Objective: To investigate the effects of ambient air pollution on the school age children s diseases, symptoms and school absence, and to provide a reference for preventing the harmful effect of air pollution on students. Methods: Health questionnaires surveys were conducted among 792 students of the fourth grade in a primary school in Hangzhou, and the incidence of diseases and symptoms were continuously monitored every day during the winter of 2014-2017. The generalized additive model based on Poisson regression was used to analyze the health effects caused by single pollution. The multivariate Logistic regression model was used to analyze the comprehensive effects of family, living environment and air pollution on student health. Results: Totally 415 students(52.4%) had a history of diseases and 265 students(33.5%) had a history of allergy. During the investigation, the average concentrations of PM 2.5 , PM 10 , SO 2 and NO 2 were (81.0±2.8) (122.2±3.9) (17.9±0.6) and (68.9±1.4)μg/m 3. Strongest associations were found for lag 3 day of exposure among PM 2.5 , PM 10 and NO 2 on illness and absence. Increases of 10 μg/m 3 in PM 2.5 , PM 10 and NO 2 were associated with 1.02(95% CI =1.01-1.02), 1.04(95% CI =1.03-1.06) and 1.03(95% CI =1.02- 1.04 ) increases in daily illness rates. SO 2 lag for 5 days had the most significant effect on students health. Father s education was the protective factor for illness ( OR =0.83) and symptoms( OR =0.84 ). The risk factors for symptoms included furniture replacement within one year( OR =1.78), pet feeding( OR =1.94), respiratory infections within one year( OR =1.82), allergies rhinitis( OR =2.24), family history with coronary heart disease/hypertension( OR =1.46), indoor activity time ( OR =1.02) and atmospheric PM 10 concentration( OR =1.09)( P <0.05). Conclusion The increase of air pollution concentration has an impact on the illness, symptoms and absence from school, and there is a lag effect. Father s education is a protective factor for the health of students. Indoor pollution and outdoor air pollution can lead to the occurrence of illness and symptoms.

A total of 1 685 school-age children selected from Hangzhou received lung function testing to evaluate the short-term effects of air pollution on their lung function. The results showed that in every 10 μg/m³ increase of average concentration of PM_2.5 and PM₁₀ on the day of the test and the day before the test,peak expiratory flow (PEF) decreased 0.039 (95%CI: 0.012-0.067) L/s and 0.031 (95% CI:0.011-0.051) L/s,respectively. When the average concentration of SO₂ increased 10 μg/m³ on the day of test and the day prior to the test, PEF and 75% of the forced vital capacity that has not been exhaled (MEF₇₅) decreased 0.437 (95%CI: 0.217-0.658) L/s and 0.396 (95%CI: 0.180-0.613) L/s. After being adjusted for NO₂,with every 10 μg/m³ increase of average concentration of PM_2.5 and PM₁₀ on the day of the test and the day before the test,PEF and MEF₇₅ decreased 0.056 (95%CI: 0.028-0.085), 0.053(95%CI: 0.027-0.081) and 0.047 (95%CI: 0.026-0.068) L/s,0.044 (95%CI: 0.023-0.065) L/s on the day before the test, respectively. The results indicate that air pollution have short-term and lag effects on lung function of school-age children in Hangzhou.