Air pollution causes a “huge” reduction in intelligence, according to new research, indicating that the damage to society of toxic air is far deeper than the well-known impacts on physical health.
The research was conducted in China, but is relevant across the world, with 95 percent of the global population breathing unsafe air. It found that high pollution levels led to significant drops in test scores in language and arithmetic, with the average impact equivalent to having lost a year of the person’s education.
“Polluted air can cause everyone to reduce their level of education by one year, which is huge,” said Xi Chen (陳希) at Yale School of Public Health in the Connecticut, a member of the research team. “But we know the effect is worse for the elderly, especially those over 64, and for men, and for those with low education. If we calculate [the loss] for those, it may be a few years of education.”
Illustration: Mountain People
Previous research has found that air pollution harms cognitive performance in students, but this is the first to examine people of all ages and the difference between men and women.
The damage in intelligence was worst for those over 64 years old, with serious consequences, Chen said.
“We usually make the most critical financial decisions in old age.” said Rebecca Daniels, of the UK public health charity Medact. “This report’s findings are extremely worrying.”
Air pollution causes 7 million premature deaths a year, but the harm to people’s mental abilities is less well known.
A recent study found toxic air was linked to “extremely high mortality” in people with mental disorders and earlier work linked it to increased mental illness in children, while another analysis found those living near busy roads had an increased risk of dementia.
The new work, published in the journal Proceedings of the National Academy of Sciences, analyzed language and arithmetic tests conducted as part of the China Family Panel Studies on 20,000 people across the nation between 2010 and 2014.
The scientists compared the test results with records of nitrogen dioxide and sulphur dioxide pollution.
They found the longer people were exposed to dirty air, the bigger the damage to intelligence, with language ability more harmed than mathematical ability and men more harmed than women. The researchers said this may result from differences in how male and female brains work.
Derrick Ho (何鴻澤), a research fellow and health geographer at the Hong Kong Polytechnic University, said the impact of air pollution on cognition was important and his group had similar preliminary findings in their work.
“It is because high air pollution can potentially be associated with oxidative stress, neuroinflammation, and neurodegeneration of humans,” he said.
Chen said air pollution was most likely to be the cause of the loss of intelligence, rather than simply being a correlation.
The study followed the same individuals as air pollution varied from one year to the next, meaning that many other possible causal factors such as genetic differences are automatically accounted for.
The scientists also accounted for the gradual decline in cognition seen as people age and ruled out people being more impatient or uncooperative during tests when pollution was high.
Air pollution was seen to have a short-term impact on intelligence as well and Chen said this could have important consequences, for example for students who have to take crucial entrance exams on polluted days.
“But there is no shortcut to solve this issue,” he said. “Governments really need to take concrete measures to reduce air pollution. That may benefit human capital, which is one of the most important driving forces of economic growth.”
In China, air pollution is declining but remains three times above WHO limits.
According to the WHO, 20 of the world’s most polluted cities are in developing countries. China, home to several of those cities, has been engaged in a “war against pollution “for the past five years.
The results would apply around the world, Chen added.
The damage to intelligence was likely to be incremental, he said, with a 1 milligram rise in pollution over three years equivalent to losing more than a month of education.
Small pollution particles are known to be especially damaging.
“That is the same wherever you live. As human beings we have more in common than is different,” he said.
Aarash Saleh, a registrar in respiratory medicine in the UK and part of the Doctors Against Diesel campaign, said: “This study adds to the concerning bank of evidence showing that exposure to air pollution can worsen our cognitive function. Road traffic is the biggest contributor to air pollution in residential areas and the government needs to act urgently to remove heavily polluting vehicles from our roads.”
“The UK’s air is illegally polluted and is harming people’s health every day. Current policies are not up to the scale of the challenge: government must commit to bringing air pollution below legal limits as soon as possible,” Daniels said.
Recently, China launched another diplomatic offensive against Taiwan, improperly linking its “one China principle” with UN General Assembly Resolution 2758 to constrain Taiwan’s diplomatic space. After Taiwan’s presidential election on Jan. 13, China persuaded Nauru to sever diplomatic ties with Taiwan. Nauru cited Resolution 2758 in its declaration of the diplomatic break. Subsequently, during the WHO Executive Board meeting that month, Beijing rallied countries including Venezuela, Zimbabwe, Belarus, Egypt, Nicaragua, Sri Lanka, Laos, Russia, Syria and Pakistan to reiterate the “one China principle” in their statements, and assert that “Resolution 2758 has settled the status of Taiwan” to hinder Taiwan’s
Singaporean Prime Minister Lee Hsien Loong’s (李顯龍) decision to step down after 19 years and hand power to his deputy, Lawrence Wong (黃循財), on May 15 was expected — though, perhaps, not so soon. Most political analysts had been eyeing an end-of-year handover, to ensure more time for Wong to study and shadow the role, ahead of general elections that must be called by November next year. Wong — who is currently both deputy prime minister and minister of finance — would need a combination of fresh ideas, wisdom and experience as he writes the nation’s next chapter. The world that
Can US dialogue and cooperation with the communist dictatorship in Beijing help avert a Taiwan Strait crisis? Or is US President Joe Biden playing into Chinese President Xi Jinping’s (習近平) hands? With America preoccupied with the wars in Europe and the Middle East, Biden is seeking better relations with Xi’s regime. The goal is to responsibly manage US-China competition and prevent unintended conflict, thereby hoping to create greater space for the two countries to work together in areas where their interests align. The existing wars have already stretched US military resources thin, and the last thing Biden wants is yet another war.
Since the Russian invasion of Ukraine in February 2022, people have been asking if Taiwan is the next Ukraine. At a G7 meeting of national leaders in January, Japanese Prime Minister Fumio Kishida warned that Taiwan “could be the next Ukraine” if Chinese aggression is not checked. NATO Secretary-General Jens Stoltenberg has said that if Russia is not defeated, then “today, it’s Ukraine, tomorrow it can be Taiwan.” China does not like this rhetoric. Its diplomats ask people to stop saying “Ukraine today, Taiwan tomorrow.” However, the rhetoric and stated ambition of Chinese President Xi Jinping (習近平) on Taiwan shows strong parallels with