Chronic exposure to air pollution may impair cognitive performance, with older, less educated men being the most affected, according to a new study conducted in China. The research, published in the Proceedings of the National Academy of Sciences, monitored the maths and verbal skills of approximately 20,000 participants over four years.
The study, a collaboration between Peking University and Yale University, measured levels of sulphur dioxide, nitrogen dioxide, and particulates smaller than 10 micrometres where participants lived. While establishing a link between pollution and lower test scores, the study did not prove cause and effect, and it remains unclear how much each pollutant contributes.
Researchers found that the negative impact on verbal tests increased with age, particularly for men and those with less education. Co-author Xi Chen of the Yale School of Public Health noted that the results across the life course are novel. The study also suggests that pollution raises the risk of degenerative diseases such as Alzheimer's and other dementias.
Previous research has shown air pollution harms cognitive abilities, but this study is distinguished by its detailed focus on age and gender differences in China. The findings have global relevance, as over 80% of the world's urban population breathes unsafe levels of air pollution, according to the World Health Organization, which estimates seven million premature deaths annually from air pollution.
The authors suggest that older, less educated men may be worst affected because they often work outdoor manual jobs. The study concludes that the indirect effect on social welfare could be much larger than previously thought, particularly for financial decision-making in old age. While specific to China, the findings shed light on other developing countries with severe air pollution.
