The relationship between particulate matter and lung function of children: A systematic review and meta-analysis

There have been many studies on the relationship between fine particulate matter (PM2.5) and lung function. However, the impact of short-term or long-term PM2.5 exposures on lung function in children is still inconsistent globally, and the reasons for the inconsistency of the research results are not clear. Therefore, we searched the PubMed, Embase and Web of Science databases up to May 2022, and a total of 653 studies about PM2.5 exposures on children's lung function were identified. Random effects meta-analysis was used to estimate the combined effects of the 25 articles included. PM2.5 concentrations in short-term exposure studies mainly come from individual and site monitoring. And for every 10 μg/m3 increase, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF) decreased by 21.39 ml (95% CI: 13.87, 28.92), 25.66 ml (95% CI: 14.85, 36.47) and 1.76 L/min (95% CI: 1.04, 2.49), respectively. The effect of PM2.5 on lung function has a lag effect. For every 10 μg/m3 increase in the 1-day moving average PM2.5 concentration, FEV1, FVC and PEF decreased by 14.81 ml, 15.40 ml and 1.18 L/min, respectively. PM2.5 concentrations in long-term exposure studies mainly obtained via ground monitoring stations. And for every 10 μg/m3 increase, FEV1, FVC and PEF decreased by 61.00 ml (95% CI: 25.80, 96.21), 54.47 ml (95% CI: 7.29, 101.64) and 10.02 L/min (95% CI: 7.07, 12.98), respectively. The sex, body mass index (BMI), relative humidity (RH), temperature (Temp) and the average PM2.5 exposure level modify the relationship between short-term PM2.5 exposure and lung function. Our study provides further scientific evidence for the deleterious effects of PM2.5 exposures on children's lung function, suggesting that exposure to PM2.5 is detrimental to children's respiratory health. Appropriate protective measures should be taken to reduce the adverse impact of air pollution on children's health.