City cyclists inhale double the soot, research says.
London cyclists inhale more than double the amount of black carbon, or soot, than pedestrians, research suggests.
The study by Prof Jonathan Grigg from Barts and the London School of Medicine, showed the cyclists had 2.3 times more inhaled soot than walkers.
Evidence suggests breathing in black carbon could lead to heart problems and reduced lung function.
The findings are to be presented to the European Respiratory Society's annual congress in Amsterdam.
In the study, researchers tested five adults who regularly cycled to work in London, and five pedestrians for inhaled soot particles, which are created by motor vehicle exhausts.
All participants in the study were non-smoking, healthy commuters aged between 18 and 40.
Dr Chinedu Nwokoro, one of the researchers of the study and an active cyclist, 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, which could increase the number of airborne particles penetrating the lungs.
"Our data strongly suggest that personal exposure to black carbon should be considered when planning cycling routes.
"Whether cycling by healthy individuals is in itself associated with adverse health effects is currently being assessed in a larger ongoing study."