A new study suggests that long-term exposure to air pollution can have a negative impact on cognitive function, which can lead to additional health and economic costs.
The study, published in Proceedings of the National Academy of Sciences of the United States of America, found not only that long-term exposure to air pollution could decrease cognitive function, but that this effect becomes more pronounced as people age, particularly for men and people who are less educated.
How did the team undertake the research?
The researchers, based at Peking University, Beijing, China, examined air quality data to determine the concentrations of pollutants sulphur dioxide, nitrogen dioxide and particulate matter smaller than 10 μm, in areas where people took verbal and maths tests as part of a nationally representative longitudinal survey.
The team then compared the results, and found evidence that the cognitive performance of those taking the test was impeded by their long-term exposure to the pollutants in question; although, it is not yet clear to what extent each of the pollutants is responsible for the cognitive impairment, and the study did not take into account other common pollutants, such as carbon monoxide, ozone and larger particulate matter.
What wider health impact do the results indicate?
The researchers speculate that the challenges of cognitive impairment caused by exposure to air pollution, particularly in older people, could impose significant health and economic costs on a broad scale. Long-term exposure to air pollution could compound and exacerbate the natural deterioration of cognitive function, which is vital for elderly people in both day-to-day life and also in making high-stakes decisions.
However, cutting the annual mean concentration of particulate matter across China to meet environmental standards (50 μg/m3) would move people from the median to the 63rd percentile in verbal test scores, and the 58th percentile in maths test scores.
According to the World Health Organization, which surveyed more than 4,300 cities worldwide, found that 80% of the populations surveyed lived in areas with unsafe levels of particulate matter and other pollutants.