Objective      To determine the effect of inhalable particulate matter (PM) on respiratory system diseases in children living in Chongqing region in order to provide scientific basis for improving air quality and protecting children’s health.       Methods      All pupils at Grade 3-4 from 3 different primarily schools which respectively located in heavy polluted area

relatively less polluted area and cleaning area in Chongqing were subjected by stratified cluster sampling. Based on our exclusion criteria

317 male and 318 female students were finally enrolled to be respondents to measure pulmonary function and reply questionnaire. Then PM10 and PM2.5 data were collected from these areas respectively at the same time.       Results       The concentrations of inhalable PM were higher in winter and spring than in summer and fall. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were higher in the pupils whose school located in cleaning area than those from the other 2 areas (P0.05)

but there were no obvious rules in the values of maximal mid-expiratory flow curve (MMEF)

V75 and V50 among the 3 groups of pupils. Meanwhile

the incidences of cough

cold with cough

expectoration

cold with expectoration

cough with expectoration and bronchitis were obviously higher in the pupils from heavy polluted area than those from cleaning area (P0.05).       Conclusion        Inhalable PM might be a risk factor for respiratory system diseases in children.