Interpretation of Sampling Results
The outdoor sample establishes a baseline for comparative evaluation of the indoor air samples. Because there are no federal standards for mold spore count levels in indoor environment. It is important to interpretate indoor and outdoor relationships by individual spore types and levels detected in different environments. Usual comparisons are indoors to outdoors or complaint areas to non-complaint areas. Specifically, in buildings without mold problems, the qualitative diversity (types) of airborne fungi indoors and outdoors should be similar. However, in problem buildings where there is fungal contamination, one or two spore types may dominate the air samples. Often these are not present in the outdoor air or present in low concentrations, may indicate a moisture problem and the indoor air quality is considered to be degraded.
Also, the consistent presence of certain fungi such as Stachybotrys chartarum, Aspergillus versicolor or various Penicillium species over and beyond background concentrations may indicate the occurrence of a moisture problem and a potential atypical exposure and it needs additional investigation, supplemental testing or corrective measures. Generally, indoor mold types should be similar and levels should be no greater than outdoor and/or non-complaint areas. Analytical results from bulk material or dust samples may also be compared to results of similar samples collected from reasonable comparison areas.
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