Composed of iron particles, brake dust is caused by friction between the iron brake rotor grinding on the brake pads when a vehicle slows down. This brake dust is then worn away and becomes airborne. And as recent research conducted by me and my colleagues found, brake dust triggers inflammation in the lung cells with the same severity as diesel particles.
By adding brake dust particles to macrophages – the cells responsible for clearing the lungs of invading germs, waste and debris – we saw a nearly 185% increase in the cell’s inflammatory activity. Not only that, we also found brake dust prevented the immune cells from destroying Staphylococcus aureus – a species of bacteria responsible for pneumonia. Once again, the brake dust was found to be as toxic as diesel particles.
This discovery might mean that pollution from brake dust might be contributing to the high numbers of chest infections and froggy “city throats” that are reported by people living and working in urban areas. However, because the isolated cells that we used in our experiments can act differently to cells found in a living human’s lungs, further research is needed to confirm whether particle exposure contributes to infection risk in people.