Monday, March 18, 2013

Bicycle Boulevards for Cleaner Air

Cyclist route choice, traffic-related air pollution, and lung function: a scripted exposure study(24 page pdf, Sarah Jarjour, Michael Jerrett, Dane Westerdahl, Audrey Nazelle, Cooper Hanning, Laura Daly, Jonah Lipsitt, John Balmes , Environmental Health, Feb. 7, 2013)

Today we review research on the exposure of cyclists to pollution while commuting on urban streets in Berkeley, California. Comparisons were made between conditions on special cyclist routes along low traffic corridors – bicycle boulevards- with those on major roadways. Results indicate significantly lower exposure while on roads with low traffic and outside of rush hours. bike emissions  

Key Quotes:

“In the United States, cycling accounts for less than 1% of trips”

“While measured concentrations of PM2.5, elemental carbon, and ultrafine particulate matter are similar or higher inside vehicles than on bicycles, cyclists’ minute ventilation has been recorded at two to four times that of car passengers”

 “the Berkeley Bicycle Plan, which established a network of seven bicycle boulevards: low-volume residential streets with signs, pavement markings, and traffic calming devices designed to promote safe and convenient bicycle commuting and walking.. the Berkeley Bicycle Plan deemed streets with low traffic volumes, defined as less than 3,000-4,000 vehicles per day, as appropriate for bicycle boulevards.”

 “We found significantly elevated concentrations of ultrafine particulate matter and carbon monoxide, and borderline significant differences for black carbon on the high-traffic route relative to the low-traffic route..we also found that spikes in pollutant concentrations occurred mainly at intersections and busy streets or truck routes.”

“avoiding rush-hour periods significantly reduces cyclists’ pollution exposure”

“Lower pollutant exposures associated with low-traffic routes and bicycle boulevards may support future changes to the built environment (city, building, and street design) that allow for healthier and safer routes for active transportation.”
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