Table 4. Concentrations in Peak Area Units for Gas-Phase VOCs: Geometric Means (95% CIa).
| geometric
mean (95% CI)b |
||||
|---|---|---|---|---|
| compound | TPc | SMc | geo. mean ratio (TP/SM) | p-value |
| acetaldehyde (ppbv·s) | 1 081 242 (928 674, 1 258 876) | 1 078 627 (930 473, 1 250 370) | 1.00 | 0.9505 |
| acetonitrile (ppbv·s) | 231 320 (193 160, 277 019) | 240 574 (203 115, 284 942) | 0.96 | 0.3981 |
| acrylonitrile (ppbv·s) | 18 404 (15 536, 21 803) | 18 689 (15 904, 21 961) | 0.98 | 0.7148 |
| benzene (ppbv·s) | 23 217 (19 813, 27 206) | 23 954 (20 646, 27 791) | 0.97 | 0.3080 |
| 1,3-butadiene (ppbv·s) | 36 533 (31 109, 42 903) | 37 100 (31 844, 43 223) | 0.98 | 0.6652 |
| 2,5-dimethylfuran (ppbv·s) | 14 526 (12 108, 17 428) | 15 528 (13 048, 18 480) | 0.94 | 0.0184* |
| formaldehyde (μg/cartridge) | 0.416 (0.378, 0.458) | 0.380 (0.346, 0.418) | 1.09 | 0.0546 |
a
95% CI = 95% confidence interval.
b
Sample size = 144, using all profiles.
c
TP = true profile; SM = smoothed profile.
*
Significant at p ≤ 0.05 level.