The findings came from an experiment conducted by Channel 4's Dispatches programme and scientists from King's College London. 

Air pollution is linked to the early deaths of about 40,000 people a year in the UK and causes problems like heart and lung disease and asthma.

"We know that some of the components from brake wear, together with micro-plastics from tyres, will be irritating and causing reactions in the lung, which over time would not be good for our health," Professor Frank Kelly from Kings College said. 

"We have not known about this issue. This is a new finding."

The modern car tyre is now around 50 per cent plastic, according to the programme.

The Dispatches study monitored 50 pupils at a North London school, which found they were exposed to high levels of nitrogen dioxide, an inflammatory pollutant.

Measures including planting hedges around the school, fitting mesh on windows and installing an air-purifier in classrooms led to a drop in nitrogen dioxide exposure by around one-fifth.

Around 9000 Londoners die prematurely because of polluted air, according to the Mayor's Office.

 

AAP