title: Variability in dust exposure in a cement factory in Tanzania.
abstract: Dust exposure levels were studied in a cement factory in Dar es Salaam, Tanzania, as part of an epidemiological study assessing chronic respiratory health effects. One hundred and twenty personal 'total' dust samples were collected from 80 randomly selected workers from eight a priori occupational groups (OGs) based on work areas using a 37 mm Millipore sampler. The between-group, within-group and within-worker variances were determined to assess the contrast in exposure level between the OGs and to estimate the attenuation and standard error of the theoretical exposure-response slope. Using mixed-effect model estimates, the probability of overexposure relative to the occupational exposure limit (OEL) was assessed for each OG. The geometric means of total dust exposure were higher in the cranes (38.64 mg m(-3)), packing (21.30 mg m(-3)) and crusher (13.48 mg m(-3)) than in the cement mill (3.23 mg m(-3)), kiln (2.87 mg m(-3)), raw mill (1.85 mg m(-3)), maintenance (1.16 mg m(-3)) and administration (0.29 mg m(-3)). The a priori grouping scheme seems to be an efficient scheme because of the high contrast in exposure level between the OGs (0.78) and minimal attenuation of the theoretical exposure-response slope (1.0%). When using the reduced mixed-effect model, the probabilities of overexposure () relative to the OEL of 10 mg m(-3) for total cement dust were higher in the crane (96%), packing (88%) and crusher (73%) than in the cement mill (16%), kiln (14%), raw mill (5%), maintenance (2%) and administration (0.01%).
authors.affiliation: Centre for International Health, Faculty of Medicine, University of Bergen, Armauer Hansens Hus, N-5021 Bergen, Norway. jmwaiselage@yahoo.com
authors.forename: Julius
authors.initials: J
authors.lastname: Mwaiselage
authors.forename: Magne
authors.initials: M
authors.lastname: Bråtveit
authors.forename: Bente
authors.initials: B
authors.lastname: Moen
authors.forename: Michael
authors.initials: M
authors.lastname: Yost
mesh_terms: D003252:Construction Materials; D003430:Cross-Sectional Studies; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis*; D016273:Occupational Exposure / Q000032:analysis*
chemical_list: D004391:Dust