## 3 Results
However, Methylene Chloride; Ethylbenzene; o-Xylene; m-Xylene; p-Xylene; Stylene; 1-Methyl Ethyl Benzene; Tert-Butyl Benzene; 1, 3, 5-Trimethyl Benzene; 1-Methyl Propyle Benzene; and 1, 4-Dichloro Benzene were found both in a sorbent tube and in the SPME samples. Table 3 presents only the chemicals detected in charcoal tubes, and the chemical concentrations in the percentage of occupational exposure limits (OEL) if there is one. The quantification of SPMEs in the field samples was not performed because of the required assumptions on how much air came in contact with the needle. The analytes absorbed on the needle can be quantified, and quantitative measurements are frequently performed on a water sample [40; 41]. Some investigators have included air pumps to fix the amount of air that the needle's sorbent material contacts [42]. While absolute quantitation of VOCs and SVOCs in passive air samples is difficult at best, the relative concentration measurement of these analytes in the air is certainly possible. For example, if a needle is deployed for 8 h on day one and then another needle is deployed for 8 h in the same location on day two, it is reasonable to assume that, if the peak area on a GC or GC/MS chromatogram doubles in size on day 2, it is likely that the air concentration also doubled on day 2. The assumptions would be that all of the same diffusion conditions were equal on both days and that errors in the relative quantitation would be related to a deviance in those assumptions (e.g., a doubling of wind speed). \begin{table} \begin{tabular}{c c c c} \hline \hline
**Activities** & **Chemicals** & **Concentration** & **OEL** \\ \hline Land preparation (\(n=30\)) & Methylene Chloride & \(\leq\)10\% at OEL & PEL = 25 ppm [34] \\  & 1, 1, 1 Trichlor Ethane & TWA = 350 ppm a \\  & Benzene & TWA = 1 ppm [35] \\  & Ethylbenzene & TWA = 100 ppm a \\  & o-Xylene & TWA = 100 ppm a \\  & m-Xylene & TWA = 100 ppm a \\  & p-Xylene & TWA = 100 ppm a \\  & Styrene & TWA = 50 ppm a \\  & 1-Methyl Ethyl Benzene & TWA = 50 ppm [36] \\  & 1, 3, 5-Trimethyl Benzene & TWA = 25 ppm [37] \\  & 1, 4-Dichloro Benzene & TWA = 75 ppm a \\  & Naphthalene & \(\leq\)50\% at OEL & TWA = 10 ppm [38] \\  & Ter-Butyl Benzene & No occupational exposure limits a \\  & 1-Methyl Propyle Benzene & & \\  & 1, 2, 3 Trichlor Benzene & & \\  & Methylene Chloride & \(\leq\)10\% at OEL & PEL = 25 ppm [34] \\  & 1, 1, 1 Trichlor Ethane & TWA = 350 ppm a \\  & Ethylbenzene & TWA = 100 ppm a \\  & o-Xylene & TWA = 100 ppm a \\  & m-Xylene & TWA = 100 ppm a \\  & p-Xylene & TWA = 100 ppm a \\  & Styrene & TWA = 50 ppm a \\  & 1-Methyl Ethyl Benzene & TWA = 50 ppm [36] \\  & 1, 3, 5-Trimethyl Benzene & TWA = 25 ppm [37] \\  & Naphthalene & \(\leq\)50\% at OEL & TWA = 10 ppm a \\  & 1-Methyl Ethyl Benzene & TWA = 50 ppm [36] \\  & 1, 3, 5-Trimethyl Benzene & TWA = 25 ppm [37] \\  & Naphthalene & \(\leq\)50\% at OEL & TWA = 10 ppm [38] \\  & 1, 2, 3 Trichlor Benzene & No occupational exposure limits a \\ \hline \hline \end{tabular}  Note: OEL: occupational exposure limit, TWA: time-weighted  
Given that the activated carbon badge was deployed on the same day for exactly the same amount of time, it is logical to assume that both samplers encountered the same air volume from which to sample. While absolute quantitation cannot be assumed for the SPME data, a direct comparison of that integrated peak area on a compound-by-compound basis provides the relative difference in sensitivities between SPME and the activated carbon badges. Table 4 describes the differences in the integrated peak areas for the compounds detected by SPME, so relative sensitivities can be compared. The data demonstrate that many of the compounds were present only on the SPME fiber. This suggests a greater applicability/versatility of the fiber from many of the VOCs and SVOCs measured. For this reason, our lab [43] and others [44; 45] have previously used SPME to detect mold-related VOCs (MVOCs). The SPME fiber appears to generally be more sensitive as well.