Association between Long-Term Ambient PM2.5 Exposure and under-5 Mortality: A Scoping Review

Abstract

Studies have established a link between exposure to fine particles (PM2.5) and mortality in infants and children. However, few studies have explored the association between post-birth exposure to PM2.5 and under-5 mortality. We conducted a scoping review to identify relevant epidemiological evidence on the association between post-birth ambient PM2.5 exposure and under-5 mortality. We searched PubMed and Web of Science for articles published between 1970 and the end of January 2022 that explicitly linked ambient PM2.5 and under-5 mortality by considering the study area, study design, exposure window, and child age. Information was extracted on the study characteristics, exposure assessment and duration, outcomes, and effect estimates/findings. Ultimately, 13 studies on infant and child mortality were selected. Only four studies measured the effect of post-birth exposure to PM2.5 on under-5 mortality. Only one cohort study mentioned a positive association between post-birth ambient PM2.5 exposure and under-5 mortality. The results of this scoping review highlight the need for extensive research in this field, given that long-term exposure to ambient PM2.5 is a major global health risk and child mortality remains high in some countries.

Culturable Airborne Fungi in Downtown Monterrey (Mexico) and Their Correlation with Air Pollution over a 12-Month Period

“…Fine particles are mostly formed by combustion processes such as motor vehicles, power plants, and wildfires. Ultrafine particles are produced by the nucleation of gas molecules or by fragmentation of larger particles; these PM can penetrate deep inside the lungs or surpass the lung barrier and enter the blood system, respectively, causing a wide range of illnesses; while their effects on human health are complex and not fully understood, several studies have suggested that exposure to the air microbiome and pollution can have adverse impacts on the respiratory system (impaired lung function, inflammation and oxidative stress in the airways and lung tissue, bronchial hyperreactivity and asthma, increased susceptibility to respiratory infections, increased risk of chronic obstructive pulmonary disease and lung cancer) [1,2], cardiovascular system (systemic inflammation, oxidative stress, altered blood pressure, heart rate variability, atherosclerosis promotion, thrombosis, impaired endothelial function and vascular reactivity, increased cardiac arrhythmias, ischemia, risk of stroke and myocardial infarction) [3][4][5][6], immune system (affecting the production and function of cytokines, chemokines, antibodies, and immune cells, influencing the activation and differentiation of T cells and B cells, enhancing or suppressing allergic responses and autoimmune diseases, altering the susceptibility to infectious agents and vaccines) [7], gut microbiota (dysbiosis, increasing intestinal permeability and inflammation, altering the production of short-chain fatty acids and other metabolites that regulate host metabolism and immunity) [8,9], a correlation with autism and brain inflammation diseases [10,11], and a general increase in risk of mortality [12,13].…”