Lungs of cyclists may be sootier

PEOPLE WHO cycle through London and other major cities have higher levels of black carbon in their airway cells than those who walk to work, research published yesterday suggests.

Black carbon particles (soot) are known to cause lung and heart damage. The small preliminary study involving five commuting cyclists and five pedestrians was carried out by researchers from St Bartholomew’s Hospital and the London School of Medicine. They took samples of cells from the participants’ lower airways. These cells, called macrophages, sit on the surface of the airway ingesting foreign material such as black carbon, a byproduct of exhaust.

The research presented at the European Respiratory Society’s Annual Congress in Amsterdam, suggests that cyclists inhale more black carbon than pedestrians. In this small study, cyclists had 2.3 times more black carbon in their lungs compared with pedestrians

Combustion of fossil fuels results in large numbers of inhalable particles of soot. There is increasing evidence inhalation of black carbon particles is associated with a wide range of health effects – including heart attacks and reduced lung function.

The researchers collected sputum samples from five adults who regularly cycled to work and five pedestrians, and analysed the black carbon found in their macrophages. All participants were non-smoking, healthy urban commuters aged 18-40.

Dr Chinedu Nwokoro, one of the researchers, said: “The results of this study have shown that cycling in a large European city increases exposure to black carbon. This could be due to a number of factors, including the fact that cyclists breathe more deeply and at a quicker rate than pedestrians while in closer proximity to exhaust fumes.”