title: Cross-sectional study on respiratory morbidity in workers after exposure to synthetic amorphous silica at five German production plants: exposure assessment and exposure estimates.
abstract: OBJECTIVE
  Synthetic amorphous silicas (SASs) are nanostructured polymorphs of silicon dioxide. We compared two different exposure assessments.
  
  
  METHODS
  This study estimated cumulative exposure to inhalable SAS dust in 484 male workers from five German SAS-producing plants. Two procedures (P1 and P2) were applied. P1 was based on an expert assessment. P2 was a multiple exposure assessment (15 scenarios) anchored by a recent measurement series (1375 personal measurements of inhalable SAS dust concentration) and used expert assessments.
  
  
  RESULTS
  Cumulative exposure estimates for P1 averaged 56.9 mg/m·yrs (range, 0.1 to 419); for a selected P2 scenario, the mean was 31.8 mg/m·yrs (range, 0.4 to 480), (P < 0.0001). Averages varied between the 15 P2-scenarios from 12.6 to 109.6 mg/m·yrs. Different time trends for SAS concentrations were observed.
  
  
  CONCLUSIONS
  Both approaches suffer from considerable uncertainties that need to be considered in epidemiological studies.
authors.affiliation: From the Institute for Occupational Epidemiology and Risk Assessment of Evonik Industries AG (Mr Morfeld), Essen, Germany; Institute and Policlinic for Occupational Medicine (Mr Morfeld), Environmental Medicine and Prevention Research, University of Cologne, Cologne, Germany; Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (Mr Taeger and Mr Merget), Institute of the Ruhr-Universität Bochum (IPA), Bochum, Germany; AQura GmbH (Mr Mitura), Hanau, Germany; Wacker Chemie AG (Mr Bosch), Burghausen, Germany; Cabot Corporation (Mr Nordone), Boston, Mass; Evonik Industries (Mr Vormberg), Hanau, Germany; and Massachusetts Institute of Technology (Mr McCunney), Boston, Mass.
authors.forename: Peter
authors.initials: P
authors.lastname: Morfeld
authors.forename: Dirk
authors.initials: D
authors.lastname: Taeger
authors.forename: Heike
authors.initials: H
authors.lastname: Mitura
authors.forename: Axel
authors.initials: A
authors.lastname: Bosch
authors.forename: Adrian
authors.initials: A
authors.lastname: Nordone
authors.forename: Reinhard
authors.initials: R
authors.lastname: Vormberg
authors.forename: Robert
authors.initials: R
authors.lastname: McCunney
authors.forename: Rolf
authors.initials: R
authors.lastname: Merget
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000032:analysis*; D003430:Cross-Sectional Studies; D004391:Dust / Q000032:analysis*; D005858:Germany / Q000453:epidemiology; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000032:analysis*; D012140:Respiratory Tract Diseases / Q000139:chemically induced; D012822:Silicon Dioxide / Q000032:analysis* / Q000633:toxicity; D013223:Statistics as Topic; D055815:Young Adult
chemical_list: D000395:Air Pollutants, Occupational; D004391:Dust; D012822:Silicon Dioxide