Abstract: Objective To describe the type and variation of outdoor air pollution in Panjin city of Liaoning province and to explore the effect of the pollution on respiratory system in pupils.Methods Industrial,traffic and clean areas in Panjin city were identified based on air pollution monitoring data between 2010 and 2014.Totally 7 primary schools within one kilometer in straight-line distance from a monitoring sampling site for air pollution (2 in industrial,one in traffic and 2 in clean areas)were chosen as survey sites and 1 853 pupils recruited from the 7 schools were surveyed with the Respiratory Disease Questionnaire recommended by American Thoracic Society in December 2014.Results The concentrations of particulate matter less than 10 μm in aerodynamic diameter (PM10),sulfur dioxide (SO₂),and nitrogen dioxide in ambient air of industrial and traffic areas were all significantly higher than those in clean areas (P<0.01 for all).Significant positive correlations were observed between levels of ambient air pollutants and reported incidences of persistent cough,persistent phlegm and wheeze among the pupils (all P<0.05).The pupils living in houses less than 5 meters away from a main traffic road reported higher incidences of respiratory symptoms and persistent cough,with the odds ratios (95% confidence intervals) of 2.33 (1.18-4.61) and 4.49 (2.18-9.27),respectively.Conclusion Traffic and coal-burning in winter are main air pollution sources in urban areas of northern China and ambient air pollution can aggravate incidence of respiratory diseases among pupils with susceptible factors.