​Okay, this is scary news: scientists in the US have found evidence to suggest that exposure to sooty traffic fumes is costing children up to 3 IQ points of intelligence. Researchers Shakira Franco Suglia studied 200 children living in exposure to traffic pollution performed less when on intelligence tests than their cleaner breathing counterparts, even after taking factors such as social class! 

Advertisement - Continue Reading Below

This puts traffic pollution on par with lead in terms of its potential to stunt a child's brain development, although the researchers aren't yet sure exactly which components of exhaust fumes are responsible. But previous studies on animals suggest that particular (tiny invisible particles smaller than the boy's own cells) are likely to be culprits. These can enter the bloodstream through the lungs, but there is also evidence that they can penetrate into the central nervous system via the nose, travelling along the olfactory nerves that carry the sense of smell to the brain. Once there they can directly damage cells and also trigger inflammation that further injures the brain.

More From Cosmopolitan

This not as unlikely as it sounds. Studies on dogs living on the smoggy streets of Mexico City have been shown that animals exposed to the most pollution develop brain damage, similar to the changes seen in humans with Alzheimer's Disease.

Now the researchers need to track down what components of traffic pollution are responsible and determine how to remove them from the exhaust pipes of the millions of cars and trucks pounding the tarmac of big cities in every part of the world…so don't hold your breath. On second thoughts, do hold your breath!

While we're on the subject, did you know that The World Health Organization estimates that 1.2 million people are killed annually due to urban air pollution? A significant part of this pollution is generated by industry, energy production and vehicles.

If you live in Delhi, this news is even scarier, given how our pollution levels are seriously out of control. To read more about Delhi's pollution—and how it can harm your health—click here!

Information taken from The Naked Scientist by Chris Smith, INR 399, Hachette

What do you think?