Nearly 40% of the World’s Population Exposed to Dangerous Ground-Level Ozone in 2026
World
Nearly 40% of the world’s population was exposed to extremely high levels of ground-level ozone during the first eight months of 2026. Asia was the most affected region, followed by Europe and North America.
The findings are contained in the new Atmosphere Watch report by the Copernicus Atmosphere Monitoring Service (CAMS), covering the first eight months of the year. According to the analysis, roughly 50% of the global population was exposed to very poor or extremely poor air quality due to ozone concentrations, while only 5% lived in areas with “good” long-term ozone levels.
Ground-level ozone is different from the ozone layer that protects the Earth from ultraviolet radiation. It is a secondary pollutant formed near the surface through chemical reactions involving pollutants such as nitrogen oxides and volatile organic compounds under sunlight and high temperatures. As a result, periods of extreme heat can contribute to higher ozone concentrations.
According to CAMS, Asia was the region most affected by ozone pollution worldwide. High concentrations were recorded particularly in densely populated areas, especially in South Asia. In Europe, repeated heatwaves from June to August contributed to increased ozone levels, while concentrations in North America remained high, partly due to ozone-precursor emissions from major wildfires.
Wildfire smoke contains substances involved in ozone formation and can travel thousands of kilometres. CAMS also highlights the role of climate change: higher temperatures and more frequent heatwaves create conditions that favour the formation of ground-level ozone.
“Ozone pollution is a stark reminder of how interconnected our atmosphere, climate, health, and livelihoods really are,” said Laurence Rouil, Director of CAMS. She noted that air pollution and climate change affect the chemistry of the air, the health of ecosystems and the ability to grow food.
Oceania, meanwhile, remained one of the regions with the lowest ozone exposure. During the first eight months of 2026, 100% of its population lived in areas classified as having “good” or “fair” ozone levels.
Ground-level ozone is different from the ozone layer that protects the Earth from ultraviolet radiation. It is a secondary pollutant formed near the surface through chemical reactions involving pollutants such as nitrogen oxides and volatile organic compounds under sunlight and high temperatures. As a result, periods of extreme heat can contribute to higher ozone concentrations.
According to CAMS, Asia was the region most affected by ozone pollution worldwide. High concentrations were recorded particularly in densely populated areas, especially in South Asia. In Europe, repeated heatwaves from June to August contributed to increased ozone levels, while concentrations in North America remained high, partly due to ozone-precursor emissions from major wildfires.
Wildfire smoke contains substances involved in ozone formation and can travel thousands of kilometres. CAMS also highlights the role of climate change: higher temperatures and more frequent heatwaves create conditions that favour the formation of ground-level ozone.
“Ozone pollution is a stark reminder of how interconnected our atmosphere, climate, health, and livelihoods really are,” said Laurence Rouil, Director of CAMS. She noted that air pollution and climate change affect the chemistry of the air, the health of ecosystems and the ability to grow food.
Oceania, meanwhile, remained one of the regions with the lowest ozone exposure. During the first eight months of 2026, 100% of its population lived in areas classified as having “good” or “fair” ozone levels.
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