Demographic characteristics and exposure assessment of non-welding controls and welders
| Controls (n = 13) | Welders (n = 24) | p value | |
|---|---|---|---|
| *Four controls were monitored during two sampling periods. | |||
| †Eight welders were monitored during two sampling periods and four were monitored over three sampling periods. | |||
| Number (%) of current smokers | 3 (23%) | 10 (42%) | 0.3 |
| Age, years | |||
| Mean (SD) | 41.5 (15.9) | 35.0 (8.0) | 0.2 |
| Range | 19–61 | 22–50 | |
| Years as boilermaker | |||
| Median | 5.0 | 3.0 | 0.1 |
| Range | 1.5–35 | 1–30 | |
| Number of exposure samples | 17* | 40† | |
| Sampling time, hours | |||
| Mean (SD) | 5.1 (1.1) | 5.3 (0.9) | 0.5 |
| PM2.5 concentration, mg/m3 | |||
| Mean (SD) | 0.10 (0.17) | 1.66 (0.91) | <0.001 |
| Median | 0.04 | 1.69 | <0.001 |
| 25th–75th centile | 0.02–0.11 | 0.89–2.44 | |