Total dust mg·m−3 | Respirable dust mg·m−3 | ‐quartz mg·m−3 | Nitrogen dioxide /ppm | |||||
n | n | n | n | |||||
Underground | 27 | 5.40±1.42 | 30 | 1.61±1.43 | 30 | 0.087±1.61 | 30 | 0.70±0.51 |
Outdoor | 35 | 1.0±1.78 | 40 | 0.21±1.69 | 40 | 0.003±1.82 | 5 | nd |
Data presented as geometric mean±sd
Norwegian hygienic standards (HS)=10 mg·m3
HS=5.0 mg·m3
HS=0.1 mg·m3
HS=2.0 parts per million (ceiling value)
p<0.001
nd: not detectable.