The Grapevine

Air Pollution Affects Intelligence, Equated To Losing 1 Year Of Education

Exposure to air pollution not only affects our physical health but also reduces our intelligence levels, according to new findings from a study conducted in China. Participants showed a decline in cognitive performance in both verbal and math tests.

The study titled "The impact of exposure to air pollution on cognitive performance" was published in the Proceedings of the National Academy of Sciences on Aug. 27.

Estimations by the World Health Organization (WHO) suggest that nearly seven million deaths around the world are caused by air pollution every year. Apart from leading to respiratory illnesses, exposure to pollutants can also damage our immune system, cause birth complications, increase the risk of heart-related problems, and more.

But how pollution could affect something like intelligence has not clearly been established yet. While past research has examined students alone, the new study tracked the long-term effects in people of all ages.

To understand how cognition could change when a person is exposed to polluted air over a long period, 20,000 people were asked to write tests measuring their language and arithmetic skills. The same participants, who were based in various Chinese counties, were tested in 2010 and 2014.

The longer a person was exposed to polluted air, the more damage they incurred with regard to their intelligence. Between the two tests, language ability faced more harm than mathematical ability. Age and gender were found to be factors as older adults and male participants experienced more damage than their counterparts.

To illustrate just how dangerous the exposure could be, the impact of high levels of air pollution was equated to losing one year of education. "But we know the effect is worse for the elderly, especially those over 64, and for men, and for those with low education," said co-author Xi Chen from the Yale School of Public Health.

For these individuals, the loss may even be equivalent to a few years of education. Individuals with low levels of education were at risk because they were more likely to perform manual labor i.e. work outside all day long, thus being exposed to more pollution.

It was not only long-term effects as the researchers noted the possible risk of a short-term impact on intelligence. This can affect us in crucial situations, such as children being scheduled to write a really important exam on a day with particularly high levels of pollution.

"But there is no shortcut to solve this issue," Chen 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."

While the study examined residents of China, the findings were relevant across most of the world with a strong emphasis on developing nations. According to a 2018 WHO report, nine out of ten people worldwide breathe polluted air.