Fig 1. Images of the sampler and disk as used for particle collection.

(A) The sampler as worn on shoulder strap of a small backpack containing the airpump; the arrow indicates the location of the time-lapse camera. (B) Close-up of the sampler; the arrow indicates the inlet. (C) An adhesive disk following collection for approximately 11.5 hours. The large arrows indicate the green and red powder used to mark the start and stop of sampling and smaller white arrows indicate visible bands of dust particles impacted during periods of high exposure. The numbers on the inner face are used to visually check the process during sampling.