The mold types you describe (Cladosporium, Aspergillus and Penicillium) are very common in airborne samples collected in buildings. Cladosporium is the most abundant mold type found in samples collected on indoor and outdoor samples. It is a ubiquitous organism. Like most fungal species humans may become sensitized to it and develop allergy symptoms which in some individuals may develop into asthma. Cladosporium is the most common of the so-called black molds. It produces a black pigment that protects it from ultraviolet light. This characteristic as well as its growth and dispersal characteristics is likely responsible for its presence and abundance in the environment. It produces no major mycotoxins of concern.

Because Cladosporium is often more abundant outdoors than indoors, care must be taken to interpret mold-sampling results correctly. The presence of high indoor concentrations of Cladosporium may indicate that it is coming in from the outside through open windows or doors.

Test results you report also indicate the presence of Aspergillus and Penicillium. Both mold types are more commonly detected in indoor (than outdoor) samples. As such, it appears that your building in fact has a mold infestation problem.

Both Aspergillus and Penicillium cause sensitization reactions in sensitive individuals that can cause chronic allergy symptoms, and as indicated above, asthma in some individuals. Among these, Aspergillus is of the greatest health concern. There are approximately a half dozen or more species of Aspergillus that can be easily identified. Several of these A. flavus and A.versicolor produces potent mycotoxins. A.flavus produces aflatoxin, a not uncommon contaminant of grains such as corn and legumes like peanuts (and peanut butter). Exposure to very higher aflatoxin levels has been reported to cause liver toxicity and liver cancer. Exposure to A. flavus spores by archaeologists and staff is believed to have been responsible for the deaths that have been ascribed to King Tut's curse. Fortunately, such exposures are not likely to occur in most mold-infested buildings. A. fumigatus commonly found growing in compost and not uncommonly found in building dust is of particular concern to immune-compromised individuals who it readily infects and causes a life-threatening disease of the lungs.

None of these mold types have any direct relationship to Stachybotrys. Both Stachybotrys and Cladosporium produce black pigments. As such, it is difficult to distinguish between them without microscopic evaluation when "black mold" is observed growing on ceiling tile or other building surfaces. In most cases "black mold" is dominated by Cladosporium , a mold type that is of considerably less health concern than Stachybotrys.