Distribution of Indoor Fungal Spore Levels

Minati Dhar, Freddy Pacheco, Jay M. Portnoy, Charles S. Barnes



The subject of airborne fungal spore levels in home living spaces has been of considerable interest to the Allergy community. To study the distribution of fungal spores in typical domestic indoor spaces we conducted the following studies.


Data for indoor spore levels from two Healthy Homes Demonstration projects was combined to produce a large database. Airborne indoor fungal spore collections were routinely taken from bedrooms. bathrooms, main living areas, kitchens, basements and outdoors using either an Allergenco or a Bioaire spore trap. Collections were evaluated microscopically for 25 common indoor spore types. Statistical evaluation of results was carried out using SPSS software.


The database contained data from 1055 separate collections taken in 250 individual homes. Mean total spore level for all collections was 4383 per cubic meter of air(M3). The lowest quartile count was 0 to 213 spores /M3 and the highest Quartile was 2128 to 550,395 spores /M3. The highest level recorded was 550,385 spores/M3 and the top 5% of counts were above 10072 spores/M3. Cladosporium appeared most frequently (97%) of collections (median 171 spores/M3) but Aspergillus/Penicillium type spores had the highest mean presence with 2540 spores/M3. Stachybotrys spores were identified in 10% of collections and Aspergillus/Penicillium spores in 40% of collections. The highest spore levels were found in basements (mean 14,030 spores/M3) and the lowest in living/family rooms (mean 1639 spores/M3).


Domestic airborne fungal spore levels are typically in the low thousands of spores/M3 with a few contaminated areas exceeding hundreds of thousands of spores/M3.


Journal of Allergy and Clinical Immunology, Vol. 131, Issue 2, AB80

abstract No: 

    • AAAAI 2013 (69th)