Tropospheric ozone exposure affects 40% of global population

A new global analysis by the Copernicus Atmosphere Monitoring Service (CAMS) reveals that during the first eight months of 2026, nearly 40% of the world's population was exposed to extremely high levels of tropospheric ozone. In contrast, only 5% of the population was exposed to levels considered good by World Health Organization standards.

Tropospheric ozone is a secondary pollutant that is not emitted directly into the atmosphere. Instead, it forms when precursor pollutants, such as nitrogen oxides and volatile organic compounds, react in the presence of sunlight and high temperatures. This process is exacerbated by heatwaves and climate change, a phenomenon referred to as the ‘climate penalty for ozone.’

The report highlights that ozone and its precursors can travel long distances across borders, affecting areas far from their original emission sources. Beyond human health risks, high ozone levels also impact ecosystems and crop yields. The CAMS analysis utilizes data from satellites, aircraft, and ground networks to provide a comprehensive view of atmospheric conditions and the combined influence of human emissions and extreme weather events.