Extreme heat, pollution push up toxic ozone globally

A report by the Copernicus Atmosphere Monitoring Service said the combination of extreme heat and human-generated air pollution contributed to a rise in toxic ground-level ozone worldwide this year. About 40% of the world's population was exposed to dangerous ground-level ozone pollution in 2026, according to the report. Ground-level ozone can appear as brown-coloured haze and forms through chemical reactions involving sunlight and ultraviolet radiation. The pollution can harm human health, ecosystems and agricultural production. The number of people exposed to ozone pollution this year was higher than in the previous five years, the report said. In the United States, more than four in 10 people live in areas affected by air pollution. The report said smoke from wildfires and other pollutants can travel thousands of miles and reach distant areas. Although pollution from the burning of biological material has declined globally over recent decades, the number of people exposed to wildfire smoke has increased. The research said the main reason for the increase was the growing number of severe wildfires near densely populated areas, leaving large numbers of people exposed to smoke and air pollution.