How to Breathe Cleaner Air While Biking: Ride at 11 MPH
Portland State University Ph.D candidate Alex Bigazzi has been biking around Portland with a $300 homebuilt air quality monitor. His goal: to get a sense of how much pollution he was breathing and how to minimize exposure to harmful fumes. Bigazzi has recently been sharing his findings around Portland.
Michael Andersen at Bike Portland reports today that Bigazzi's first tip is to not ride very fast:
The biggest contributor to pollution intake, Bigazzi found, isn’t actually how dirty the air around you is. It’s how much of it you breathe.
“Ventilation completely dominates the exposure differences,” Bigazzi said. “The exposure differences are not that big.”
That creates an interesting mathematical puzzle: the harder your body works, the more pollution you breathe in. But the faster you move, the less time you’ll spend in the dirty air.
So assuming you’re headed to a place where the air is cleaner than it is along a roadway (Precision Castparts commuters, take note), here’s a curve Bigazzi constructed that shows the optimum speed to ride for various bikeway slopes. It’s expressed in kilometers per hour; the 17.5 kph “minimum ventilation speed” for a flat 0 percent grade is 11 mph.
That doesn't mean street-level air quality isn't important too:
Based on these calculations and Bigazzi’s hard data, he found that biking along a major arterial like Powell Boulevard means ingesting three to five times more traffic-related pollutants than biking on a local street.
There’s been some study of pollution levels in protected bike lanes, Bigazzi said, and pollution exposure there seems to be “measurably lower than where a bike lane would be on the same facilities for traffic-related air pollution.” He said he didn’t have exact numbers on this phenomenon.
Finally, Bigazzi and Bike Portland offer a reminder that, regardless of speed or street type, the health benefits of biking outweigh the costs by orders of magnitude.
Elsewhere on the Network today: Chuck Marohn at Strong Towns refines his argument that raising the gas tax won't help reform car-centric transportation policy. Mobilizing the Region explains how land banking can help facilitate equitable transit-oriented development. And Better Institutions says Denver's terrible highway expansion project probably would have been even worse if it was planned back in the 80s.
Stay in touch
Sign up for our free newsletter
More from Streetsblog USA
Talking Headways Podcast: Beyond Greenways
This week we’re joined by Bob Searns to talk about his new book and grand ideas for walking trails that circle whole regions and more local routes that make up a new mode of green infrastructure in cities.
Thursday’s Headlines Are Inside Out
Cars and trucks are getting safer for drivers and passengers, but people outside the vehicles are increasingly in danger.
New Federal Committee Will Push for Transportation Equity By Helping DOT Reckon With Its Past
“No one alive today is necessarily responsible for the origins of the [transportation] inequities that we inherited. But everybody who was alive today and in a position of responsibility, is accountable for what we do about it. That's why we're here.”
Report: America’s Historic Bike Boom is Flatlining
"This growth won't continue forever without being facilitated by more infrastructure investment, [and particularly] safety infrastructure."
SF Advocates Explore How Enhancing Disability Access on Transit Helps for Everyone
BART was the first accessible transit system in the country. Advocates want Bay Area transit agencies to do better at keeping buses and trains accessible for all.
