Table 1.

Study population characteristics

Nonsmokers (n = 10)Current smokers (n = 10)P*
Age (y)
    Mean ± SD46.5 ± 10.844.3 ± 13.60.7
    Range18 - 5523 - 59
Years as boilermaker
    Mean ± SD23.5 ± 9.420.0 ± 16.00.6
    Range1 - 340.04 - 40
Urinary cotinine concentration (μg/g creatinine)
    Mean ± SD13 ± 6555 ± 6650.03
    Median13285<0.001
    Range5 - 2314 - 1,723
Occupational PM2.5 8-hour time-weighted average (mg/m3)
    No. samples1317
    Mean ± SD0.81 ± 0.860.66 ± 0.640.6
    Median0.360.460.7
    Range0.10 - 3.140.11 - 2.28
  • * Two-sample t tests and Wilcoxon rank-sum tests with exact Ps used to compare characteristics in nonsmokers and smokers.