Only a few studies consider the increased ventilation rate associated with active modes. One study [22] showed that the minute ventilation rate (product of the breathing rate and the volume of air per breath) of cyclists was on average twice that of car commuters (an increase from 12 L min-1 to 24 L min-1 ) and two studies [21, 23] suggest 31 L min-1 , and 40-60 L min-1 for cyclists, respectively. No studies could be found specifically in relation to the exposure of commuters who run to work, though one would expect these to be comparable or higher than those of.
