A study from researchers in China and the United States has found that prolonged exposure to dirty air can have a significant impact on our cognitive abilities. The results of the study showed that breathing polluted air causes a “steep reduction” in scores on verbal and math tests, especially in older men. The study was published this week in the Proceedings of the National Academy of Sciences.
Researchers at the International Food Policy Research Institute (IFPRI) used data from the national China Family Panel Studies longitudinal survey to map the cognitive test scores of nearly 32,000 people over the age of 10. Their scores from tests taken between 2010 and 2014 were mapped against their exposure to short- and long-term air pollution. Their calculations took into account the gradual decline in cognition as people age, as well as the possibility that people were more impatient or uncooperative when the pollution levels were especially high.
The researchers found that high levels of pollution can trigger a decrease in language and arithmetic skills. The longer people were exposed to dirty air, the greater the damage to their intelligence levels. One of the report’s authors, Xi Chen of the Yale School of Public Health, said, “Polluted air can cause everyone to reduce their level of education by one year, which is huge.”
This latest study was the first to examine air pollution-related cognitive performance in people of all ages. The team also studied the differences that occurred in men and women. They found that the decline in verbal scores was particularly pronounced among older, less educated men.
Air pollution is a serious problem for people across the globe. According to the World Health Organization (WHO), nine out of every 10 people on the planet live in areas where the air quality exceeds WHO guideline limits. Nearly all cities in low to middle-income countries with more than a million residents fail to meet minimum WHO guidelines, with the worst affected regions being Africa and Asia. Roughly 4.2 million people die each year from exposure to outdoor air pollution.