One-third of the world’s population exposed to high ozone pollution

17:25

By: Azzat Manal

One-third of the world’s population exposed to high ozone pollution

Around one-third of the world’s population was exposed to very high levels of ground-level ozone pollution during the first eight months of 2026, according to a new assessment by the European Union’s Copernicus Atmosphere Monitoring Service. The findings highlight the increasingly close relationship between climate conditions, wildfires and air quality.

The analysis, covering the period from January 1 to September 15, found that 34% of the global population experienced air quality classified as “very poor” because of ozone concentrations. Another 17% were exposed to conditions categorized as “poor”, while only a small share of the global population experienced consistently good ozone levels.

Ground-level ozone is not emitted directly into the atmosphere. It forms when sunlight and heat trigger chemical reactions involving pollutants released by vehicles, industrial activity, wildfires and other sources. Unlike the protective ozone layer high in the atmosphere, ozone close to the ground is harmful to human health and can irritate lung tissue, aggravate asthma and contribute to breathing difficulties.

The Copernicus assessment underlines the role of extreme weather in worsening the problem. Heatwaves provide favorable conditions for ozone formation, while large wildfires release pollutants that can contribute to ozone production and send smoke over long distances. Pollution can therefore affect areas far from the original source of emissions.

Europe and North America experienced significant episodes of ozone pollution during 2026, with heatwaves and major wildfires contributing to deteriorating air quality. Smoke from fires can travel across national borders and, under suitable atmospheric conditions, affect populations thousands of kilometers away.

Asia recorded the highest proportion of people exposed to very poor ozone conditions. According to the assessment, 53% of the continent's population experienced very poor air quality linked to ozone, while another 22% were exposed to poor or very poor conditions. Rapid industrial development, transport emissions, agricultural burning and recurrent wildfires all contribute to the region's air-quality challenges.

Several major Asian cities recorded particularly high ozone concentrations during the period covered by the report, including New Delhi, Dhaka, Chongqing and Lahore. The combination of intense heat, urban emissions and regional pollution can create conditions in which ozone levels rise rapidly.

The situation also illustrates the difficulty of controlling ozone pollution compared with some other air pollutants. European policies have helped reduce emissions of several harmful pollutants over recent decades, but ozone has proved more difficult to tackle because its formation depends not only on local emissions but also on temperature, sunlight and atmospheric conditions.

North America also recorded significant exposure. Around two-thirds of the region's population experienced air quality classified as poor or very poor, despite long-standing policies aimed at reducing emissions. The assessment suggests that changing climate conditions can complicate efforts to achieve further improvements in ozone levels.

Africa recorded lower levels of very high ozone exposure overall, although the situation varied considerably between regions. About 8% of the continent's population experienced very poor ozone conditions, while 19% were exposed to air quality classified within the poor or very poor categories.

In South America, several major urban areas also experienced elevated ozone levels. São Paulo recorded particularly high concentrations, while Rio de Janeiro also experienced periods of very high ozone pollution. Despite these episodes, the assessment found that 81% of South America's population experienced ozone conditions ranging from good to acceptable.

Oceania recorded comparatively favorable results. Around 66% of the population of Australia and New Zealand experienced good ozone levels, while the remaining 34% were exposed to conditions classified as acceptable.

The findings underline the importance of combining air-pollution policies with climate action. Cutting emissions from transport, industry and other sources can reduce the pollutants involved in ozone formation, while measures to limit wildfire risks and adapt to more frequent heat extremes could also help protect air quality.

The Copernicus assessment demonstrates that ozone pollution is not solely a local environmental problem. Its formation is strongly influenced by weather and climate, while pollutants and wildfire smoke can travel across borders. As temperatures rise and extreme weather events become more frequent, monitoring and reducing ozone pollution is likely to remain a major public-health and environmental challenge.