Temporary increases in air pollution can impair memory and thinking in older men, research shows that even short-term spikes in airborne particles can be harmful to brain health.
Scientists found that men’s cognitive performance dropped as a result of increased air pollution in the month before testing, even when peak levels remained below safe thresholds for the test. toxic air set by the World Health Organization and national regulators.
The results are supported by growing evidence that exposure to fine particles in the air, largely from road vehicles and industry, is harmful not only to the heart and lungs, but also for the delicate neural tissues of the brain.
Researchers in the United States and China compiled several cognitive test results from nearly 1,000 men living in the Greater Boston area and compared them to local levels of PM2.5 – less airborne particles. 2.5 microns in diameter. The men involved in the study were white and were on average 69 years old.
Writing in Nature Aging, the scientists describe how higher levels of PM2.5 up to four weeks before testing were linked to poorer cognitive performance on tasks ranging from word memory to number recall and fluency. verbal. The effect was clear even when PM2.5 concentrations remained below 10 micrograms per cubic meter, the WHO benchmark that is routinely violated in London and many other cities.
Oddly, the study found evidence that test results were less affected by short-term increases in air pollution if men took aspirin or other nonsteroidal anti-inflammatory drugs, called NSAIDs. . “Our study indicates that short-term exposure to air pollution may be linked to short-term alterations in cognitive function and that NSAIDs may alter this relationship,” the authors write. According to one line of thought, these pain relievers can help by reducing inflammation triggered by fine particles entering the brain.
While the WHO says PM2.5 levels should not exceed an annual average of 10 micrograms per cubic meter, the UK has adopted an upper limit of 25 micrograms per cubic meter. The government’s air quality index considers PM2.5 levels below 35 micrograms per cubic meter “low.”
Last month Philip Barlow, the South London coroner who found air pollution to be a cause of death for 9-year-old Ella Kissi-Debrah, said the UK must adopt levels legally binding lower for particulate air pollution.
The impact of toxic air on respiratory and cardiovascular health is well established, and the evidence for brain damage is growing. Studies have linked air pollution to reduced intelligence and dementia. In February, work led by Professor Jamie Pearce at the University of Edinburgh found that exposure to air pollution in childhood was linked to poorer thinking skills later in life.
“The results really underscore the impact of air pollution on human health,” said Dr Joanne Ryan, head of research in biological neuropsychiatry and dementia at Monash University in Melbourne, who did not participate in the latest. works. “The significance of this study is that the results align with a potential causal link of air pollution on brain function and they suggest that it is not just the very high levels of prolonged pollution that are of concern. The study found that even relatively low levels of air pollution can negatively impact cognitive functions over short periods of time.
“This work confirms that there is a link between air pollution and the functioning of the aging brain,” said Andrea Baccarelli, lead author of the study and professor of environmental health sciences at Columbia University. New York. “These short-term effects are reversible: when air pollution goes away, our brains restart and start to return to their original level. However, multiple occurrences of these higher exposures cause permanent damage.
“Our results do not yet suggest that all older people should take anti-inflammatory drugs, as these are drugs with side effects that we cannot take lightly,” he added. “More broadly, reducing inflammation through healthy diets, such as more fruits, vegetables, and fiber, or through regular exercise, can go a long way to not only making us generally healthier. , but also to make us more resilient in the face of environmental threats such as air pollution. ”