Heat and Wildfires Drive Global Ozone Pollution Crisis

A third of the world's population breathed air the World Health Organization would call dangerously polluted this year. Ozone pollution, fed by record heat and wildfire smoke, reached extreme concentrations across much of the planet from January through mid-September, according to a report from the European Union's Copernicus Atmosphere Monitoring Service released Wednesday.

The analysis found that 34 percent of people worldwide were exposed to "extremely poor" air quality between Jan. 1 and Sept. 15, with ozone levels well above the World Health Organization's exposure guidance. Another 17 percent breathed "very poor" air. Only 5 percent experienced ozone levels the health agency classifies as good.

Ground-level ozone forms when heat and sunlight react with airborne emissions from wildfires, vehicles and industry. It can damage lung tissue, cause breathing problems and trigger asthma attacks. Ozone pollution is responsible for about sixty thousand premature deaths a year in Europe, Ian Marnane, an official at the European Environment Agency, told a media briefing.

Copernicus tracks air pollution and wildfire activity using satellite data and computer models. The service said this year's ozone pollution surge was driven in large part by record-breaking heat waves and wildfires that seared Europe and North America and sent smoke well beyond the borders of the countries where the fires burned. The same Copernicus programme has separately warned that the world's oceans are changing faster than ever (read the ocean warming report).

Heat waves and wildfires fed the surge

Climate change keeps creating the conditions that favor ozone formation. Prolonged heat waves gripped large parts of Europe and North America this summer, while wildfire seasons in both regions ranked among the most intense on record. Wind carried the smoke across long distances, where it mixed with traffic and industrial pollution to form ozone pollution far from the fires themselves.

Indonesia has also experienced major wildfires this year, and the report warns more may be coming. A warming El Niño pattern that began in June is expected to peak later this year, and according to the analysis it could drive additional fires across Southeast Asia, adding more ozone precursors to the air.

Ozone pollution levels in North America have stayed "relatively unchanged" despite ambitious emissions reduction policies, the report said, a sign that tailpipe and industrial cuts alone are not keeping pace with the added pollution load from hotter, fire-prone conditions. In Europe, regulation has been effective in reducing emissions of most air pollutants, but the report said ozone remains the exception. European regulators have also moved to tighten environmental claims, including a ban on greenwashing labels (how the ban works).

Asia carries the heaviest load

No region was hit harder than Asia. The continent had the highest ozone pollution exposure anywhere: 53 percent of its population breathed "extremely poor" air, and another 22 percent faced "very poor" levels. The report attributes the continent's exposure to industrialization, economic development and transportation, along with wildfires and the burning of agricultural residue.

Several major cities saw concentrations the report classed as extremely poor, including New Delhi, Dhaka, the Chinese megacity of Chongqing and Pakistan's Lahore. Two-thirds of the population in North America and 45 percent in Europe were exposed to "poor" or "very poor" air quality.

In Africa, smoke from forest fires, crop burning and cooking is a significant contributor to air pollution, while Saharan dust can travel as far as Europe. There, 8 percent of the population endured "extremely poor" air quality this year, and it was "very poor" or "poor" for 19 percent of the continent's population.

Cleaner pockets remain. Ozone levels were very high in the Brazilian city of São Paulo and extremely elevated in Rio de Janeiro, yet 81 percent of South America's population lived with "good" or "fair" air quality. Oceania fared best: about two-thirds of its population, including Australia and New Zealand, enjoyed "good" ozone levels, with the rest under "fair" conditions.

Pollution that crosses every border

The report's authors stress that no single country can fix this alone. "Air pollution does not stop at borders. It can travel thousands of kilometers, crossing continents and oceans and affecting air quality far from its source," CAMS director Laurence Rouil said in the report.

That reach is why Copernicus calls for coordinated regional and global action to limit the emissions behind ozone formation. The agency also notes a second problem: ozone pollution is tied to the climate itself, since ozone is a greenhouse gas, so higher levels can feed back into the climate system and make further formation more likely.

The findings show how the fight for clean air is changing. Despite decades of progress in cutting the most harmful air pollutants, ozone has proved harder to bring down as climate change keeps supplying the heat, sunlight and fire smoke its chemistry requires. With El Niño still building toward its peak, the coming months could bring further deterioration across parts of Asia and the Americas. Read the full AFP report on the Copernicus findings.