A number of moulds are frequently found in carpet and mattress dust. Eurotium repens is the most frequently detected mould in mattress dust. Others include Aureobasidium pullulans, Alternaria alternata, Penicillium chrysogenum, Aspergillus penicilloides and Aspergillus restrictus.

More than 100 species of moulds have been recorded from carpet dust. As with mattress dust, the most frequently isolated mould in carpet dust is Eurotium repens. The others are Penicillium chrysogenum, Alternaria alternata, Aureobasidium pullulans and Phoma herbarum.

Concentrations of these moulds in carpet and mattress dust can be as high as 70 million colony forming units per gram of dust. Such high concentrations of moulds are likely to cause respiratory allergy or irritating symptoms. Therefore, it is import to regularly HEPA vacuum the carpets, mattresses and upholstered furniture to reduce the dust and spore concentration. If people are suffering from reoccurring respiratory allergy or irritating symptoms in a building where there is no visible mould, it is suggested that dust be tested for the types and concentrations of mould present.