The global burden of pediatric respiratory infections attributable to long-term exposure to fine particulate matters.

Respiratory tract infection (RTI) is the leading cause of child mortality in some low- and middle-income countries, which has been linked to ambient fine particulate matter (PM). However, the overall burden of PM-attributed RTIs is unclear, due to the unavailable exposure-response function for long-term exposure. By performing a systematic review of the literature in the MEDLINE, Embase, and Web of Science databases, we conducted a meta-analysis to calculate pooled effect estimates of the association between long-term PM exposure and the prevalence of RTI and its subtypes among children, and further developed an exposure-response function, with a meta-regression-based method. Subsequently, the function was used to assess the global burden of pediatric PM-related RTIs from 2000 to 2019. A meta-analysis of 21 studies on PM exposure and RTIs [15 specifically examining lower respiratory infections (LRIs)] found that each 10 μg/m annual PM increase was associated with 6 % (95 % CI: 4-7) and 8 % (95 % CI: 5-11) higher prevalence of RTIs and LRIs, respectively. By applying the conducted function, we found PM-attributed LRIs decreased from 0.69 million (95 % CI: 0.38-0.86) in 2000 to 0.57 million (95 % CI: 0.28-0.70) in 2019, while RTIs increased from 12.77 million (95 % CI: 10.51-14.42) to 15.37 million (95 % CI: 12.75-17.08) during this period. Long-term exposure to PM increases the risk of respiratory infections among children. Assessment of the spatiotemporal distribution of the attributable disease burden showed that in tropical low- and middle-income countries, decreasing air pollution would safeguard the health of children.