One-third of world's population exposed to high ozone levels in 2026

Nearly one-third of the world’s population was exposed to very high levels of ground-level ozone pollution in 2026, due to heatwaves, wildfires, and emissions from human activities, according to a report issued today by the European Union.

A new analysis by the EU’s Copernicus Atmosphere Monitoring Service, covering the first eight months of the year, highlights the close link between climate change and air pollution.

Ground-level ozone forms when heat and sunlight react with emissions from wildfires, vehicles, and industrial activities, potentially causing lung tissue damage, breathing difficulties, asthma attacks, and other health problems.

Despite progress made in recent decades in reducing emissions of the most harmful air pollutants, combating ozone pollution remains more challenging, as climate change creates favorable conditions for its formation.

Record heatwaves and wildfires that swept across Europe and North America this year exacerbated ozone pollution, as smoke plumes extended far beyond their borders.

Indonesia also experienced large-scale wildfires, while the report warned that the El Niño climate phenomenon, which began in June and is expected to peak later this year, could trigger further fires in Southeast Asia.

Laurence Rouil, director of the Copernicus Atmosphere Monitoring Service, stated in the report titled “Atmosphere Monitoring” that “air pollution does not respect borders; it can travel thousands of kilometers, crossing continents and oceans, affecting air quality in areas far from its source.”

The report showed that 34 percent of the world’s population was exposed to air classified as “very poor” between January 1 and September 15, with ozone concentrations far exceeding the levels recommended by the World Health Organization (WHO).

The WHO sets the recommended maximum exposure limit for ozone at 100 micrograms per cubic meter of air, calculated as an eight-hour average.

Another 17 percent of the global population was exposed to air classified as “poor,” while only 5 percent were exposed to good ozone levels.

India’s New Delhi, Bangladesh’s capital Dhaka, China’s sprawling city of Chongqing, and Pakistan’s Lahore were among the cities that recorded very high levels of ozone pollution.

In North America, two-thirds of the population was exposed to air classified as “poor” or “very poor,” compared to 45 percent of Europe’s population.

In South America, Brazil’s São Paulo recorded very high ozone levels, while Rio de Janeiro experienced extremely high levels.

Oceania, which includes Australia and New Zealand, performed better, with 66 percent of its population enjoying good ozone levels and 34 percent exposed to levels classified as “acceptable.”