A comprehensive evaluation of the association between ambient air pollution and adverse health outcomes of major organ systems: a systematic review with a worldwide approach

Ambient air pollution is nowadays one of the most crucial contributors to deteriorating health status worldwide. The components of air pollution include PM₂.₅ and PM₁₀, NO₂, SO₂, CO, O₃, and organic compounds. They are attributed to several health outcomes, for instance, cardiovascular diseases (CVD), respiratory diseases, birth outcomes, neurologic diseases, and psychiatric diseases. The objective of this study is to evaluate the association between different ambient air pollutants and the above-mentioned health outcomes. In this systematic review, a total of 76 articles was ultimately selected from 2653 articles, through multiple screening steps by the aid of a set of exclusion criteria as non-English articles, indoor air pollution assessment, work-related, occupational and home-attributed pollution, animal studies, tobacco smoking effects, letters to editors, commentaries, animal experiments, reviews, case reports and case series, out of 19,862 published articles through a systematic search in PubMed, Web of Science, and Scopus. Then, the associations between air pollution and different health outcomes were measured as relative risks and odds ratios. The association between air pollutants, PM₂.₅ and PM₁₀, NO₂, SO₂, CO, O₃, and VOC with major organ systems health was investigated through the gathered studies. Relative risks and/or odds ratios attributed to each air pollutant/outcome were ultimately reported. In this study, a thorough and comprehensive discussion of all aspects of the contribution of ambient air pollutants in health outcomes was proposed. To our knowledge up to now, there is no such comprehensive outlook on this issue. Growing concerns in concert with air pollution-induced health risks impose a great danger on the life of billions of people worldwide. Should we propose ideas and schemes to reduce ambient air pollutant, there will be dramatic reductions in the prevalence and occurrence of health-threatening conditions.