Fig. 1

WHO cone bioassays conducted using bioassay board configurations ‘with holes’ and ‘without holes’ sections. Panel A: Four WHO cones were placed on a net, which is placed over the ‘holes’ or over an A4 sheet of paper (‘no holes’). Four cones on each net sample (replicates 1–4). Panel B: The board assembly was placed against the wall at an angle of 45°