Fig. 1

Estimated ventilation rates by building and vehicle type. The central line indicates the median, the box range the interquartile range (IQR), the whiskers the most extreme value within 1.5 * IQR from the box, and the points outlying values. The n’s indicate the number of collection days (buildings) or journeys (transport) One outlier point for a church (estimated ventilation rate of 5374 ls^− 1) is not included in the figure