Objective To explore the influence of PM_2.5 on short-term acute symptoms among children.

Methods A panel study was performed in December 2016, and a questionnaire survey was performed for acute health symptoms among 32 children for 28 consecutive days. The multilevel logistic regression analysis and distributed lag non-linear model (DLNM) were used to investigate the association between PM_2.5 and acute health symptoms in children.

Results From December 1 to 28 in 2016, the daily mean mass concentration of PM_2.5 was (122.86±98.38) μg/m³ in Beijing. During this 28-day period, the children were followed up for 896 person-times, and the total frequency of acute health symptoms was 485 person-times, among which cough had the highest frequency of 141 person-times (15.74%). Multilevel logistic regression integrated with DLNM analysis showed that exposure to PM_2.5 for Lag3~Lag6 was significantly associated with children symptoms of wheezing, cough, headache and eye pain in children. For every 10 μg/m³ increase in PM_2.5 (Lag5), the risk of wheezing was increased by 0.20% (95% CI: 0.14%-0.26%), and for every 10 μg/m³ increase in PM_2.5 (Lag6), the risks of cough, headache and eye pain were increased by 0.50% (95% CI: 0.13%-0.87%), 0.18% (95% CI: 0.06%-0.30%) and 0.22% (95% CI: 0.09%-0.35%), respectively. The daily mean mass concentration of PM_2.5 had a cumulative lag effect on wheezing in children, and the cumulative lag effect lasted for 3 days (Lag6-Lag8); for every 10 μg/m³ increase in PM_2.5, the maximum cumulative lag effect was increased by 0.80% (95% CI: 0.18%-1.42%).

Conclusion PM_2.5 would mainly increase wheezing risk of children, and the influence of PM_2.5 in Beijing on acute health symptoms among children might lag for one week.