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The diesel exhaust in miners study: I. Overview of the exposure assessment process.
Ann Occup Hyg. 2010 Oct; 54(7):728-46.AO

Abstract

This report provides an overview of the exposure assessment process for an epidemiologic study that investigated mortality, with a special focus on lung cancer, associated with diesel exhaust (DE) exposure among miners. Details of several components are provided in four other reports. A major challenge for this study was the development of quantitative estimates of historical exposures to DE. There is no single standard method for assessing the totality of DE, so respirable elemental carbon (REC), a component of DE, was selected as the primary surrogate in this study. Air monitoring surveys at seven of the eight study mining facilities were conducted between 1998 and 2001 and provided reference personal REC exposure levels and measurements for other agents and DE components in the mining environment. (The eighth facility had closed permanently prior to the surveys.) Exposure estimates were developed for mining facility/department/job/year combinations. A hierarchical grouping strategy was developed for assigning exposure levels to underground jobs [based on job titles, on the amount of time spent in various areas of the underground mine, and on similar carbon monoxide (CO, another DE component) concentrations] and to surface jobs (based on the use of, or proximity to, diesel-powered equipment). Time trends in air concentrations for underground jobs were estimated from mining facility-specific prediction models using diesel equipment horsepower, total air flow rates exhausted from the underground mines, and, because there were no historical REC measurements, historical measurements of CO. Exposures to potentially confounding agents, i.e. respirable dust, silica, radon, asbestos, and non-diesel sources of polycyclic aromatic hydrocarbons, also were assessed. Accuracy and reliability of the estimated REC exposures levels were evaluated by comparison with several smaller datasets and by development of alternative time trend models. During 1998-2001, the average measured REC exposure level by facility ranged from 40 to 384 μg m⁻³ for the underground workers and from 2 to 6 μg m⁻³ for the surface workers. For one prevalent underground job, 'miner operator', the maximum annual REC exposure estimate by facility ranged up to 685% greater than the corresponding 1998-2001 value. A comparison of the historical CO estimates from the time trend models with 1976-1977 CO measurements not used in the modeling found an overall median relative difference of 29%. Other comparisons showed similar levels of agreement. The assessment process indicated large differences in REC exposure levels over time and across the underground operations. Method evaluations indicated that the final estimates were consistent with those from alternative time trend models and demonstrated moderate to high agreement with external data.

Authors+Show Affiliations

Division of Cancer Epidemiology and Genetics, US National Cancer Institute, Bethesda, MD 20892, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Intramural
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

20876233

Citation

Stewart, Patricia A., et al. "The Diesel Exhaust in Miners Study: I. Overview of the Exposure Assessment Process." The Annals of Occupational Hygiene, vol. 54, no. 7, 2010, pp. 728-46.
Stewart PA, Coble JB, Vermeulen R, et al. The diesel exhaust in miners study: I. Overview of the exposure assessment process. Ann Occup Hyg. 2010;54(7):728-46.
Stewart, P. A., Coble, J. B., Vermeulen, R., Schleiff, P., Blair, A., Lubin, J., Attfield, M., & Silverman, D. T. (2010). The diesel exhaust in miners study: I. Overview of the exposure assessment process. The Annals of Occupational Hygiene, 54(7), 728-46. https://doi.org/10.1093/annhyg/meq022
Stewart PA, et al. The Diesel Exhaust in Miners Study: I. Overview of the Exposure Assessment Process. Ann Occup Hyg. 2010;54(7):728-46. PubMed PMID: 20876233.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The diesel exhaust in miners study: I. Overview of the exposure assessment process. AU - Stewart,Patricia A, AU - Coble,Joseph B, AU - Vermeulen,Roel, AU - Schleiff,Patricia, AU - Blair,Aaron, AU - Lubin,Jay, AU - Attfield,Michael, AU - Silverman,Debra T, Y1 - 2010/09/27/ PY - 2010/9/30/entrez PY - 2010/9/30/pubmed PY - 2011/12/13/medline SP - 728 EP - 46 JF - The Annals of occupational hygiene JO - Ann Occup Hyg VL - 54 IS - 7 N2 - This report provides an overview of the exposure assessment process for an epidemiologic study that investigated mortality, with a special focus on lung cancer, associated with diesel exhaust (DE) exposure among miners. Details of several components are provided in four other reports. A major challenge for this study was the development of quantitative estimates of historical exposures to DE. There is no single standard method for assessing the totality of DE, so respirable elemental carbon (REC), a component of DE, was selected as the primary surrogate in this study. Air monitoring surveys at seven of the eight study mining facilities were conducted between 1998 and 2001 and provided reference personal REC exposure levels and measurements for other agents and DE components in the mining environment. (The eighth facility had closed permanently prior to the surveys.) Exposure estimates were developed for mining facility/department/job/year combinations. A hierarchical grouping strategy was developed for assigning exposure levels to underground jobs [based on job titles, on the amount of time spent in various areas of the underground mine, and on similar carbon monoxide (CO, another DE component) concentrations] and to surface jobs (based on the use of, or proximity to, diesel-powered equipment). Time trends in air concentrations for underground jobs were estimated from mining facility-specific prediction models using diesel equipment horsepower, total air flow rates exhausted from the underground mines, and, because there were no historical REC measurements, historical measurements of CO. Exposures to potentially confounding agents, i.e. respirable dust, silica, radon, asbestos, and non-diesel sources of polycyclic aromatic hydrocarbons, also were assessed. Accuracy and reliability of the estimated REC exposures levels were evaluated by comparison with several smaller datasets and by development of alternative time trend models. During 1998-2001, the average measured REC exposure level by facility ranged from 40 to 384 μg m⁻³ for the underground workers and from 2 to 6 μg m⁻³ for the surface workers. For one prevalent underground job, 'miner operator', the maximum annual REC exposure estimate by facility ranged up to 685% greater than the corresponding 1998-2001 value. A comparison of the historical CO estimates from the time trend models with 1976-1977 CO measurements not used in the modeling found an overall median relative difference of 29%. Other comparisons showed similar levels of agreement. The assessment process indicated large differences in REC exposure levels over time and across the underground operations. Method evaluations indicated that the final estimates were consistent with those from alternative time trend models and demonstrated moderate to high agreement with external data. SN - 1475-3162 UR - https://www.unboundmedicine.com/medline/citation/20876233/The_diesel_exhaust_in_miners_study:_I__Overview_of_the_exposure_assessment_process_ L2 - https://academic.oup.com/annweh/article-lookup/doi/10.1093/annhyg/meq022 DB - PRIME DP - Unbound Medicine ER -