Abstract: To explore the genetic toxicity on different components of PM_2.5 in Huinan and Pudong during winter and summer, the SOS chromotest is used to detect the genetic toxicity of the total particulate, the organic extract and the water-soluble component. Results shows that tests of the genetic toxicity on the total particulate in Huinan are positive at the highest concentration of 2 mg·mL^-1 both in winter and summer, also are positive in Pudong respectively at the concentration of 1 mg·mL^-1 in winter and at the highest concentration of 2 mg·mL^-1 in summer. Tests of the genetic toxicity at two stations both in winter and summer on the water-soluble component are positive at the highest concentration of 2 mg·mL^-1and negative on the the organic extract in the range of 0.000 2 mg·mL^-1and 2 mg·mL^-1. To further compare the genetic toxicity of the PM_2.5 in Huinan and Pudong during winter and summer when exposed to the same volume air, the genetic toxicity of the different components are expressed as the content of the 4-nitroquinoline oxide (4-NQO) per cubic meter of air. Results indicat that the genetic toxicity of the fine particulate matter in Shanghai Puding and Huinan is seasonal and higher in summer than in winter. Furthermore the genotoxic component and the concentration of the total particulate and the water-soluble during winter and summer may be different. It, combined with the result of existing studies that pollutants concentration or components of fine particulate matter were generally higher in winter than in summer at multiple sites in Shanghai, is speculated that the genetic toxicity of atmospheric particulates in every part of Shanghai has similar seasonal change rule. The genotoxic effect of the organic extract is not significant. The main source of the genetic toxicity in the fine particulate matter may be the water-soluble component. The atmospheric pollution at Pudong stationwas continuously serious and equivalent to Huinan stationon the pollution level and the genetic toxicity in same seasons. It is speculated that the genotoxic chemical compositions of atmospheric particulate matter at Pudong station and Huinan station are similar.

Key words: Shanghai, SOS chromotest, particulate matter, genotoxicity