LAUSR

Abstract The main environmental cause of childhood mortality and morbidity around the world is related to air pollution. This meta-analysis aimed to examine the association between the mortality of infant and children under age of five and exposure to air pollution. PubMed/Medline, Web of Science, and EMBASE databases were searched to recognize studies published from 1992 to 2018. Twenty-seven studies met the inclusion criteria, of which eight studies were conducted in North America, eight in Europe, six in Asia, four in Latin-American and one in Africa. We used the OHAT method (Office of Health Assessment and Translation) for evaluation of the risk of bias. The pooled relative risks of the infant and child under-five mortality were estimated by Random and fixed-effect models. Increases in particulate matter (PM) concentration was related to infant and child under-five mortality (PM2.5 3.4%, per 10 μg/m3 (95% CI: 1.7%–5.4%); PM10 2.5%, per 10 μg/m3 (95% CI: 1.6%–4.3%)). The percent change in the infant and child under-five mortality due to CO, NO2, SO2 and O3 exposure were 3.1% per 1 part per million (95% CI: 1.9–3.9%); 1.7% per 1 parts per billion (95% CI: 0.9–4.8%); 2.0% per 1 parts per billion (95% CI: 1.0–5.0%); and −1.1% per 1 parts per billion (95% CI: −2.6–0.3%), respectively. Conclusively, PM2.5, PM10, CO, NO2, and SO2 were positively and significantly associated with both infant and child under-five mortality. We obtained clear evidence of an association between exposure to particulate and gaseous air pollutants with the infant and child mortality. Registration number in PROSPERO: CRD42019120816.