organic and elemental carbon (OC and EC) fractions determined by different methods often disagree. Measurement uncertainty is mainly due to pyrolysis and charring of OC sample components. Lack of reference materials has impeded progress on method standardization and understanding method biases. A relatively simple method for generating matched filter sets having known OC–EC contents is reported. After generation and analysis of each set to confirm agreement between filters, the filter sets were distributed to six laboratories for an interlaboratory comparison. Analytical results indicate a uniform carbon distribution for the filter sets and good agreement between the participating laboratories. Relative standard deviations (RSDs) for mean TC (OC + EC), OC, and EC results for seven laboratories were <10, 11, and 12% (respectively). Except for one EC result (RSD = 16%), RSDs reported by individual laboratories for TC, OC, and EC were <12%. The method of filter generation is generally applicable and reproducible. Depending on the application, different filter loadings and types of OC materials can be employed. Matched filter sets prepared by the described approach can be used for determining the accuracy of OC–EC methods and thereby contribute to method standardization.
PMCID: PMC3577040  PMID: 22459320
black carbon; carbonaceous aerosol; elemental carbon; organic carbon; particulate matter; ultrafine
17.  Usability of a Daily Noise Exposure Monitoring Device for Industrial Workers 
Annals of Occupational Hygiene  2012;56(8):925-933.
Usability is an important but often overlooked aspect of personal protective equipment technology. As part of a worksite intervention trial of a new technology for prevention of noise-induced hearing loss that allows workers to monitor their noise exposure inside of hearing protection on a daily basis, we studied the usability of the daily noise exposure monitoring device.
We conducted surveys and focus groups for workers enrolled in an intervention trial of daily use of a noise dosimeter with a microphone fitted inside of an individual’s hearing protector (QuietDose). Volunteers completed a baseline and annual survey that included questions about perceived usability of the QuietDose device. Responses to usability questions on the annual survey were abstracted and compared to whether the individual was still using the device. Finally, 16 in-depth focus groups were conducted with subjects to qualitatively explore common themes regarding the usability of the technology.
Reported problems downloading data or starting and stopping the monitoring device and/or ear discomfort were associated with whether individuals chose to continue monitoring and downloading their noise exposure data. Perceived benefits of the technology included the perception that it could help preserve hearing.
A novel technology that allows workers to record noise exposures inside of hearing protectors on a daily basis has been developed. Current users of the device report positive perception about how the device is helping them prevent noise-induced hearing loss. However, in its current version, users reported a number of usability barriers that are associated with stopping use of the device. These barriers to use should be addressed as the technology progresses.
PMCID: PMC3656687  PMID: 22459319
18.  Assessment of Swine Worker Exposures to Dust and Endotoxin during Hog Load-Out and Power Washing 
Annals of Occupational Hygiene  2012;56(7):843-851.
Field measurements of personal and area dust and endotoxin concentrations were obtained while agricultural workers performed two work tasks that have been previously unreported: hog load-out and swine building power washing. Hog load-out involves moving hogs from their pens in finishing buildings into a truck for transport to a meat processor. High pressure power washing is conducted for sanitation purposes after a building has been emptied of hogs to remove surface and floor debris. This debri consists of feed, feces, and hog dander as dust or an encrusted form. The hog load-out process necessarily increases pig activity which is known to increase airborne dust concentrations. An unintended consequence of power washing is that the material covering surfaces is forcibly ejected into the atmosphere, creating the potential for a highly concentrated aerosol exposure to workers. The load-out process resulted in a median personal inhalable mass concentration of 7.14 mg m− 3 and median endotoxin concentration of 12 150 endotoxin units (EU) m− 3. When converted to an 8-h time-weighted average for a ‘total’ sampler, one of the 19 samples exceeded a regulatory limit of 15 mg m− 3. An impinger was used to sample power washing endotoxin concentrations, which resulted in a median personal concentration of 40 350 EU m− 3. These concentrations were among the highest found in the literature for any occupation. With the lack of engineering controls present to reduce airborne contaminant concentrations in swine buildings, either respirator use or a reduction in exposure time is recommended while performing these tasks.
PMCID: PMC3415068  PMID: 22425653
endotoxin; impinger; finishing building; power washing; swine
19.  Work Inside Ocean Freight Containers—Personal Exposure to Off-Gassing Chemicals 
Annals of Occupational Hygiene  2013;57(9):1128-1137.
More than 500 million ocean freight container units are shipped annually between countries and continents. Residual levels of fumigants, as well as naturally occurring off-gassing chemicals emanating from the goods, constitute safety risks, which may affect uniformed workers upon entering the container. The aim of this study was to assess workers’ exposure during stripping of containers and is the first study of its kind. First, an experimental tracer gas method was investigated to determine its usefulness to approximate real exposures from gaseous fumigants and off-gassing volatile organic compounds (VOCs). Nitrous oxide was injected and left to distribute in the closed containers. The distribution of the tracer gas and initial (arrival) concentrations of off-gassing volatiles were measured prior to opening the containers. Second, personal exposure (breathing zone) and work zone air monitoring of both tracer gas and VOCs were carried out during stripping. Adsorbent tubes, bag samples, and direct-readings instruments (photoionization detector and Fourier transform infrared spectrometry) were used. The distribution studies with nitrous oxide, and the high correlation between the former and VOCs (r 2 ~ 0.8) during stripping, showed that the tracer gas method may well be used to approximate real exposures in containers. The average breathing zone and work zone concentrations during stripping of naturally ventilated 40-foot containers were 1–7% of the arrival concentrations; however, peaks up to 70% were seen during opening. Even if average exposures during stripping are significantly lower than arrival concentrations, they may still represent serious violations of occupational exposure limits in high-risk containers. The results from this and previous studies illustrate the need to establish practices for the safe handling of ocean freight containers. Until comprehensive recommendations are in place, personnel that need to enter such containers should, in addition to appropriate personal protective equipment, have access to equipment for measuring contaminants and for applying forced ventilation when necessary.
PMCID: PMC3820301  PMID: 23825354
confined space; exposure assessment; fumigation; prevention; sea container
20.  Asbestos-related diseases in automobile mechanics 
Annals of Occupational Hygiene  2011;56(1):55-60.
Automobile mechanics have been exposed to asbestos in the past, mainly due to the presence of chrysotile asbestos in brakes and clutches. Despite the large number of automobile mechanics, little is known about the non-malignant respiratory diseases observed in this population. The aim of this retrospective multicenter study was to analyze the frequency of pleural and parenchymal abnormalities on HRCT in a population of automobile mechanics.
The study population consisted of 103 automobile mechanics with no other source of occupational exposure to asbestos, referred to three occupational health departments in the Paris area for systematic screening of asbestos–related diseases. All subjects were examined by HRCT and all images were reviewed separately by two independent readers, with further consensus in the case of disagreement. Multiple logistic regression models were constructed to investigate factors associated with pleural plaques.
Pleural plaques were observed in 5 cases (4.9%) and interstitial abnormalities consistent with asbestosis were observed in 1 case. After adjustment for age, smoking status, and a history of non-asbestos-related respiratory diseases, multiple logistic regression models showed a significant association between the duration of exposure to asbestos and pleural plaques.
The asbestos exposure experienced by automobile mechanics may lead to pleural plaques. The low prevalence of non-malignant asbestos-related diseases, using a very sensitive diagnostic tool, is in favor of a low cumulative exposure to asbestos in this population of workers.
PMCID: PMC3678990  PMID: 21965465
Adult; Asbestos; toxicity; Automobiles; Female; Humans; Logistic Models; Lung Diseases; epidemiology; radiography; Male; Mechanics; Middle Aged; Occupational Diseases; epidemiology; radiography; Occupational Exposure; adverse effects; Paris; Pleural Diseases; epidemiology; radiography; Prevalence; Retrospective Studies; Time Factors; Tomography, X-Ray Computed; methods; Young Adult; asbestos; pleural plaques; automobile mechanics; HRCT
21.  Tensile Properties and Integrity of Clean Room and Low-Modulus Disposable Nitrile Gloves: A Comparison of Two Dissimilar Glove Types 
Annals of Occupational Hygiene  2011;56(4):450-457.
The selection of disposable nitrile exam gloves is complicated by (i) the availability of several types or formulations, (ii) product variability, and (iii) an inability of common quality control tests to detect small holes in the fingers. Differences in polymer formulation (e.g. filler and plasticizer/oil content) and tensile properties are expected to account for much of the observed variability in performance.
This study evaluated the tensile properties and integrity (leak failure rates) of two glove choices assumed to contain different amounts of plasticizers/oils. The primary aims were to determine if the tensile properties and integrity differed and if associations existed among these factors. Additional physical and chemical properties were evaluated.
Six clean room and five low-modulus products were evaluated using the American Society for Testing and Materials Method D412 and a modified water-leak test to detect holes capable of passing a virus or chemical agent.
Significant differences in the leak failure rates and tensile properties existed between the two glove types (P ≤ 0.05). The clean room gloves were about three times more likely to have leak failures (chi-square; P = 0.001). No correlation was observed between leak failures and tensile properties. Solvent extract, an indication of added plasticizer/oil, was not associated with leak failures. However, gloves with a maximum modulus <4 MPa or area density (AD) <11 g cm−2 were about four times less likely to leak.
On average, the low-modulus gloves were a better choice for protection against aqueous chemical or biological penetration. The observed variability between glove products indicated that glove selection cannot rely solely on glove type or manufacturer labeling. Measures of modulus and AD may aid in the selection process, in contrast with common measures of tensile strength and elongation at break.
PMCID: PMC3324482  PMID: 22201179
chemical protective clothing; exam gloves; penetration; PPE; water-leak test
22.  Functionality Based Detection of Airborne Engineered Nanoparticles in Quasi Real Time: A New Type of Detector and a New Metric 
Annals of Occupational Hygiene  2013;57(7):842-852.
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.
PMCID: PMC3746458  PMID: 23504803
background distinction; catalytic activity concentration; engineered nanoparticles; functionality based detection; quasi real time
23.  Occupational Exposure and New-onset Asthma in a Population-based Study in Northern Europe (RHINE) 
Annals of Occupational Hygiene  2012;57(4):482-492.
In a large population-based study among adults in northern Europe the relation between occupational exposure and new-onset asthma was studied.
The study comprised 13 284 subjects born between 1945 and 1973, who answered a questionnaire 1989–1992 and again 1999–2001. Asthma was defined as ‘Asthma diagnosed by a physician’ with reported year of diagnose. Hazard ratios (HR), for new-onset adult asthma during 1980–2000, were calculated using a modified job-exposure matrix as well as high-risk occupations in Cox regression models. The analyses were made separately for men and women and were also stratified for atopy.
During the observation period there were 429 subjects with new-onset asthma with an asthma incidence of 1.3 cases per 1000 person-years for men and 2.4 for women. A significant increase in new-onset asthma was seen for men exposed to plant-associated antigens (HR = 3.6; 95% CI [confidence interval] = 1.4–9.0), epoxy (HR = 2.4; 95% CI = 1.3–4.5), diisocyanates (HR = 2.1; 95% CI = 1.2–3.7) and accidental peak exposures to irritants (HR = 2.4; 95% CI = 1.3–4.7). Both men and women exposed to cleaning agents had an increased asthma risk. When stratifying for atopy an increased asthma risk were seen in non-atopic men exposed to acrylates (HR = 3.3; 95% CI = 1.4–7.5), epoxy compounds (HR = 3.6; 95% CI = 1.6–7.9), diisocyanates and accidental peak exposures to irritants (HR = 3.0; 95% CI = 1.2–7.2). Population attributable risk for occupational asthma was 14% for men and 7% for women.
This population-based study showed that men exposed to epoxy, diisocyanates and acrylates had an increased risk of new-onset asthma. Non-atopics seemed to be at higher risk than atopics, except for exposure to high molecular weight agents. Increased asthma risks among cleaners, spray painters, plumbers, and hairdressers were confirmed.
PMCID: PMC3622438  PMID: 23204511
Atopics and non-atopics; high molecular weight agent; high-risk occupations; irritating agents;  job-exposure matrix; low molecualr weight agent; occupational asthma;  population attributable risk
24.  Inflammatory Markers in Blood and Exhaled Air after Short-Term Exposure to Cooking Fumes 
Annals of Occupational Hygiene  2012;57(2):230-239.
Cooking fumes contain aldehydes, alkanoic acids, polycyclic aromatic hydrocarbons, and heterocyclic compounds. The inhalation of cooking fumes entails a risk of deleterious health effects. The aim of this study was to see if the inhalation of cooking fumes alters the expression of inflammatory reactions in the bronchial mucosa and its subsequent systemic inflammatory response in blood biomarkers.
Twenty-four healthy volunteers stayed in a model kitchen on two different occasions for 2 or 4h. On the first occasion, there was only exposure to normal air, and on the second, there was exposure to controlled levels of cooking fumes. On each occasion, samples of blood, exhaled air, and exhaled breath condensate (EBC) were taken three times in 24h and inflammatory markers were measured from all samples.
There was an increase in the concentration of the d-dimer in blood from 0.27 to 0.28mg ml–1 on the morning after exposure to cooking fumes compared with the levels the morning before (P-value = 0.004). There was also a trend of an increase in interleukin (IL)-6 in blood, ethane in exhaled air, and IL-1β in EBC after exposure to cooking fumes. In a sub-analysis of 12 subjects, there was also an increase in the levels of ethane—from 2.83 parts per billion (ppb) on the morning before exposure to cooking fumes to 3.53 ppb on the morning after exposure (P = 0.013)—and IL-1β—from 1.04 on the morning before exposure to cooking fumes to 1.39 pg ml–1 immediately after (P = 0.024).
In our experimental setting, we were able to unveil only small changes in the levels of inflammatory markers in exhaled air and in blood after short-term exposure to moderate concentrations of cooking fumes.
PMCID: PMC3567812  PMID: 23179989
cooking fume; exposure; human experiment; inflammation; inhalation
25.  Comparative Emissions of Random Orbital Sanding between Conventional and Self-Generated Vacuum Systems 
Annals of Occupational Hygiene  2012;57(2):221-229.
Conventional abrasive sanding generates high concentrations of particles. Depending on the substrate being abraded and exposure duration, overexposure to the particles can cause negative health effects ranging from respiratory irritation to cancer. The goal of this study was to understand the differences in particle emissions between a conventional random orbital sanding system and a self-generated vacuum random orbital sanding system with attached particle filtration bag. Particle concentrations were sampled for each system in a controlled test chamber for oak wood, chromate painted (hexavalent chromium) steel panels, and gel-coated (titanium dioxide) fiberglass panels using a Gesamtstaub-Probenahmesystem (GSP) sampler at three different locations adjacent to the sanding. Elevated concentrations were reported for all particles in the samples collected during conventional sanding. The geometric mean concentration ratios for the three substrates ranged from 320 to 4640 times greater for the conventional sanding system than the self-generated vacuum sanding system. The differences in the particle concentration generated by the two sanding systems were statistically significant with the two sample t-test (P < 0.0001) for all three substances. The data suggest that workers using conventional sanding systems could utilize the self-generated vacuum sanding system technology to potentially reduce exposure to particles and mitigate negative health effects.
PMCID: PMC3567810  PMID: 23065674
GSP sampler; hexavalent chromium; oak wood; random orbital sanding; titanium dioxide

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