Adverse health outcomes in early childhood (birth to 5 years) and ambient air pollutant exposures: a systematic review

Air pollution is a significant health threat around the world. Young children are a more vulnerable population. Environmental Protection Agency (EPA) and World Health Organizations (WHO) guidelines may not adequately protect them. Given children’s rapid growth, it is important to review studies, consider the weight of evidence, and identify knowledge gaps. Our purpose was to conduct a systematic literature review of epidemiological studies of adverse health outcomes not previously considered; specifically, we reviewed evidence for traffic-related air pollution (TRAP) CO, NO 2 , SO 2 , O 3 , PM 10 , and PM 2.5 in children ≤ 5 years in age, with special attention to adverse effects occurring within current air pollutant guidelines. Data sources are electronic search of PubMed, MEDLINE, and Google Scholar. Articles on air pollutants and additional health outcomes in children (0–5 years), between Jan. 1997 and Dec. 2018. Search included terms such as “air pollution, children, and adverse effects”. Fifty-two studies met the inclusion criteria. Seven (7) health outcome categories were identified: respiratory diseases; developmental disorders; allergies, eczema, and allergic rhinitis; ear infections; cancer; obesity; and others, with greatest associations for respiratory and developmental disorders. Strongest findings were for NO 2 , O 3 , PM 10 , and PM 2.5, and most health effects reviewed occurred within WHO limits. Our findings are pertinent for health professionals, researchers, government officials, and others to collaboratively support policy efforts toward exposure reductions for pregnant women and children to prevent acute and chronic diseases. This is critical for building a culture of health and ensuring health equity for vulnerable populations.