The Microsuspension Modification

Given the very small amounts of material found in atmospheric samples, improvements in the Ames assay 

TABLE 10.17 Comparison of Specific Mutagenic Activities of Several Standard Nitroarenes Determined on Strain TA98 (— S9) Using the Salmonella typhimuriurn Assay with and without the Kado Microsuspension Modification -  

This modification has been applied in a variety of studies, including the mutagenic activity of fine ambient air particles as a function of particle size (Kado et 

TABLE 10.18 Direct Mutagenic Activities, TA98 ( —S9), in the Salmonella typhimuriurn Assay (Microsuspension Preincubation) of Standard Samples of 14 Methylnitronaphthalene Isomers  

Until the early to mid-1980s, research on the mutagenicity of respirable POM focused almost exclusively on the particulate phase. Another aspect of tropospheric chemistry with significant health implications is the application of the Ames bacterial assay (with or without the microsuspension modification) to the detection and identification of mutagenic vapor-phase PAHs and PACs. For example, Harger and co-workers (1992) reported that the mutagenicities of concurrently collected samples of vapor-phase and particle-phase organics in southern California (Claremont, California) ambient air were comparable. 

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Some modifications to the microsuspension process have been developed such as a seeded process (12) and an extension to this where an emulsion polymer latex, particle size sO.lpm, is added to the seed latex and monomer at the beginning of the polymerisation (13). In the latter process it is claimed that by... 

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