It is widely known that air pollution is harmful to the health, but a new study shows that it takes a toll on intelligence too.
New research shows that polluted air causes a sharp drop in math and verbal test scores, and the effects become worse over time.
Air Pollution Affects Cognitive Intelligence
In the study published in the Proceedings of the National Academy of Sciences, researchers from Peking University in China and Yale University in the United States analyzed data from nearly 32,000 people in China to find the link between exposure to air pollution and cognitive performance.
The team discovered a clear decline in math and verbal test scores with the negative effects getting stronger as individuals age, especially in men and less educated people.
The participants, all over the age of 10, were monitored from 2010 to 2014, with their cognitive test scores compared against air pollution exposure through their geographical location and local air quality data. Air quality is based on daily measurements of three pollutants: sulfur dioxide, nitrogen dioxide, and particulate matter smaller than 10 μm.
BBC reports that the more pronounced effect of air pollution on older, less educated men was attributed to this group's likelihood in working outdoor manual jobs, which exposes them more directly to the polluted air.
The Effect On Elderly Has Large-Scale Implications
With the aging population found to be the most vulnerable, the authors point out that there's also a significant health and economic cost that arises from the issue.
Cognitive decline is a risk factor for Alzheimer's disease and other types of dementia in the elderly, the former of which amounted to $226 billion of health services and 18 billion labor hours of unpaid caregiving in 2015, according to the study.
"Our findings on the damaging effect of air pollution on cognition imply that the indirect effect of pollution on social welfare could be much larger than previously thought," Xiaobo Zhang, one of the study authors from the International Food Policy Research Institute and a professor from Peking University, says in a statement.
He adds that their findings have policy implications that have been neglected in policy discussions so far.
Recommended Course Of Action
Basically, the authors suggest limiting the amount of air pollution in the world. Currently, the World Health Organization reveals that 91 percent of the global population live in areas where air quality does not adhere to WHO guidelines.
According to the study author's calculations, simply reducing the particulate matter concentrations to the Unites States Environmental Protection Agency's standard of 50 μg/m3 would boost people from the median to the 63rd percentile in verbal test scores and the 58th percentile in math test scores.