Study finds link between air pollution and cognitive decline in older adults | Health

By Stephen Beech

Long-term exposure to air pollution may harm the brain health of older people, warns a new study.

Researchers found that exposure to nitrogen dioxide (NO₂) and fine particulate matter (PM2.5) is linked to lower scores in key cognitive abilities, particularly language skills.

Nitrogen dioxide mainly enters the atmosphere through fuel combustion, originating from emissions of vehicles such as cars, trucks, and buses, as well as power plants and off-road machinery.

Fine particulate matter pollution in outdoor air often originates from the combustion of gasoline, oil, diesel fuel, or wood, and consists of tiny particles that can be inhaled deeply into the lungs.

The research team, led by scientists at University College London (UCL), analyzed data from 1,127 adults aged 65 and over living in England.

The researchers examined exposure to air pollution from 2008 to 2017 and assessed participants’ memory and executive function – such as making plans, solving problems and adapting to new situations – as well as overall cognitive function.

Participants completed a range of neurocognitive memory assessments, alongside immediate and delayed recall, backward counting tasks, and shape drawing.

The findings, published in The Journals of Gerontology: Series A, showed that those living in areas with the highest levels of nitrogen dioxide and fine particulate matter performed worse on cognitive tests compared to those living in areas with average pollution levels.

The researchers said that the “most compelling” evidence of association was observed in language skills, with people in the most polluted areas scoring in the bottom third of the cognitive tests performed.

The study also found that different sources of air pollution have varying effects on cognitive health. For example, pollution from industries, home heating, and combustion of fuels were strongly linked to poorer language performance.

The researchers didn’t examine the reasons behind their findings but suggest that it may be because increased air pollution exposure is most strongly associated with impairment in the temporal lobe – the part of the brain that is essential for language and semantic fluency.

Lead author Dr. Giorgio Di Gessa, of UCL, said: “Our study shows that air pollution is not just harmful to the lungs and heart but also to brain health, especially when people are exposed to high levels for long periods.

“The most consistent links we found were with language ability, which may indicate that certain pollutants have a specific effect on particular cognitive processes.”

The researchers urged policymakers to strengthen air quality regulations, especially in areas where pollution levels remain high.

Professor Paola Zaninotto, also of UCL, added: “By tracking pollution levels over a decade using high-quality data, our research provides robust evidence that sustained exposure to pollutants is damaging people’s brains.”