The incidence of moulds within 525 dwellings in the United Kingdom

Airborne viable mould spore counts were determined for living rooms, kitchens and bedrooms within 503 council houses in Edinburgh and Glasgow (UK); at least one child lived in each house. Approximately one‐half of the 1709 rooms sampled contained <100 colony forming units (cfu) m^‐3 of air, with a maximum count in excess of 21,000 cfu m^‐3. Large variations often occurred, even between rooms in the same dwelling. Where visible surface mould growth occurred, in 49% of such rooms the airborne spore count was >300 cfu m^‐3, indicating a positive relationship between surface growth and air spore levels. The most common genera isolated from internal surfaces (including those from a further 22 London houses) were identified.