Table 1. The concentration (μg m−3, GM, GSD, %RSD, and range) of VOCs measured at the 22 sites in WFS and the 16 sites in CDSa.
| MDL (μg m−3) | WFS | CDS | cv% | p1 | p2 | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GM | GSD | %RSD | Range | GM | GSD | %RSD | Range | |||||
| 7/20–22/2005 | ||||||||||||
| MTBE | 0.28 | 5.1 | 1.6 | 92 | 3.0–29 | 5.4 | 1.2 | 19 | 4.3–7.8 | 5.1 | 0.13 | 0.37 |
| Chloroform | 0.05 | 0.23 | 1.1 | 9 | 0.21–0.29 | 0.22 | 1.1 | 8 | 0.20–0.26 | 45 | 0.09 | 0.59 |
| Carbon tetrachloride | 0.06 | 0.57 | 1.0 | 3 | 0.54–0.60 | 0.56 | 1.1 | 5 | 0.51–0.60 | 7.5 | 0.31 | 0.42 |
| Benzene | 0.45 | 1.2 | 1.3 | 28 | 0.79–2.6 | 1.4 | 1.2 | 22 | 1.1–2.2 | 5.4 | 0.13 | 0.98 |
| Toluene | 0.81 | 6.4 | 1.7 | 83 | 3.7–32 | 3.9 | 1.3 | 36 | 3.1–8.2 | 33 | 0.0003 | 0.05 |
| Ethylbenzene | 0.44 | 0.86 | 1.5 | 50 | 0.44–2.5 | 0.63 | 1.2 | 25 | 0.48–1.1 | 25 | 0.002 | 0.03 |
| m/p-Xylene | 1.08 | 2.5 | 1.5 | 60 | 1.2–8.9 | 1.8 | 1.3 | 26 | 1.4–3.1 | 24 | 0.002 | 0.02 |
| o-Xylene | 0.60 | 0.79 | 1.5 | 60 | 0.41–2.9 | 0.60 | 1.3 | 26 | 0.45–1.0 | 20 | 0.002 | 0.05 |
| 8/17–18/2005 | ||||||||||||
| MTBE | 0.28 | 10 | 2.0 | 196 | 4.9–159 | 9.1 | 1.3 | 29 | 6.4–18 | 5.1 | 0.91 | 0.16 |
| Chloroform | 0.05 | 0.14 | 1.1 | 13 | 0.11–0.19 | 0.15 | 1.2 | 16 | 0.13–0.23 | 45 | 0.65 | 0.61 |
| Carbon tetrachloride | 0.06 | 0.45 | 1.0 | 4 | 0.42–0.51 | 0.46 | 1.1 | 5 | 0.41–0.49 | 7.5 | 0.09 | 0.69 |
| Benzene | 0.45 | 0.89 | 1.5 | 54 | 0.50–3.1 | 0.84 | 1.2 | 24 | 0.67–1.4 | 5.4 | 0.94 | 0.06 |
| Toluene | 0.81 | 4.5 | 2.4 | 164 | 1.9–60 | 2.3 | 1.4 | 49 | 1.9–6.8 | 33 | 0.0004 | 0.008 |
| Ethylbenzene | 0.44 | 0.66 | 2.2 | 176 | 0.30–9.2 | 0.41 | 1.2 | 26 | 0.32–0.74 | 25 | 0.002 | 0.05 |
| m/p-Xylene | 1.08 | 1.8 | 2.2 | 175 | 0.81–25 | 1.1 | 1.3 | 29 | 0.85–2.1 | 24 | 0.002 | 0.006 |
| o-Xylene | 0.60 | 0.61 | 2.0 | 134 | 0.29–4.9 | 0.41 | 1.3 | 27 | 0.31–0.73 | 20 | 0.003 | 0.01 |
| 12/20–22/2005 | ||||||||||||
| MTBE | 0.28 | 1.2 | 1.6 | 76 | 0.49–5.7 | 1.4 | 1.3 | 24 | 0.90–1.9 | 5.1 | 0.34 | 1.00 |
| Chloroform | 0.05 | 0.09 | 1.3 | 24 | 0.03–0.15 | 0.08 | 1.0 | 4 | 0.07–0.09 | 45 | 0.005 | 0.07 |
| Carbon Tetrachloride | 0.06 | 0.50 | 1.3 | 16 | 0.19–0.56 | 0.51 | 1.0 | 3 | 0.49–0.55 | 7.5 | 0.03 | 0.11 |
| Benzene | 0.45 | 1.2 | 1.3 | 21 | 0.54–1.8 | 1.2 | 1.1 | 12 | 1.0–1.6 | 5.4 | 0.19 | 0.49 |
| Toluene | 0.81 | 4.1 | 1.9 | 94 | 1.9–23 | 2.2 | 1.2 | 22 | 1.7–3.5 | 33 | 0.001 | 0.007 |
| Ethylbenzene | 0.44 | 0.51 | 1.4 | 36 | 0.32–0.99 | 0.45 | 1.2 | 17 | 0.33–0.62 | 25 | 0.42 | 0.06 |
| m/p-Xylene | 1.08 | 1.4 | 1.4 | 40 | 0.87–3.2 | 1.2 | 1.2 | 21 | 0.88–1.9 | 24 | 0.40 | 0.16 |
| o-Xylene | 0.60 | 0.44 | 1.4 | 39 | 0.24–1.1 | 0.41 | 1.2 | 20 | 0.30–0.62 | 20 | 0.62 | 0.15 |
a
%cv is for the 6 sets of duplicate samples collected from siteW8 and C13; p1 is the p value applied to the concentration comparison between WFS and CDS by Wilcoxon rank sum test, and p2 is for the variability comparison by Wilcoxon rank sum test.