Group riding: Cyclists exposure to road vehicle emissions in urban environments

A series of wind tunnel experiments were conducted in the University Surrey’s Environmental Flow with a 1:50 scale typical London street canyon to assess exposure cyclists riding group emissions polluting vehicles. propane source emitted from an Ahmed body was used model car exhaust and fast flame ionisation detector measure pollutant concentration around four for multiple configurations source, cyclists, directions. Two cases investigated vehicle driving front line adjacent them (as if it overtaking them). In first case, small incidence, findings confirm that decreases exponentially their distance dependence on direction but largely independently riders position within group. For large incidences, urban canyons, rider becomes more important. second set experiments, positioned riders, found be preferable regardless as this results lower pollutants. This is likely linked complex aerodynamic field generated by can trap fumes amongst hence increasing exposure. research suggests should considered when designing mitigation strategies minimise road traffic pollution environments, where busy narrow cycle lanes often line.