were sampled using double sided tape on an electron microscope stub (1.27 mm
diameter) every 24 h for 9 days as was carried out in the preliminary
experiment (reported by Morgan et al. [1]). This was undertaken in
order to establish whether or not similar trends could be identified in
the different rooms. For the final two runs the sampling time frame
was extended so that the 22 sites were sampled every 48 h for
17 days. The flowers were then removed (after 9 days for runs 1–4
and after 17 days for runs 5–6) and the sites within the room were
sampled every 5 days for the next 20 days for runs 3–6. At the end of
each experimental run, the room was thoroughly cleaned and control
samples were taken to establish the cleanliness of the room for subsequent runs.