The thousands of rush hour cars and trucks generate huge quantities of inhalable particles of soot and there is increasing evidence that inhalation of these black carbon particles is associated with a wide range of health effects, including heart attacks and reduced lung function.
A team from Barts and the London School of Medicine wanted to test the idea that the way a person commutes to work in a large city affects their exposure to black carbon and more specifically, that a cyclist has a higher personal exposure than a pedestrian.
To test this theory the study compared the levels of soot in a lower airway cell called the airway macrophage – a specialised cell that sits on the airway surface and ingests foreign material.
The study of healthy, non-smoking cyclists and pedestrians revealed that the cyclists had 2.3-times more black carbon in their lungs than the pedestrians. The probability that this difference occurred by chance is less than 1 in 100.
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.
The data strongly suggests that personal exposure to black carbon should be taken into consideration when planning cycling routes.
Source: European Respiratory Society