We also find that a minority of participants emitted substantially more aerosols than others, sometimes more than an order of magnitude above the median, consistent with the long-tail of a log-normal distribution when viewed in linear-concentration space. This observation is consistent with a previous study. However, the highest emitters were not consistently the highest across all activities, suggesting the magnitude of emission from an individual may be highly activity specific. It is unclear why some participants emit substantially more than others, and further studies are required to better characterise the variability of aerosol emission across the population, as well as the consistency of emission from an individual over time.