Abstract
INTRODUCTION: Ambient air pollution is an important contributor to cancer risk. While previous studies have examined the impact of air pollution on cancer mortality, they have largely overlooked how population vulnerability indicators, such as socioeconomic status, interact with air pollution to influence cancer mortality across cancer types. This review aimed to address this gap by systematically reviewing these effect modifications and providing insights to inform efforts aimed at reducing differential health burdens. METHODS: We searched PubMed, Embase, Scopus, and Web of Science for studies conducted in the U.S. published between January 1, 1994, and January 27, 2024. Covidence was used to manage study selection and data extraction, including study design, air pollutants, population vulnerability indicators (e.g., urbanicity, proximity to pollution, socioeconomic status, race/ethnicity), exposure assessment methods, cancer types, and findings. RESULTS: We identified 15 articles and found that the associations between air pollution and cancer mortality varied by urbanicity and socioeconomic status. A slight majority of studies reported stronger associations in less urbanized populations and lower-SES groups. Black individuals experienced higher cancer mortality risks from air pollution than Whites, while findings for Hispanics and Asians were inconsistent. CONCLUSION: Air pollution exposure and population vulnerability indicators jointly contribute to disparities in cancer mortality, disproportionately affecting vulnerable populations such as those in less urbanized areas and marginalized racial and ethnic groups. Targeted research and policies are needed to mitigate these inequities, improve air quality, and reduce cancer mortality in high-risk communities.