Table 1Moisture levels required for growth of selected microorganisms in construction, finishing and furnishing materials

Moisture levelCategory of microorganism
High (aw, > 0.90; ERH, > 90%)Tertiary colonizers (hydrophilic)
Alternaria alternata
Aspergillus fumigatus
Epicoccum spp.
Exophiala spp.
Fusarium moniliforme
Mucor plumbeus
Phoma herbarum
Phialophora spp.
Rhizopus spp.
Stachybotrys chartarum (S. atra)
Trichoderma spp.
Ulocladium consortiale
Rhodotorula spp.
Sporobolomyces spp.
Actinobacteria (or Actinomycetes)
Intermediate (aw, 0.80–0.90; ERH, 80–90%)Secondary colonizers
Aspergillus flavus
Aspergillus versicolora
Cladosporium cladosporioides
Cladosporium herbarum
Cladosporium sphaerospermum
Mucor circinelloides
Rhizopus oryzae
Low (aw, < 0.80; ERH, < 80%)Primary colonizers (xerophilic)
Alternaria citri
Aspergillus (Eurotium) amstelodami
Aspergillus candidus
Aspergillus (Eurotium) glaucus
Aspergillus niger
Aspergillus penicillioides
Aspergillus (Eurotium) repens
Aspergillus restrictus
Aspergillus versicolorb
Paecilomyces variotii
Penicillium aurantiogriseum
Penicillium brevicompactum
Penicillium chrysogenum
Penicillium commune
Penicillium expansum
Penicillium griseofulvum
Wallemia sebi

Note. aw, water activity; ERH, equilibrium relative humidity


at 12 °C;


at 25 °C

From: 2, Building dampness and its effect on indoor exposure to biological and non-biological pollutants

Cover of WHO Guidelines for Indoor Air Quality
WHO Guidelines for Indoor Air Quality: Dampness and Mould.
Copyright © 2009, World Health Organization.

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