Mega-Events, Air Pollution and Health Outcomes: A Systematic Review

Air pollution represents a public health threat; it is co-responsible for millions of premature deaths annually and economic losses. Mega-events create abrupt changes in air pollution providing quasi-experimental settings to investigate related health impacts. This systematic review synthesizes the evidence on air pollution level changes during mega-events and associated short-term health effects, including mortality, hospitalizations and early biological responses. A literature search was conducted in PubMed, Embase, Scopus and Web of Science up to 7 April 2025. Study quality was evaluated using the EPHPP Quality Assessment Tool for Quantitative Studies. Thirty-one studies met the inclusion criteria. Mega-events without effective air pollution control measures were associated with increased pollutant levels and higher risks of respiratory and cardiovascular morbidity. Biomarker studies demonstrated rapid and reversible changes in oxidative stress and inflammatory biomarkers in response to short-term variations in air pollution. Instead, significant reductions in air pollution during mega-events were observed upon emission control measures. The evidence is predominantly from Asian countries, no Europe/Africa studies and only one from North America, limiting generalizability. Findings indicate that mega-events may influence air quality which affects human health, reinforcing the value of temporary emission control measures strategies for future mega-events. The systematic review was registered with Prospero (CRD420251032553).