Fig. 1.

Images of procedures being conducted in the laminar flow hood: (A) transferring samples from the original quartz fiber filters with distilled water, after which H₂O₂ is added to reach a concentration of 15 %; (B) air samples in 15 % H₂O₂ are left to react over the counter for a week, properly sealed with aluminum foil; (C) after a second transfer to a saturated solution of NaI, samples are shaken in the vortex for 1 min and left to settle for 90 min before being filtered; (D) glass fiber filter after being washed with NaI loses its integrity.