The influences of aerosol size distribution and breath tidal volume on respirable dose estimates were examined for mouth breathing using the ACGIH/ISO/CEN criterion for respirable-equivalent aerosols. Actual tissue doses predicted from a set of pulmonary empirical deposition equations, the Heyder-Rudolf equations, were compared with deposition assumed to occur under the penetration-based respirable dust sampling criterion. Deposition estimate errors ranged from approximately 1/10- to 10-fold, with aerosol mass median aerodynamic equivalent diameter and geometric standard deviation as well as tidal volume each showing a substantial influence under appropriate conditions. These findings demonstrate that reliance on respirable aerosol sampling data obtained with devices performing on a penetration-based sampling criterion may lead to erroneous dose-response relationships in exposure standard development as well as exposure misclassification errors during epidemiological studies. A more reliable dose estimate would be obtained using devices with collection efficiency performance closely matching the alveolar deposition prediction curves of Heyder and Rudolf. We believe that if it is not currently required, the development of a deposition-based aerosol sampling methodology will soon be required for the determination and quantification of inhaled aerosol-induced adverse health effects.
{"title":"The variability of delivered dose of aerosols with the same respirable concentration but different size distributions.","authors":"N. Esmen, D. Johnson, G. Agron","doi":"10.1093/ANNHYG/MEF046","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF046","url":null,"abstract":"The influences of aerosol size distribution and breath tidal volume on respirable dose estimates were examined for mouth breathing using the ACGIH/ISO/CEN criterion for respirable-equivalent aerosols. Actual tissue doses predicted from a set of pulmonary empirical deposition equations, the Heyder-Rudolf equations, were compared with deposition assumed to occur under the penetration-based respirable dust sampling criterion. Deposition estimate errors ranged from approximately 1/10- to 10-fold, with aerosol mass median aerodynamic equivalent diameter and geometric standard deviation as well as tidal volume each showing a substantial influence under appropriate conditions. These findings demonstrate that reliance on respirable aerosol sampling data obtained with devices performing on a penetration-based sampling criterion may lead to erroneous dose-response relationships in exposure standard development as well as exposure misclassification errors during epidemiological studies. A more reliable dose estimate would be obtained using devices with collection efficiency performance closely matching the alveolar deposition prediction curves of Heyder and Rudolf. We believe that if it is not currently required, the development of a deposition-based aerosol sampling methodology will soon be required for the determination and quantification of inhaled aerosol-induced adverse health effects.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116668425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Svendsen, H. N. Jensen, Ingvill Sivertsen, A. Sjaastad
OBJECTIVES The purpose of this study was to assess exposure to fat aerosols and aldehydes in kitchens and to study the variations in exposure between different types of kitchen. METHODS Measurements were made in four hotel kitchens, two hamburger chain restaurants, 10 à la carte restaurants and three small local restaurants serving mostly fried food. The measurements were performed as personal measurements and each person carried two sampling devices connected to pumps. One pump was connected to a filter cassette with a 37 mm glassfibre filter and the other to a sampling device for aldehydes. The measurements were repeated on 3 days in each kitchen. Variables which could influence the level of exposure were recorded by the occupational hygienist. RESULTS The level of fat aerosols varied between the different types of kitchen. The highest measured level of fat aerosol was 6.6 mg/m(3), in a small local restaurant. The arithmetic mean for all the kitchens was 0.62 mg/m(3). The highest level of the sum of the aldehydes was 186 micro g/m(3) (0.186 mg/m(3)), while the arithmetic mean was 69 micro g/m(3). CONCLUSIONS The exposure to fat aerosols was modest, but could be up to 50% of the Norwegian threshold limit value (TLV) for nuisance dust (10 mg/m(3)). Fat aerosols from frying will, however, contain a mixture of heat- and water-treated fat from the meat which is being fried, hydrolysed vegetable fat and other degradation products, such as fatty acids, other organic acids and aldehydes. As a consequence of this, cooking fumes should be regarded as harmful to the lungs. The levels of formaldehyde, acetaldehyde and acrolein were well below the TLVs.
{"title":"Exposure to cooking fumes in restaurant kitchens in norway.","authors":"K. Svendsen, H. N. Jensen, Ingvill Sivertsen, A. Sjaastad","doi":"10.1093/ANNHYG/MEF045","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF045","url":null,"abstract":"OBJECTIVES\u0000The purpose of this study was to assess exposure to fat aerosols and aldehydes in kitchens and to study the variations in exposure between different types of kitchen.\u0000\u0000\u0000METHODS\u0000Measurements were made in four hotel kitchens, two hamburger chain restaurants, 10 à la carte restaurants and three small local restaurants serving mostly fried food. The measurements were performed as personal measurements and each person carried two sampling devices connected to pumps. One pump was connected to a filter cassette with a 37 mm glassfibre filter and the other to a sampling device for aldehydes. The measurements were repeated on 3 days in each kitchen. Variables which could influence the level of exposure were recorded by the occupational hygienist.\u0000\u0000\u0000RESULTS\u0000The level of fat aerosols varied between the different types of kitchen. The highest measured level of fat aerosol was 6.6 mg/m(3), in a small local restaurant. The arithmetic mean for all the kitchens was 0.62 mg/m(3). The highest level of the sum of the aldehydes was 186 micro g/m(3) (0.186 mg/m(3)), while the arithmetic mean was 69 micro g/m(3).\u0000\u0000\u0000CONCLUSIONS\u0000The exposure to fat aerosols was modest, but could be up to 50% of the Norwegian threshold limit value (TLV) for nuisance dust (10 mg/m(3)). Fat aerosols from frying will, however, contain a mixture of heat- and water-treated fat from the meat which is being fried, hydrolysed vegetable fat and other degradation products, such as fatty acids, other organic acids and aldehydes. As a consequence of this, cooking fumes should be regarded as harmful to the lungs. The levels of formaldehyde, acetaldehyde and acrolein were well below the TLVs.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116272840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper sets out a fresh approach to healthy workplaces, laying foundations to meet the demands of the new millennium. Professionals such as occupational hygienists deal with issues at the heart of the economy and society, which are beginning to attract the attention of politicians. Old disciplinary barriers must be crossed and communication improved so that healthy work is accepted as a mainstream concern, integral to sustainable development. This presents challenges both to professionals and to those with responsibilities for policy. As a first step, we need to develop an understanding of how conclusions from research can inform responsible decision making. We will not be able to design and build perfectly safe environments, but real progress can be made in the field of 'workplace health defence', using available human, technical and financial resources. A vital ingredient is partnership in the workplace, involving social partners and professionals working in collaboration.
{"title":"Partnership for sustainable healthy workplaces: Warner Lecture, British Occupational Hygiene Society, Sheffield 9 April 2002.","authors":"R. Ennals","doi":"10.1093/ANNHYG/MEF061","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF061","url":null,"abstract":"The paper sets out a fresh approach to healthy workplaces, laying foundations to meet the demands of the new millennium. Professionals such as occupational hygienists deal with issues at the heart of the economy and society, which are beginning to attract the attention of politicians. Old disciplinary barriers must be crossed and communication improved so that healthy work is accepted as a mainstream concern, integral to sustainable development. This presents challenges both to professionals and to those with responsibilities for policy. As a first step, we need to develop an understanding of how conclusions from research can inform responsible decision making. We will not be able to design and build perfectly safe environments, but real progress can be made in the field of 'workplace health defence', using available human, technical and financial resources. A vital ingredient is partnership in the workplace, involving social partners and professionals working in collaboration.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"46 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129789475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A full-scale installation which simulates a surface treatment tank provided with a push-pull ventilation system has been designed. This study examines the influence of the geometry of the push element on the capture efficiency of the system. It is observed that: (i) capture efficiency increases with the number of holes because of the continuous curtain formed, the size of the holes having no significant effect within the range studied (5-20 mm diameter); (ii) the push element is best supported on the tank wall so that no air from outside penetrates below the emitting jets because in this way the impact of the curtain on the tank occurs earlier and losses are less; (iii) the best results are obtained when the holes are directed downwards towards the tank surface at an angle of between 22 and 45 degrees.
{"title":"Influence of push element geometry on the capture efficiency of push-pull ventilation systems in surface treatment tanks.","authors":"F. Marzal, E. González, A. Miñana, A. Baeza","doi":"10.1093/ANNHYG/MEF048","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF048","url":null,"abstract":"A full-scale installation which simulates a surface treatment tank provided with a push-pull ventilation system has been designed. This study examines the influence of the geometry of the push element on the capture efficiency of the system. It is observed that: (i) capture efficiency increases with the number of holes because of the continuous curtain formed, the size of the holes having no significant effect within the range studied (5-20 mm diameter); (ii) the push element is best supported on the tank wall so that no air from outside penetrates below the emitting jets because in this way the impact of the curtain on the tank occurs earlier and losses are less; (iii) the best results are obtained when the holes are directed downwards towards the tank surface at an angle of between 22 and 45 degrees.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131542759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
OBJECTIVES Phlebotomists occupationally exposed to isopropanol (IPA) (2-propanol) and naïve controls (n = 12 per group) were exposed to the time-weighted average threshold limit value of 400 p.p.m. IPA for 4 h in an environmental chamber to investigate: (i) acute effects of sensory irritation using subjective health symptom reports and objective, physiological end-points; and (ii) differences in measured effects in relation to exposure history. METHODS Before, during and after exposure subjects gave self-reports of health complaints. During exposure subjects rated the intensity of the odor, sensory irritation and annoyance. Objective end-points of ocular hyperemia, nasal congestion, nasal secretion and respiration were obtained at various times before, during and after exposure. Results were compared with exposure to phenylethyl alcohol (PEA), a negative control for irritation, and to clean air (CA), a negative control for odor and irritation, using a within-subjects design. RESULTS Significantly higher intensity ratings of odor, irritation and annoyance were reported during the exposure to IPA, when compared with exposure to CA or PEA. Nevertheless, the overall level of reported sensory irritation to IPA was low and perceived as 'weak' on average. Health symptom ratings were not significantly elevated for IPA as compared with PEA or CA exposure. The only physiological end-point that showed a change exclusively in the IPA condition was respiration frequency: relative to baseline, respiration frequency increased in response to IPA in both groups. No differences were encountered between the occupationally exposed and the control groups. CONCLUSIONS The increase in respiration frequency in response to IPA may reflect either a reflexive change due to sensory irritation (an autonomic event) or a voluntary change in breathing in response to perception of an unpleasant, solvent-like odor (a physiological event caused by cognitive mediation). Our findings on objective end-points, including nasal and ocular sensory irritation, did not confirm subjective irritation reports. Irritation reports and odor intensity decreased, rather than increased, over time, lending credence to the cognitive argument and suggesting that the elevated subjective responses to IPA may be mediated by responses to its odor.
{"title":"Acute sensory irritation from exposure to isopropanol (2-propanol) at TLV in workers and controls: objective versus subjective effects.","authors":"M. Smeets, C. Mauté, P. Dalton","doi":"10.1093/ANNHYG/MEF054","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF054","url":null,"abstract":"OBJECTIVES\u0000Phlebotomists occupationally exposed to isopropanol (IPA) (2-propanol) and naïve controls (n = 12 per group) were exposed to the time-weighted average threshold limit value of 400 p.p.m. IPA for 4 h in an environmental chamber to investigate: (i) acute effects of sensory irritation using subjective health symptom reports and objective, physiological end-points; and (ii) differences in measured effects in relation to exposure history.\u0000\u0000\u0000METHODS\u0000Before, during and after exposure subjects gave self-reports of health complaints. During exposure subjects rated the intensity of the odor, sensory irritation and annoyance. Objective end-points of ocular hyperemia, nasal congestion, nasal secretion and respiration were obtained at various times before, during and after exposure. Results were compared with exposure to phenylethyl alcohol (PEA), a negative control for irritation, and to clean air (CA), a negative control for odor and irritation, using a within-subjects design.\u0000\u0000\u0000RESULTS\u0000Significantly higher intensity ratings of odor, irritation and annoyance were reported during the exposure to IPA, when compared with exposure to CA or PEA. Nevertheless, the overall level of reported sensory irritation to IPA was low and perceived as 'weak' on average. Health symptom ratings were not significantly elevated for IPA as compared with PEA or CA exposure. The only physiological end-point that showed a change exclusively in the IPA condition was respiration frequency: relative to baseline, respiration frequency increased in response to IPA in both groups. No differences were encountered between the occupationally exposed and the control groups.\u0000\u0000\u0000CONCLUSIONS\u0000The increase in respiration frequency in response to IPA may reflect either a reflexive change due to sensory irritation (an autonomic event) or a voluntary change in breathing in response to perception of an unpleasant, solvent-like odor (a physiological event caused by cognitive mediation). Our findings on objective end-points, including nasal and ocular sensory irritation, did not confirm subjective irritation reports. Irritation reports and odor intensity decreased, rather than increased, over time, lending credence to the cognitive argument and suggesting that the elevated subjective responses to IPA may be mediated by responses to its odor.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124945881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A critique of Bayesian methods for retrospective exposure assessment.","authors":"I. Burstyn, H. Kromhout","doi":"10.1093/ANNHYG/MEF058","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF058","url":null,"abstract":"","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122048535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Bémer, M. Lecler, R. Régnier, G. Hecht, J. Gerber
A method to measure the emission rate of an airborne pollutant source using a tracer gas was tested in the case of an aerosol source. The influence of particle deposition on the walls of a test room of 72 m3 was studied. The deposition rate of an aerosol of MgCl2 was determined by means of two methods: one based on measuring the aerosol concentration decay inside the ventilated room, the other based on calculation of the material mass balance. The concentration decay was monitored by optical counting and the aerosol mass concentration determined by means of sampling on a filter and analysis of the mass deposited by atomic absorption spectrometry. Four series of measurements were carried out. The curve giving the deposition rate according to the particle aerodynamic diameter (d(ae)) was established and shows deposition rates higher than those predicted using the model of Corner. The decay method gives the best results. The study carried out has shown that the phenomenon of deposition has little effect on the measurement of the aerosol source emission rate using a tracer gas for particles of aerodynamic diameter < 5 microm (underestimation < 25%). For particles of a greater diameter, wall deposition is an extremely limiting factor for the method, the influence of which can, however, be limited by using a test booth of small volume and keeping the sampling duration as short as possible.
{"title":"Measuring the emission rate of an aerosol source placed in a ventilated room using a tracer gas: influence of particle wall deposition.","authors":"D. Bémer, M. Lecler, R. Régnier, G. Hecht, J. Gerber","doi":"10.1093/ANNHYG/MEF031","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF031","url":null,"abstract":"A method to measure the emission rate of an airborne pollutant source using a tracer gas was tested in the case of an aerosol source. The influence of particle deposition on the walls of a test room of 72 m3 was studied. The deposition rate of an aerosol of MgCl2 was determined by means of two methods: one based on measuring the aerosol concentration decay inside the ventilated room, the other based on calculation of the material mass balance. The concentration decay was monitored by optical counting and the aerosol mass concentration determined by means of sampling on a filter and analysis of the mass deposited by atomic absorption spectrometry. Four series of measurements were carried out. The curve giving the deposition rate according to the particle aerodynamic diameter (d(ae)) was established and shows deposition rates higher than those predicted using the model of Corner. The decay method gives the best results. The study carried out has shown that the phenomenon of deposition has little effect on the measurement of the aerosol source emission rate using a tracer gas for particles of aerodynamic diameter < 5 microm (underestimation < 25%). For particles of a greater diameter, wall deposition is an extremely limiting factor for the method, the influence of which can, however, be limited by using a test booth of small volume and keeping the sampling duration as short as possible.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115850939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Studies reporting the findings of exposure to crystalline silica dust during concrete finishing in construction settings are scarce due to the dynamic nature of the activity and the existence of many confounding factors. This study was initiated to explore the issue. A total of 49 personal respirable dust samples were collected during concrete finishing while workers used hand-held grinders. Only 15 (31%) of the grinders were equipped with local exhaust ventilation (LEV) systems. The confounding factors (e.g. wind velocity, wind direction, relative humidity and ambient temperature) were determined. To make the sampling task-specific, air sampling was activated only during actual grinding. Task-specific sampling times during each work shift ranged from 10 to 200 min. The concentration of total respirable particulate ranged from 0.34 to 81 mg/m3, with a mean +/- SD of 18.6 +/- 20.4 mg/m3, and the concentration of crystalline silica in the samples ranged from 0.02 to 7.1 mg/m3, with a mean +/- SD of 1.16 +/- 1.36 mg/m3. LEV on the grinders reduced the silica dust level significantly (P < 0.01) compared to grinders without LEV. Increased wind velocity also reduced the silica dust concentration significantly (P < 0.03). Working upwind reduced the exposure to silica dust compared to working downwind, but the difference was not statistically significant. The time-weighted average concentration of silica dust in 69% of the samples exceeded the current recommended threshold limit value of 0.05 mg/m3, indicating a strong need to devise methods for controlling workers' exposure to crystalline silica dust during concrete finishing activities.
{"title":"Respirable crystalline silica dust exposure during concrete finishing (grinding) using hand-held grinders in the construction industry.","authors":"F. Akbar-khanzadeh, R. L. Brillhart","doi":"10.1093/ANNHYG/MEF043","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF043","url":null,"abstract":"Studies reporting the findings of exposure to crystalline silica dust during concrete finishing in construction settings are scarce due to the dynamic nature of the activity and the existence of many confounding factors. This study was initiated to explore the issue. A total of 49 personal respirable dust samples were collected during concrete finishing while workers used hand-held grinders. Only 15 (31%) of the grinders were equipped with local exhaust ventilation (LEV) systems. The confounding factors (e.g. wind velocity, wind direction, relative humidity and ambient temperature) were determined. To make the sampling task-specific, air sampling was activated only during actual grinding. Task-specific sampling times during each work shift ranged from 10 to 200 min. The concentration of total respirable particulate ranged from 0.34 to 81 mg/m3, with a mean +/- SD of 18.6 +/- 20.4 mg/m3, and the concentration of crystalline silica in the samples ranged from 0.02 to 7.1 mg/m3, with a mean +/- SD of 1.16 +/- 1.36 mg/m3. LEV on the grinders reduced the silica dust level significantly (P < 0.01) compared to grinders without LEV. Increased wind velocity also reduced the silica dust concentration significantly (P < 0.03). Working upwind reduced the exposure to silica dust compared to working downwind, but the difference was not statistically significant. The time-weighted average concentration of silica dust in 69% of the samples exceeded the current recommended threshold limit value of 0.05 mg/m3, indicating a strong need to devise methods for controlling workers' exposure to crystalline silica dust during concrete finishing activities.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121214948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The UK's Regular Interlaboratory Counting Exchanges (RICE) scheme provides proficiency testing for laboratories counting asbestos fibres by phase contrast optical microscopy, as in the method for measurement of airborne fibre concentrations. From 1984 to 1992, the scheme used circulations of industrial samples containing mostly chrysotile, and reference values were obtained from fibre counts by automated image analysis. In 1992, lower density (< 100 fibres/mm2) samples from asbestos clearance operations were added and the new reference values were medians of the laboratories' determinations. In extensive data from 28 recent rounds of sample exchanges, the new reference values are shown to be more reliable than the old. Average counting levels have changed, with different trends according to fibre density. In low density samples, after initial increases, the levels appear to have stabilized. Counting levels on the higher density samples show a continuing trend of approximately 0.5% decrease per round. Widening the density range may have reduced the influence of counters' preconceptions of what values are expected and so their counts on the reference samples may now better reflect their routine counting. The implications of these findings and of other new developments, such as expected new counting rules, are discussed.
{"title":"Developments in the RICE asbestos fibre counting scheme, 1992-2000. Regular Interlaboratory Counting Exchanges.","authors":"P. Brown, Alan D. Jones, B. Miller","doi":"10.1093/ANNHYG/MEF033","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF033","url":null,"abstract":"The UK's Regular Interlaboratory Counting Exchanges (RICE) scheme provides proficiency testing for laboratories counting asbestos fibres by phase contrast optical microscopy, as in the method for measurement of airborne fibre concentrations. From 1984 to 1992, the scheme used circulations of industrial samples containing mostly chrysotile, and reference values were obtained from fibre counts by automated image analysis. In 1992, lower density (< 100 fibres/mm2) samples from asbestos clearance operations were added and the new reference values were medians of the laboratories' determinations. In extensive data from 28 recent rounds of sample exchanges, the new reference values are shown to be more reliable than the old. Average counting levels have changed, with different trends according to fibre density. In low density samples, after initial increases, the levels appear to have stabilized. Counting levels on the higher density samples show a continuing trend of approximately 0.5% decrease per round. Widening the density range may have reduced the influence of counters' preconceptions of what values are expected and so their counts on the reference samples may now better reflect their routine counting. The implications of these findings and of other new developments, such as expected new counting rules, are discussed.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"46 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130772452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
OBJECTIVE At present there is no systematic observation protocol for the assessment of the multi-factorial aspects of physical exposure related to the back used within the constraints of occupational epidemiological research. In this context, a new preliminary systematic observation protocol is proposed to assess exposure to physical loading of the back using nine categories of physical risk factors: the SOPE back protocol. The objective of this study was to investigate whether the new protocol can correctly identify the level of exposure related to measured physical loading of the back. METHODS The subjects of this closed cohort study were 451 manual workers at a natural gas distribution company. The assessment of exposure was made with the protocol using groups with different job titles. The workers were followed for a 2 yr period to establish the risk of a new occurrence of complete disability related to the back (NOCD back injury) in each job grouping. RESULTS Based on the median of the total scores derived from the protocol, two levels of exposure were identified (high and low). CONCLUSION Taking into account the limitations of this study, the protocol in development may be a good tool to establish two levels of exposure to physical loading of the back in large epidemiological studies of occupational low back pain. Further research is needed to replicate these results with larger samples and to test the reliability and predictive validity of the protocol.
{"title":"Development of a systematic observation protocol of physical exposure of the back: a preliminary study.","authors":"M. Tousignant, G. Tougas, M. Rossignol, L. Goulet","doi":"10.1093/ANNHYG/MEF042","DOIUrl":"https://doi.org/10.1093/ANNHYG/MEF042","url":null,"abstract":"OBJECTIVE\u0000At present there is no systematic observation protocol for the assessment of the multi-factorial aspects of physical exposure related to the back used within the constraints of occupational epidemiological research. In this context, a new preliminary systematic observation protocol is proposed to assess exposure to physical loading of the back using nine categories of physical risk factors: the SOPE back protocol. The objective of this study was to investigate whether the new protocol can correctly identify the level of exposure related to measured physical loading of the back.\u0000\u0000\u0000METHODS\u0000The subjects of this closed cohort study were 451 manual workers at a natural gas distribution company. The assessment of exposure was made with the protocol using groups with different job titles. The workers were followed for a 2 yr period to establish the risk of a new occurrence of complete disability related to the back (NOCD back injury) in each job grouping.\u0000\u0000\u0000RESULTS\u0000Based on the median of the total scores derived from the protocol, two levels of exposure were identified (high and low).\u0000\u0000\u0000CONCLUSION\u0000Taking into account the limitations of this study, the protocol in development may be a good tool to establish two levels of exposure to physical loading of the back in large epidemiological studies of occupational low back pain. Further research is needed to replicate these results with larger samples and to test the reliability and predictive validity of the protocol.","PeriodicalId":342592,"journal":{"name":"The Annals of occupational hygiene","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127327979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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