Objective To investigate the acute effect of PM10 on the respiratory symptoms of students in Taiyuan, China.
Methods Surveillance data about respiratory symptom of the students were collected in all primary/secondary schools and kindergarten within the 1km of the national air pollution surveillance sites in Taiyuan from 2017 to 2019, and daily concentrations of air pollutants were matched according to the date of disease onset and the corresponding surveillance site for each school. A time-stratified case-crossover study was conducted to assess the lag effect and cumulative effect of PM10 on the appearance of symptoms of respiratory system in students by a conditional logistic regression model.
Results The median of daily concentration of PM10 was 122 μg/m3 in Taiyuan during the study period, with number of days exceeding national secondary ambient air quality standard(150 μg/m3) being 307(28%). The effects of PM10 at lag0-lag1, lag3-lag7, and lag01-lag07 days had a statistical significance on the risk assessment of symptoms(P < 0.05), with the strongest effect within 4 days after PM10 exposure. For every 10 μg/m3 increase of PM10, the incidence rate of symptoms of respiratory system was increased by 1.4%95% confidence internal(CI): 1.1%, 1.8%. The results by grade showed that air pollution had the greatest impact on kindergarten students, followed by lower primary school(grades 1 to 3), middle school(middle and high school), and upper primary school(grades 4 to 6). For every 10 μg/m3 increase of PM10, the incidence of respiratory symptoms was increased by 2.0%(95% CI: 1.6%, 2.5%), 1.5%(95% CI: 0.3%, 2.7%), 1.4%(95% CI: 0.7%, 2.1%) and 0.8%(95% CI: 0.2%, 1.4%), respectively.
Conclusion PM10 has an acute health effect on respiratory symptoms in students in Taiyuan, and the impact on primary and secondary school students and kindergarten students is different. The schools should arrange type and time of outdoor activities reasonably for students.
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