We have not known about this issue. This is a new finding.
The lung development of children could be stunted by the release of micro-plastics from car tyres, according to an investigation.
Toxic particles emitted from all vehicles including exhaust fumes, metallised rubber and brake dust, are contributing to poor air quality in cities, a study for Channel 4's Dispatches discovered.
The findings came from an experiment conducted by the programme and scientists from King's College London (KCL).
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.
Professor Frank Kelly, of KCL, said: "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. We have not known about this issue. This is a new finding."
One in three children is breathing unsafe air and the modern car tyre is now around 50 percent plastic, according to the programme.
The Dispatches study monitored 50 pupils at Lordship Lane Primary School in Haringey, north London, 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, it said.
Around 9,000 Londoners die prematurely because of polluted air, according to the Mayor's Office. The Dispatches programme: Britain's Toxic Air Scandal, airs on Channel 4 at 8pm on Monday.
Thomas Hornall is a reporter for the Press Association.