Air Pollution and Human Health: A Scoping Review

<title>Abstract</title> <p> Air pollution is an important environmental health concern because exposure to ambient air pollutants has been associated with adverse health effects, particularly among susceptible populations such as children, older adults and individuals with underlying health conditions. This scoping review aimed to map and summarise the available evidence on the association between ambient air pollution and human health. A literature search was conducted in April 2021 using PubMed and ScienceDirect to identify relevant studies published in English between 2016 and 2021. Quantitative observational and population-based studies examining human health outcomes in relation to ambient air pollution exposure were considered for inclusion. A total of 1,145 potentially relevant records were identified through database searching. Following screening, duplicate removal and assessment against the eligibility criteria, 71 unique studies were included in the final review. Information was charted according to pollutant, health effect, study location, study period and study design. The included studies investigated major ambient air pollutants, particularly particulate matter with an aerodynamic diameter of less than 10 µm (PM ₁₀ ), particulate matter with an aerodynamic diameter of less than 2.5 µm (PM _2.5 ), nitrogen dioxide (NO ₂ ), sulphur dioxide (SO ₂ ), carbon monoxide (CO) and ozone (O ₃ ), together with several other ambient pollution indicators. Respiratory and cardiovascular outcomes were the most frequently investigated health effects, including asthma, respiratory infections, cardiovascular events, emergency department visits, hospital admissions and outpatient visits. Other reported outcomes included ulcerative colitis, mental disorders, migraine, diabetes-related outcomes, amyotrophic lateral sclerosis, changes in brain structure, acute otitis media and peptic ulcer bleeding. Overall, the evidence mapped in this review indicates that ambient air pollution has been associated with a broad range of adverse health outcomes, although the reported associations varied according to pollutant, population, exposure period, health outcome and study design. These findings provide an overview of the scope of existing evidence and highlight the importance of continued air pollution prevention and control measures to protect population health. </p>