Abstract: Objective To understand the mimune function and the effect of air pollution in school age children in Taiyuan city of Shanxi province and to provide references for air pollution control.Methods A total of 142 pupils aged 11-14 years in different traffic pollution areas were selected and investigated with a questionnaire.Cell immune functions (CD3⁺,CD4⁺,CD8⁺,CD4⁺/CD8⁺)were detected by flow cytometry.Humoral mimune functions(IgG,IgA,IgM)were determined with immunological turbidimetry.The acticity of saliva bacteriolytic enzyme was detected with turbidmietry.The mimune related cells(white blood cell,lymphocyte,red blood cell,platelet)were analyzed by automatic biochemical analyzer.Results Based on multiple linear regression analysis,cell mimune indexes of CD3⁺,CD4⁺,CD4⁺/CD8⁺ were correlated with traffic pollution with the regression coeffic ients of 7.80,7.566,0.381,respectively(P<0.01).CD3⁺ was related to riding bicycle ormotorcycle on the way to school and using air-conditioner and electronic heating in winter with the regression coeffic ients of 6.955 and 6.238(P<0.05).Humoral immune index of IgG was correlated with ways of heating in winter with regression coefficients of 1.172 or 1.743(P<0.05).The factor correlated with IgA was housing type with a regression coefficient of -0.301(P<0.05).The influencing factor of the saliva bacteriolytic enzyme activity was traffic pollution with a regression coefficient of 63.945(P<0.01).White blood cells,lymphocytes,red blood cells,and platelets were correlated with traffic pollution with the regression coefficients of -0.513,-0.267-0.122,-34.855,respectively (P<0.05).Conclusion The mimune function of school age children correlates with traffic pollution,way of going to school,type of housing,and heating way in winter.The effect of traffic pollution is most significant.