In 2005 Beijing was crowned the smog capital of the world. Concerns about air pollution and athlete health overshadowed preparations for the 2008 Olympic Games and required industry and traffic shutdowns to clean the air during the event itself. Now, a team of researchers at Chinese, German and Canadian universities have tracked the impacts of deteriorating air at that time. They found that particle pollution deaths in China were increasing at about 213,000 a year and peaked at 2.6mn people in 2005. More positively, the impact of rapid improvements in China’s air pollution were also seen, with decreases of 59,000 deaths a year from 2013 to 2019. Air pollution in China is still far worse than in many developed countries. In 2019, about half of China’s cities failed to meet their own national standards, let alone those from the World Health Organization. The country now has comprehensive air pollution action plans to win what the government terms the “blue skies defence war”. With big investments in renewable energy and future decarbonisation targets, at first sight, it looks like China has turned a corner. However, the research contains a warning. Without accelerated action, air pollution deaths in China will begin to rise soon. This is due to a growing ageing population with the underlying vulnerabilities that come in later life. Prof Michael Brauer from the University of British Columbia, who was not involved in the new research, said: “The same level of air pollution will have a greater impact on an older and less healthy population with increased levels of diseases impacted by air pollution – many of which increase with age. These include lung cancer, diabetes, lung and chronic heart disease.” The scale of the challenge is clear in the latest research. China’s air pollution-related deaths are projected to increase by between 116,000 and 181,000 a year from 2030 to 2060, despite continued improvements in particle pollution and improvements in health care. Brauer explained the implications: “So, for the future, for China to even to just tread water, it needs to reduce air pollution even more aggressively.” In the UK, the effect of an ageing population is also predicted to reduce the gains from measures to reduce air pollution, but a preliminary 2022 study suggests that will not completely outweigh them. Brauer explained that many other countries face a similar challenge to China: “Even India’s population is ageing, but it will take 20 years to reach the age where China is today. Some of the countries in eastern Europe such as Bulgaria and Poland are highly polluted and have populations that are even older than China’s.” This is especially important as EU governments finalise new legal targets for air pollution.