Long term exposure to air pollution may cause significant harm to cognitive performance, new research has suggested.
Carried out in China, findings of the study were published yesterday (27 August) in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).
As part of the study, academics from Peking University and the Yale School of Public Health looked at the impact of cumulative and transitory exposures to air pollution over time alongside cognitive performance through test results in over 30,000 individuals.
Through the findings, the research team have suggested that impacts of air pollution could become more pronounced as people age. The effect is particularly large for less educated men older than 64, the study suggested.
Researchers concluded: “This paper estimates the contemporaneous and cumulative impacts of air pollution on cognition by matching the scores of verbal and math tests given to people age 10 and above in a nationally representative survey with local air quality data according to the exact dates and locations of the interviews.
“We find that accumulative exposure to air pollution impedes verbal test scores. As people age, the negative effect becomes more pronounced, especially for men. The gender gap is particularly large for the less educated.
“Our findings about the damaging effect of air pollution on cognition, particularly on the aging brain, imply that the indirect effect on social welfare could be much larger than previously thought. A narrow focus on the negative effect on health may underestimate the total cost of air pollution.”
The cognitive test scores came from the CFPS, a nationally representative survey of Chinese families and individuals, which includes 24 standardized mathematics questions and 34 word-recognition questions.
The survey also provides exact information about the geographic locations and dates of interviews for all respondents, against which researchers were able to compare data from the Air Pollution Index (API) containing daily readings of sulphur dioxide (SO2), nitrogen dioxide (NO2) and particulate matter (PM10).
Researchers also believed that reducing the population-weighted annual mean concentration of PM10 over 2014 in China to levels below the National Ambient Air Quality Standards published by the US Environmental Protection Agency would on average lift verbal test scores by 2.41 points and maths test scores by 0.39 point.