Measurements of Airborne Fungal and Endotoxin Levels in Water-Damaged Buildings

Airborne fungi are often collected during the assessment of water-damaged buildings. Air sampling for endotoxin, a characteristic group of constituents of outer membranes of gram-negative bacteria, is another approach commonly used to characterize microbial conditions in buildings. This study presents results of fungal and endotoxin air samples collected in buildings with microbial complaints. Airborne fungal and endotoxin samples were collected from 11 buildings, including office buildings and residences, between November 1999 and March 2000. One building that did not have water damage history was used as a reference. Two indoor locations and one outdoor location were sampled for each building. The fungal and endotoxin levels outdoors were well correlated with a correlation coefficient of 0.91. All, except one outdoor sample, yielded endotoxin levels less than 1 EU/m3. An analysis of the association between water damage conditions with the detected total fungal, Penicillium, and endotoxin levels was performed. The results suggest that a combination of fungal and endotoxin air sampling is a useful tool in evaluating microbiological contamination in most water-damaged buildings selected in this study. For a more comprehensive assessment for microbial contaminations in buildings, air sampling for fungi and endotoxin as well as other sampling strategies are recommended.