Traffic fumes and piles of rubbish ruin sense of smell

OUR sense of smell is being damaged by modern life, a scientist claims, with traffic pollution and uncollected rubbish affecting our noses.

People living in areas where fumes were high had a worse ability to detect scents, as did people living in messy homes or near where rubbish bags were left to rot.

While being immune to such whiffs may seem like a boon, it is believed that losing the sense of smell increases the risk of developing mental health problems such as anxiety and depression.

Speaking at the American Association for the Advancement of Science (AAAS) annual meeting in Boston, Dr Kara Hoover, an expert in olfactory evolution, said: ‘Our sense of smell evolved in a very rich landscape in which we were interacting regularly with the environment. Now we’re not interacting with the environment and we’re in very polluted places.

‘Pollution is disrupting our sense of smell. That means it puts you at greater risk for mental health disorders such as depression and anxiety, and it also puts you at greater risk for physical health problems such as obesity.

‘It also puts you at greater risk for Science Correspondent in Boston social health problems – not being able to pick up on social cues from other human beings.’

Dr Hoover, associate professor of anthropology at the University of Alaska, Fairbanks, said losing the smell sense was linked to poor mental health in a number of ways.

‘People who have suffered from a loss of smell have increased anxiety over their own body odour because they don’t know if they smell bad or not,’ she said.

‘They’re anxious about not being able to smell danger like gas leaks or smoke. They suffer from poor quality of life and depression because they’re no longer engaging with food or loved ones in terms of their sense of smell.’

People from disadvantaged backgrounds are more at risk because of their greater exposure to pollution, she believes. Bus passengers were eight times more exposed to traffic pollution than car drivers.

Similarly, people who live in dirty and polluted areas, or whose rub- bish was not collected regularly, were likely to suffer more smell impairment.

She wanted to see more ‘greening’ of cities to provide a healthier environment.

Studies have also shown a link between loss of smell and obesity.

‘If you have an impaired sense of smell, you’re getting sated more from taste, and seeking richer tastes; salty and fatty food,’ said Dr Hoover.

A study of adults with a very strong sense of smell found they tended to have low body weight.

Dr Hoover has conducted research comparing the smelling ability of Homo sapiens and two now extinct human sub-species – Neanderthals and Denisovans.

Based on DNA analysis from their remains, she made the discovery that the Denisovans from Siberia had a ‘less functional’ sense of smell compared with early modern humans and Neanderthals.

‘Essentially, they can’t smell grass, so this might suggest that they have a different adaptation,’ said Dr Hoover. ‘Our sense of smell seems to be very similar to Neanderthals. They respond to odours the same way as us.’

The Denisovans’ DNA indicates that certain smells would not have been detectable to them.

‘Increased anxiety over body odour’