According to the World Health Organization, 91 percent of the world’s population live in areas where pollution is classed as dangerous to human health and which exceeds current air quality standards for safety. Ambient air pollution in both cities and rural areas was estimated to cause 4.2 million premature deaths worldwide per year in 2016.
This itself leads to well-established ill-health effects associated with lung disease and cardiovascular health. However, new research presents an additional concern and this draws a connection between levels of air pollution and cognitive decline.
The connection is based on research undertaken by Chinese scientists where studies suggest air pollution is causing significant cognitive decline. Parts of China are heavily impacted by air pollution. In Beijing, for example, pollution spikes in winter, when coal is required for heating.
The new research was conducted at Beijing Normal University. The researchers assessed mathematics and verbal scores from 31,000 Chinese citizens. Using this, the researchers matched the test score data with air quality data collected between 2010 to 2014. The matching of these data sets indicated levels of cognitive decline as shown in the test scores in areas where pollution was most severe.
While the research outcome stands more with correlation than causation, the researchers attempted to control the experiment for ‘natural’ cognitive decline which occurs as people age.
The reason given why pollution can affect cognition is because some types of particles found in pollution can disrupt the function of this neural safeguard provided by the blood-brain barrier. This has been shown in some people exposed long-term to poor air quality indicating inflammation of brain tissue plus an altered immune response.
The researchers fear that the damage on the aging brain by air pollution likely imposes substantial health and economic costs.
According to one of the researchers, Xin Zhang: “We speculate that air pollution probably puts greater damage on the white matter in the brain, which is associated with language ability. More research is needed to understand the mechanisms.”
The research has been published in the journal PNAS, with the article titled “The impact of exposure to air pollution on cognitive performance.”
