Air pollution exposure disparities among ethnic groups in high-income countries: A scoping review

Background: The adverse health effects of air pollution are well-established. Previous reviews have highlighted disparities in air pollution exposure between minoritized ethnic groups and majoritized ethnic groups. However, these reviews primarily focused on proximity to pollution sources rather than objectively measured concentrations. This scoping review aims to provide an overview of the extent of inequalities in objectively measured air pollution exposure among ethnic groups in high-income countries. Methods: We systematically searched PubMed, Scopus, Web of Science, and Google Scholar for studies published in English, that reported on objectively measured air pollution exposure stratified by ethnic groups in high-income countries. Data on study characteristics and air pollution exposure were extracted. Results: The majority of all 55 included studies were conducted in North America (n = 46), followed by Europe (n = 8), and Oceania (n = 1). Across studies, 25 ethnic groups were identified, with African American, Hispanic, Latino, and Asian populations being the most studied minoritized ethnic groups. PM_2.5 was the most studied (n = 38) air pollutant. Eighteen studies statistically tested differences in exposure across ethnic groups. Thirteen studies reported significantly higher air pollution exposure among minoritized ethnic populations compared to the majoritized ethnic population, and five studies showed mixed evidence. Conclusions: This review highlights the extent of disparities in air pollution exposure among ethnic groups in high-income countries. It underscores the need for further research to understand the contributing factors and potential interventions to address these disparities.