Exposure to high levels of pollution can impact intelligence, says study
Constant exposure to high levels of toxic air could harm people’s cognitive intelligence, according to a new study.
Published in the journal Proceedings of the National Academy of Sciences, the study examined the maths and verbal skills of 20,000 people in China over four years (2010–2014) and found that high pollution levels led to a significant drop in language and arithmetic test scores.
Researchers from Beijing’s Peking University and US-based Yale University tested people of both sexes aged 10 and above with 24 standardised maths questions and 34 word-recognition questions, and then compared the results with records of nitrogen dioxide and sulphur dioxide pollution. Carbon monoxide, ozone and larger particulates were not included.
The results revealed that the longer people were exposed to dirty air, the bigger the short-term impact on intelligence, with language ability harmed more than mathematical. On average, more men were impacted than women and researchers said this may be a result in differences in how male and female brains work.
The damage to intelligence was also likely to be incremental, the report said, with a 1mg rise in pollution over three years equivalent to losing more than a month of education.
Xi Chen from Yale School of Public Health anda member of the research team, said: “Polluted air can cause everyone to reduce their level of education by one year, which is huge. 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.”
Previous research in the field has found that pollution can harm cognitive performance in students, but this is the first to examine people of all ages. Chen also said that pollution was most likely the cause of loss of intelligence rather than simply a correlation because they followed the same individuals as the pollution varied from year-to-year, stating that other possible causal factors such as genetic differences were accounted for.
“There is no shortcut to solve this issue. 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,” added Chen.