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" Source: Adapted from Hannigan et al. (1998).

6 Concentrations of each PAH/PAC quantified in extracts of "whole composite samples" and of extracts of various mutagenic subfractions. The latter values are generally lower because of losses during separations and extractions. The annual average airborne fine particle equivalent organic carbon (EOC) concentration for this Los Angeles basinwide 1993 composite sample was 8.89 ¡jlg/m3 of EOC. The latter is defined as "organic carbon on the atmospheric filter sample as determined by thermal evolution and combustion analysis prior to sample extraction."

' Single-compound potencies in the standard 12-mL hlAlv2 assay determined using data of Durant et al. (1996). Units are induced mutant fraction X 10''/ng of PAH or PAC tested. ND, not detected but included for reference.

''All PAHs and PACs listed in this modified table were identified and quantified at the "positive" confidence level.

' Compound measured only in subfractions.

' Compound also measured in small amounts in another subfraction; for clarity, not included here.

s 2-Nitropyrene is not mutagenic in this human cell assay. Concentrations of this atmospheric reaction product are included for comparison to concentrations of 1-nitropyrene (are predominantly from primary emissions) in this composite ambient sample (see Section F).

h Single-compound potencies relative to BaP taken as 1.00. Note: Some of these relative human cell potency equivalence factors for certain PAHs and PACs seem to differ significantly from those reported by Durant et al. (1996); e.g., compare their data (e.g., see Table 10.13) with those reported in the Hannigan et al. (1998) article.

' See Table 10.24 for concentrations of these PAHs in various urban atmospheres.

TABLE 10.26 Concentrations, Potencies, and Percentage Contributions of Selected PAHs and PACs Tested in the hlAlv2 Human Cell Assay'' and Positively Identified in the Bioassay-Directed Chemical Analysis of a Composite "Whole Sample" Made Up of Fine Ambient Aerosols Collected at Four Urban Sites in the Los Angeles Air Basina'c

Contributions to mutagenic potency of "whole" sample 150 ± 31 IMF (X106) mgofEOC

Concentration" in

Mutagenic

Concentration-weighted

Percentage of "whole" sample

Contributions to mutagenic potency of "whole" sample 150 ± 31 IMF (X106) mgofEOC

Concentration" in

Mutagenic

Concentration-weighted

Percentage of "whole" sample

Compound

Formula

"whole" sample

potency6

potency''

potency

PAHs

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