Alternaria Mold in the Home Like its cousins cladosporium and penicillium, alternaria is one of the most common types of outdoor mold. There are more than 40 known species of this fungi, which is often responsible for leaf spots and degenerative diseases on trees and bushes.
Aspergillus species produce toxic compounds, the most well known being aflatoxins. Aflatoxin is a class 1 carcinogen produced by strains of Aspergillus flavus and Aspergillus parasiticus. The best known toxic metabolites of A. fumigatus are mainly fumigaclavines A, B, C, and D, spinulosin and tremorgenous toxins, e.g. verruculogen.
"Toxic mold" is a term that is used to describe types of mold that are considered deadly to humans. Most people believe that the name refers to one particular species of mold; however, it encompasses hundreds of species, a small fraction of which are not very harmful to the human body.
Presence of significant numbers of Aspergillus/Penicillium and unidentified spores (including ascospores and basidiospores) in the indoor environment is indicative of poor air quality. However, it’s difficult to tell from these results whether the indoor spores originated from outdoors and whether the spores belong to Aspergillus/Penicillium or other moulds with similar spores.