Airborne Mould Levels and Related Environmental Factors in Australian Houses

Airborne mould sampling studies were conducted in 40 selected Australian (Latrobe Valley, Victoria) houses. Both total indoor culturable and total mould spore levels were observed to be relatively high with 58% of houses with one or more rooms exceeding 1,000 cfu/m3 and 48% exceeding 10,000 spores/m³, respectively. Median indoor total mould spore levels exceeded total culturable levels by 14-fold in concurrent sampling. An evaluation of the indoor/outdoor ratios of selected genera indicated that 50% of indoor concen trations could be explained by outdoor mould levels. Applying a univariate analysis of variance, significant differences in mould levels associated with a variety of housing characteristics and environmental factors were observed. A house age >20 years and relative humidity ≥ 70% were observed to be signifi cant independent contributing factors to elevated indoor culturable mould levels while similarly these factors with water intrusion through the building envelope gave elevated total indoor mould spore levels.