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Original Article


Guidelines on Ambient Intramural Airborne Fungal Spores


A Fairs1, AJ Wardlaw1, JR Thompson,2 CH Pashley1

1Aerobiology Unit, Institute for Lung Health, Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
2Centre for Biostatistics and Genetic Epidemiology, Department of Health Sciences, University of Leicester, Leicester, United Kingdom

J Investig Allergol Clin Immunol 2010; Vol. 20(6): 490-498



Objectives: To generate baseline data for indoor airborne fungal spores in noncomplaint residential properties (with no moisture/moldrelated problems) and to identify home characteristics indicative of elevated fungal levels.

Methods: Air samples were collected onto petroleum jelly–coated slides from living rooms of 100 residential properties in Leicestershire, United Kingdom, using a Burkard continuous recording air sampler. The slides were examined by microscopy to determine fungal spore concentrations (spores/m3 air/day).

Results: Total indoor fungal spore concentrations were approximately 16% of outdoor concentrations. Abundant indoor fungal genera include Cladosporium, Sporobolomyces, Tilletiopsis, and Didymella, all of which followed seasonal patterns of release and detection. No clear association was shown between outdoor-predominant fungi and home characteristics. In contrast, Aspergillus/Penicillium-type (Asp/Pen-type) spores were common indoors and exceeded outdoor levels, with the highest concentrations detected in properties over 90 years old (P=.006) and terraced properties (P=.003).

Conclusion: Asp/Pen-type spores are found in noncomplaint UK residential properties and mostly in old terraced houses. This study provides guidelines on acceptable levels of Asp/Pen-type spores and other abundant indoor fungal taxa that can be comparatively used in clinical evaluations of fungal exposure–related disease.

Key words: Mold/mould. Fungal spores. Environmental exposure. Reference values. Aerobiology