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Show Page 2 DESCRIPTION OF THB DATA BASE The final data base presented with this paper is contained in the figures and tables which are described below. The abbreviations used in the data base are listed and defined at the end of this section. figure 1: Figure 1 describes the molecular structures of dioxins and furans. It also lists the total number of possible isomers in each of the dioxin and furan homologues as well as the number of those isomers which have chlorine atoms substituted in the 2,3,7,8 positions. Table lA: Table lA presents the normalized emissions of dioxins and furans which were developed from the published results of testing flue gas samples from 19 different incinerators in Europe, Japan, Canada and the United States. For presentation in this table, the published test data were adjusted to this normalized basis: • The emissions are for the tetra through the octachlorinated dioxins (D4-a) and furans (F4-a). • The dioxin plus furan emissions (D + F) are the sum of the D4 - a and the F4-a emissions. • The normalized emissions are defined as micrograms of emissions per normal cubic meter (ug/Nm3) of dry flue gas at 0 °C and adjusted to 12 %v CO2 in the dry flue gas. • The normalized emissions are presented first as adjusted for spike recovery (ASR) and then as unadjusted for spike recovery (USR). The data for the first 16 incinerators listed in Table lA were taken from Beychok (1987), who explains why normalization was needed and how it was done. The details of how the reported data for the last 3 in-cinerators in Table lA were normalized are included in the documenting appendix. The 19 emission values in Table lA are too small a data set from which to derive any correlations between D + F emissions and incinerator age or design, fuel type or other parameters .... and no such correlations are apparent. Table lB and Figure 2: Table IB takes the D + F emission values (adjusted for spike recovery) from Table lA, groups them into intervals of 1 ug/Nm3, and lists the cumulative percent frequency of occurrence for each interval mid- range value. Thus, Table IB provides a distribution of the D + F emission values which is plotted on normal probability graph paper in Figure 2. Figure 2 can be used to determine the percentage of the D + F emission values listed in Table lA that is encompassed by any selected emission value. For example, a selected D + F emission value of 8 ug/Nm3 would encompass 81 percent of the 19 values listed in Table lAo When making an assessment of the health risks associated with the dioxin and furan emissions from refuse incineration, Figure 2 provides an insight as to the credibility of the emission values used in the risk assessment. |