Scrapping speed bumps could help protect city dwellers against ‘London throat’ because braking releases toxic dust which may trigger coughs and colds, scientists have said.
Urbanites often suffer from intermittent bouts of runny noses and brain fog, which experts have long-suspected are caused by pollution.
Dubbed ‘London Throat’ this ongoing low-level illness can lead to more serious infections such as pneumonia and bronchitis.
Now scientists at King’s College London and Imperial College London have found that brake dust – tiny metal particles released when a car brakes – may damage the immune system, preventing cells called macrophages from engulfing bacteria and clearing them away.
Previously the National Institute of Clinical Excellence (NICE) has suggested that speed bumps should be removed to cut traffic pollution because they force motorists to keep accelerating and decelerating.
Study author Dr Liza Selley, said that concentrations of metallic traffic particles were three higher on roads with speed bumps.
“Measures such as average speed checking rather than speed humps or pedestrian bridges rather than crossings would be helpful for this, especially in residential areas and near schools,” she said.
“Macrophages protect the lung from microbes and infections and regulate inflammation, but we found that when they’re exposed to brake dust they can no longer take up bacteria.
“Worryingly, this means that brake dust could be contributing to what I call ‘London throat’ – the constant foggy feeling and string of coughs and colds that city dwellers endure – and more serious infections like pneumonia or bronchitis which we already know to be influenced by diesel exhaust exposure.”
It is estimated that only seven per cent of particulate pollution in traffic comes from tail pipe exhaust fumes, with the rest comes from sources such as tyre, clutch and brake wear, as well road dust.