Abstract: ObjectiveTo approach the effects of air pollution on respiratory tract flora in order to provide scientific basis for improving existent environment and preventing diseases.MethodsChildren aged 6～8 years from severe and mild pollution areas without occupational exposure and administering antibiotics in the latest three months were selected and determined qualitatively for their oral-pharynx flora.ResultsOral-pharynx flora were greatly affected by external environment.The density of children's oralpharyngeus flora was markedly higher in the severe area than that in the mild one(P<0.01).The ratio of aerobes and anaerobes was obviously increased(P<0.01),and the detecting rate of pneumoocci was higher,However it was lower in α-streptococci (P<0.05).ConclusionAir pollution markedly influenced the field planting of flora in respiratory tract.It was an imponant factor for imbalance of microecosystem and the increasing incidence of reapiratory diseases.