Asia faced the highest burden, while heat, fires, emissions and cross-border transport worsened conditions across several regions

A according to the inaugural Atmosphere Watch report from the Copernicus Atmosphere Monitoring Service (CAMS) released on  30 September 2026, nearly 40% of the world’s population was exposed to dangerous levels of ground-level ozone during the first eight months of 2026, as extreme heat and human-generated emissions combined to worsen air quality.

The report noted that 34% of the global population experienced “extremely poor” ozone conditions between 1 Jan 2026 and 15 Sept 2026. Ozone concentrations in these areas were well above the World Health Organization’s eight-hour guideline of 100 micrograms per cubic meter.

Another 17% of people had encountered “very poor” conditions, while only about 5% lived with ozone levels classified as “good”, according to sources. Other report details:

  • The most affection region in the data was Asia, with 53% of its population experiencing extremely poor ozone conditions, while a further 22% faced very poor levels, according to CAMS. The exposure was associated with emissions from industry, transportation, urban growth, economic activity and other human sources. High population density has increased the number of people affected.
  • Europe also saw widespread exposure, with about half its population experiencing poor, very poor or extremely poor ozone levels.
  • North America recorded similarly persistent problems despite decades of emissions-control efforts. CAMS linked the lack of improvement to wildfire smoke, long-range pollution transport and climate-change effects.
  • The report also illustrated the borderless nature of atmospheric pollution. Smoke from North American wildfires crossed the Atlantic into Europe, while Saharan dust reached southern Europe and other regions.
  • Oceania was the cleanest region in the data, with its entire population experiencing good or fair ozone conditions.
  • South America performed better overall, although major cities including São Paulo and Rio de Janeiro recorded elevated levels.

CAMS monitors ozone, wildfire smoke and desert dust using satellite and ground observations alongside atmospheric modeling. With COP31 approaching, CAMS said the findings demonstrate that climate change, air quality and public health require coordinated international action.