title: Dust and gas exposure in tunnel construction work.
abstract: Personal exposures to dust and gases were measured among 189 underground construction workers who were divided into seven occupational groups performing similar tasks in similar working conditions: drill and blast crew; shaft-drilling crew; tunnel-boring machine crew; shotcreting operators; support workers; concrete workers; and electricians. Outdoor tunnel workers were included as a low-exposed reference group. The highest geometric mean (GM) exposures to total dust (6-7 mg/m3) and respirable dust (2-3 mg/m3) were found for the shotcreters, shaft drillers, and tunnel-boring machine workers. Shaft drillers and tunnel-boring machine workers also had the highest GM exposures to respirable alpha-quartz (0.3-0.4 mg/m3), which exceeded the Norwegian occupational exposure limit (OEL) of 0.1 mg/m3. Shaft drillers had the highest exposure to oil mists (GM=1.4 mg/m3), which was generated mainly from pneumatic drilling. For other groups, exposure to oil mist from diesel exhaust and spraying of oil onto concrete forms resulted in exposures of 0.1-0.5 mg/m3. Exposure to nitrogen dioxide was similar across all groups (GM=0.4-0.9 ppm), except for shaft drillers and tunnel-boring machine workers, who had lower exposures. High short-term exposures (>10 ppm), however, occurred when workers were passing through the blasting cloud.
authors.affiliation: National Institute of Occupational Health, Oslo, Norway. bba@stami.no
authors.forename: B
authors.initials: B
authors.lastname: Bakke
authors.forename: P
authors.initials: P
authors.lastname: Stewart
authors.forename: B
authors.initials: B
authors.lastname: Ulvestad
authors.forename: W
authors.initials: W
authors.lastname: Eduard
mesh_terms: D004391:Dust; D005740:Gases; D006801:Humans; D016273:Occupational Exposure; D016272:Occupational Health
chemical_list: D004391:Dust; D005740:Gases