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at Lancaster University in the UK has found that tiny particles of iron oxide in our brains probably come from the we breathe.

These magnetic particles have been linked to Alzheimer’s disease, and are thought to generate reactive compounds that can . We have known for some time that there are magnetite particles in our brains, but until now, it was thought that they came from natural sources.

Maher’s team found that the particles are mostly round in shape – a structure that suggests they form when fuel is burned, and may then get into the nerves in our noses when we breathe fumes in. “Because magnetite is known to be so toxic to the brain, it makes you see the atmosphere you’re breathing in in a different light,” says Maher.

She has now made changes to her lifestyle to avoid breathing in too many nanoparticles. “These findings are sufficiently alarming for me to alter my behaviour,” she says. “If I’m walking in a really busy street, I walk as far from the kerbside as I can. The concentration of particulate matter drops even across the pavement’s width.”

When walking uphill, Maher may cross the road to walk next to the traffic going downhill. “The vehicles going uphill generate more particulate matter.”

“If I’m driving and I pull up behind a car, I’m not right up to the bumper,” she says. “In heavy traffic, the safest option is to have your air on recirculate. I choose my route so I’m on the back roads.”

“Everybody deserves to have this information so they can take steps to reduce their own exposure level,” says Maher.

Read more:��Air pollution puts tiny magnetic particles in your brain