Commuters who regularly cycle through major cities like London every day inhale more carbon than pedestrians, and this may cause damage to their lungs, according to new research from the UK that was presented on Sunday at the European Respiratory Society’s Annual Congress in Amsterdam. The researchers say planners should think about this when devising city cycling routes.
Because of fossil fuel combustion, there are large amounts of black carbon particles (soot) in the air, which can end up in people’s lungs when they breathe it in.
More and more studies are showing that inhaling black carbon particles can affect health and lead to heart attacks and reduced lung function.
Professor Jonathan Grigg from Barts and the London School of Medicine and colleagues wanted to test the idea that the way a person commutes to work in a large city affects their exposure to black carbon; more specifically that a cyclist has a higher personal exposure than a pedestrian.
To test their hypothesis, they compared the lung dose of black carbon in healthy volunteers by sampling their airway macrophages – immune system cells that sit on the surfaces of the lower airways and ingest foreign substances.
The volunteers, all regular urban commuters, were five healthy cyclists that regularly used their bikes to get to work in London and five healthy pedestrians. None of them were smokers, and their ages ranged from 18 to 40 years.
They gave sputum samples from which the researchers were able to test the amount of black carbon in their airway macrophages.
Although only a small sample, the results showed that the cyclists had 2.3 times more black carbon in their lungs than the pedestrians. The results were statistically significant (the probability that this finding would occur by chance was less than 1 in 100).
One of Grigg’s colleagues on the study, Dr Chinedu Nwokoro, an active cyclist who also works in London, said:
“The results of this study have shown that cycling in a large European city increases exposure to black carbon.”
Nwokoro said this could be due a number of reasons, such as cyclists breathe faster and more deeply than pedestrians and do this while being much closer to the exhaust fumes of cars and other road vehicles.
“Our data strongly suggest that personal exposure to black carbon should be considered when planning cycling routes,” said Nwokoro, who also pointed out:
“Whether cycling by healthy individuals is in itself associated with adverse health effects is currently being assessed in a larger ongoing study.”
Written by Catharine Paddock PhD