Bicyclists may be inhaling twice as much soot as pedestrians

You’ve decided to help your health and the environment by riding your bike to work. Good for you! Sorry to have to deliver the bad news: you may be inhaling more soot.

The amount might be more than twice as much as urban pedestrians, says a pilot study presented Sunday at the European Respiratory Society’s Annual Congress. The study involved five cyclists who regularly biked to work and five pedestrians from London. They ranged in age from 18 to 40 and were healthy nonsmokers.

Researchers analyzed airway microphage cells from the participants’ sputum samples. Airway microphage cells guard the body against foreign bodies such as viruses and bacteria. The cyclists were found to have 2.3 times the amount of black carbon in their lungs compared with the pedestrians.

“The results of this study have shown that cycling in a large European city increases exposure to black carbon,” said co-author Chinedu Nwokoro in a news release. “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.”

Other studies have weighed the health risks and benefits of urban cycling; one 2010 study in the journal Environmental Health Perspectives looked at what might happen if 500,000 people in the Netherlands traded their cars for bicycles for short daily trips, and measured the outcome in life-years gained or lost.

By increasing their exercise, bike riders would gain three to 14 months of life. The possible effect on mortality would mean 0.8 to 40 days lost from inhaling more air pollution, and five to nine days off from the hike in traffic accidents. Advantage: cycling.

A similar 2011 study in the British Medical Journal looked at the effects of bike sharing on health and the environment. They found that while there could be a yearly jump of 0.13 deaths from air pollution annually compared with drivers, 12.28 deaths could be avoided each year due to the health advantages from biking.

And a study looking at how transportation methods affected commuters’ exposure to air pollution found cyclists may be at risk. The 2010 study in Environmental Health Perspectives examined particulate matter and soot along two bike routes with different amounts of traffic in the Netherlands.

Because cyclists took in volumes of air per minute that were twice as high as people in cars and buses, researchers estimated their inhaled air pollution amounts were highest.

If you commute via bicycle to work or even use your bike for short trips around town, do you use any type of mask or filter? If so, do you think it’s made a difference? Tell us about it.