This WHO report synthesizes existing WHO and United Nations guidance related to environmental hazards extreme heat, air pollution, and solar ultraviolet (UV) radiation in the context of mass gatherings and large public events. It identifies key knowledge gaps, highlights the intersecting health risks these combined hazards pose to event participants and staff, and proposes a research agenda to inform future guidance and practical tools for event planners and health authorities. The document aims to protect populations from compound environmental stressors during major gatherings, especially as climate change increases the frequency and intensity of heat and air pollution events.
Key Insights:
• Extreme heat, air pollution, and UV exposure often co-occur and create compound health risks for individuals at mass events, particularly vulnerable people and outdoor workers.
• Rising global temperatures exacerbate both heat stress and ambient pollution levels, while ozone depletion increases harmful UV exposure.
• The report highlights research gaps and the need for evidence-based operational guidance on monitoring, early warning systems, and protective interventions for mass gatherings.
• Recommendations are intended to inform planners, policymakers, health workers, and organizations responsible for event planning and public safety.
