Air pollution can have a “huge” negative effect on cognitive intelligence – especially amongst older men – according to a study released this past August.

The research is one of the first of its kind to focus on the links between air pollution and cognition in older people. It was undertaken by scientists at Peking University in Beijing, China and Yale University in the U.S. and was published in the Proceedings of the National Academy of Sciences journal. In particular, it found that long-term exposure to air pollution may impede overall cognitive performance.

The researchers’ sample set included a panel of over 25,000 people across 162 randomly chosen counties in China. The study was also based on daily readings for three atmospheric pollutants, namely sulphur dioxide (SO 2 ), nitrogen dioxide (NO 2 ) and particulate matter smaller than 10 micrometers (PM10) where the participants lived.

The research found that that accumulative exposure to air pollution impedes cognitive performance in verbal and math tests. It found that as people age, the negative effect becomes particularly pronounced on verbal scores, especially for men while, “the gender gap is particularly large for the less educated.” One of the reasons why the researchers suggest that older men with less education were worst affected by chronic exposure to air pollution is because those subjects often work in outdoor, manual jobs.

The scientists concluded that, “The damage on the aging brain by air pollution likely imposes substantial health and economic costs, considering that cognitive functioning is critical for the elderly for both running daily errands and making high-stake decisions.” Given this damaging effect of air pollution on cognition, particularly on the aging brain, “the study implies that the indirect effect on social welfare could be much larger than previously thought.”

“Polluted air can cause everyone to reduce their level of education by one year, which is huge,” Yale School of Public Health's Professor Xi Chen, one of the report's authors, said in an interview published in The Guardian.

The study also suggests that air pollution increases the risk of degenerative diseases such as Alzheimer's and other forms of dementia.

“Air pollution is a significant threat to public health and this study highlights the negative effect that such pollution may have on the ageing brain,” said Soraya Smaoun, Air Quality Coordinator at UN Environment. “A better understanding of the critical links between air pollution and health for policies and investments supporting cleaner transport and power generation, as well as energy-efficient housing and municipal waste management can reduce key sources of outdoor air pollution.”

According to the World Health Organization, seven million people die each year from exposure to polluted air, both indoor and outdoor. The three biggest killers which are associated to air pollution are stroke (2.2 million deaths), heart disease (2.0 million) and lung disease and cancer (1.7 million deaths).

The World Health Organization’s air quality database shows that that 97 per cent of cities in low- and middle-income countries with more than 100,000 inhabitants do not meet air quality guidelines presently. However, the percentage is much lower in higher income countries – 40 per cent.

What is being done about air pollution?

A worldwide movement to address air pollution is gradually taking shape and growing. Breathe Life – a global campaign headed by the Climate and Clean Air Coalition, the World Health Organization and UN Environment – is supporting a range of cleaner air initiatives that cover 39 cities, regions and countries, reaching over 80 million people.

Most major cities are still struggling to keep air pollution within acceptable levels as set out by the World Health Organization guidelines. However, by instituting policies and programmes to reduce transport and energy emissions, and by encouraging the use of clean energy, cities are leading change and improving the lives of a large number of people.

In 2018, the World Health Organization found that more than 57 per cent of cities in the Americas and more than 61 per cent of cities in Europe had seen a fall in both PM10 and PM2.5 particulate matter between 2010 and 2016.

The rise of renewable energy is also ideally positioned to make a big difference, with investment in new renewable sources outstripping fossil fuel investments every year.

“WHO: Breathe Life - How air pollution impacts your body”