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<br />Sample collection was performed as follows: The sample bag <br />was emptied. One end of the teflon sample line was connected to the <br />bag's valve and the other end inserted into the effluent stream. The <br />bag was filled, emptied, and filled again. The valve was closed, sample <br />line disconnected, and the bag number and collection time recorded on <br />the data sheet. Upon completion of the on-site testing, the sample bags <br />were returned to ~lliT for analyses. <br /> <br />A panel of at least six experienced members was used to evaluate <br />the samples. Each of the members had been previously screened for olfactory <br />perception using the vanillanjmethyl salicylate "triangle" test. Each <br />panel member was assigned a syringe which he used for the entire series <br />of tests unless it became contaminated. Contaminated syringes were re- <br />placed with freshly cleaned units. <br /> <br />The analyses took place in a temperature controlled room in <br />which the room air was continuously recirculated ~hrough activated carbon <br />filters. Various levels of dilution of the collected samples were prepared <br />and presented to the members of the odor panel. The panel members smelled <br />the samples and merely recorded whether or not they detected an odor. <br />After the sample was smelled, the panel member flushed his syringe with <br />room air until he was satisfied that no odor remained. <br /> <br />At the completion of the panel presentation, the responses were <br />collected, tabulated, and reviewed for any individual inconsistencies. <br />The data points (dilution, response percent positive) were then plotted <br />on log-probability graph paper and the best (least square) straight line <br />drawn. The dilution corresponding to 50 percent positive response was <br />taken to be the odor concentration expressed in odor units per cubic foot. <br /> <br />7 <br />