nIf you are exposed over a long time to two air pollutants, ‘particulate matter 2.5’ and ‘nitrous oxide’, which are both commonly found in cities around the world, there is a high chance that you risk of developing dementia later in life, according to a study published in the Journal of Alzheimer’s Disease.

“This is concerning because the World Health Organisation (WHO) estimates 91 per cent of the world’s population lives in places where air quality exceeds WHO guideline limits,” Study co-author Neuroscience Research Australia’s Dr Ruth Peters said.

He added that it’s difficult for people to reduce exposure if they live where pollution levels are high.

Dementia is a neurodegenerative disease — characterized by a decline in performance and cognitive impairment in multiple domains and affects a person’s independence in doing activities of daily living.

“This research shows that government regulation that reduces our exposure to air pollution has a huge potential health and economic benefit.”’

Researchers believe air pollutants can increase inflammation in bodies and raise the risk of having a stroke, which increases the likelihood of developing dementia. Preventing dementia is a focus because it has become a growing health problem, which affects some 50 million people around the world.

The WHO estimates that nearly 10 million people each year develop the condition.

The study brought together research on people living in Canada, Sweden, Taiwan, United Kingdom and the United States.

The study is important in the context of India which is home to 15 of the 20 most polluted cities in the world with some studies indicating nearly 700 million Indians are exposed to unhealthy air.