Table 1

8 Hour time weighted average exposures and cumulative exposures in heavy construction workers stratified by job group

Agent		Units		OEL		Tunnel workers
						Drillers (n^1-151=52)					Shotcreters (n^1-151=14)		Outdoor workers (n^1-151=20)		White collar employees^1-152
						n^1-150	Mean				SD	n^1-150	Mean	SD	n^1-150	Mean	SD	Mean
Total dust	mg/m³	10	113	3.4	3.8		61	13.6	9.1	35	1.2	0.78		0.34
Respirable dust	mg/m³	5	117	1.2	0.81		69	3.6	1.9	40	0.3	0.19		0.12
Cumulative exposure to respirable dust^1-160	mg.y/m³			9.6	0.2			25.4	0.9		2.1	0.1		0.9
α-Quartz	mg/m³	0.1	113	0.044	0.06		45	0.019	0.016	40	0.003	0.003		0.004
Cumulative exposure to α-quartz^1-160	mg.y/m³			0.35	0.01			0.13	0.01		0.029	0.001		0.023
Oil mist	mg/m³	1	79	0.35	0.21		23	0.55	0.59	16	0.18	0.23		0.04
Nitrogen dioxide	ppm	2^1-153	39	0.78	0.69		15	0.6	0.5		^1-154			0.08

↵1-150 Number of measurements.
↵1-151 Number of workers participating in measurements.
↵1-152 Estimate.
↵1-153 Ceiling value.
↵1-154 Non-detectable, assumed to be ambient air concentrations, 10–20 ppb (Norwegian Institute for Air Research, Kjeller, Norway).
↵1-160 Adjusted for sick leaves and other longer periods of absence.
OEL=Norwegian occupational exposure limits.