Sampling was conducted by using the one-stage microbial air sampler MAS 100 (Merck, Darmstadt, Germany) operating with a flow rate of 100 L min1. The cut-off-size of the MAS-100 sampler (d50 ¼ 1.7 mm) is adapted to collect airborne fungal spores with an aerodynamic diameter of 2 mm (Yao and Mainelis, 2006). Airborne xerophilic fungi were collected on Dichloran Glycerol Agar (DG18) and aerobic mesophilic bacteria on Tryptic Soy Agar (TSA). The concentrations of microorganisms were indicated in cfu m3 (¼colony forming units per m3 air).