Biking for fresh air? Urban air quality not as good as we think

Credit TimKovach.comAs I have increased the number of miles I commute on my bike to more than 100 a week, I’m beginning to see the positive effects all this riding is having on my body. I’ve lost 10 pounds, my joints feel great and my metabolism has increased.

However, I have been pondering the possible downsides of biking in traffic. Not just safety concerns (getting squished). Many mornings I’ll get stuck behind cars at intersections that cough up a large amount of exhaust in my direction.

A blogger by the name of Tim Kovach wrote about the need for traffic planners to consider air quality when designing bike infrastructure. I found his post to be full of answers for what I had been concerned about.

On the one hand, cyclists help to improve both local and regional air quality, full stop. Bikes are emissions free and every mile spent cycling rather than driving keeps roughly one pound of carbon dioxide (CO2) out of the atmosphere. The more people who move out of cars and onto bikes, the more we can mitigate transportation-related air pollution (TRAP) and reduce everyone’s exposure to its harmful effects.

TRAP is a new term for me. According to the Union of Concerned Scientists: “The health risks of air pollution are serious. Poor air quality increases respiratory ailments like asthma and bronchitis, heightens the risk of life-threatening conditions like cancer, and burdens our health care system with substantial medical costs.”

Many cyclists ride to enjoy fresh air…and to not produce pollution.

Unlike cyclists, who have no air exchange buffer, drivers can roll up their windows and turn on recirculated air, lessening their personal exposure to TRAP, even as they produce it. Because cyclists spend more time on the road (due to their slower speeds) and breathe more heavily, they inhale higher levels of pollution in nearly every instance.

I go up and down a few of Richmond’s steep hills and they certainly leave me breathing heavily. Which can mean lots of polluted air getting sucked into my lungs, and not all of it is fresh.

Reducing the number of intersections a cyclist has to cross not only cuts his/her travel time, it also limits the number of idling vehicles s/he will face. And increasing the amount of vegetation between cars and cyclists can help slash pollution levels, as plants filter out a variety of air pollutants. According to the authors, a one unit increase in vegetative cover lowers black carbon and nitrogen dioxide levels by 3.4 percent and 11.6 percent, respectively.

Richmond loves trees, which helps. Concerned cyclists should consider changing to lower-trafficked, heavily vegetated routes whenever possible.

With all this in mind, the concept of “vulnerable road users” takes on a new meaning. Cyclists are not only at a greater risk of being injured or killed in a collision, we are also at a heightened risk of suffering the ill effects of TRAP. Planners must start taking this into account. Bike infrastructure that may make sense from a safety standpoint may not hold up when we account for air pollution.

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