Global solar UV index: a practical guide

This guide presents an overview of ultraviolet (UV) radiation, its sources, and associated health effects, emphasizing the urgent need for public education on sun safety. Developed collaboratively by leading international organizations, the document details the formulation and purpose of a standardized index that quantifies solar UV radiation at the Earth’s surface. It discusses the primary health risks of overexposure, including acute conditions such as sunburn and photokeratitis, as well as chronic issues such as various skin cancers, cataracts, and immune system impairment. The document outlines targeted educational strategies, recommending specific protective measures—such as seeking shade, wearing protective clothing and sunglasses, and properly applying sunscreen—to reduce risk, particularly among vulnerable groups like children. A clear framework for conveying the index to the public is provided, with guidance on harmonized messaging, color-coded risk categories, and practical sun protection advice.