What is Mold?

In the broadest sense of the word, a mold is any organism that falls into the kingdom Fungi. Like plants, they usually are immobile, “taking root” on a surface; unlike plants, they are almost always saprophytic, feeding on dead organic matter instead of producing energy through photosynthesis.

Mold is a part of everyday life. Without it, we would be without food products such as cheese, beer, wine, even bread. Cycles of growth and decomposition would literally stop. Because fungi break organic matter into nutrients that can be absorbed into the root systems of plants, absence of these molds would halt the growth of most of the world’s ecosystems.

At this time there are more than 100,000 mold species classified, and they live almost everywhere in the world. Some mycologists speculate that as many as several hundred thousand species are yet to be identified. The worlds of indoor air quality and mold remediation take into account about three hundred relevant species of mold.

Molds reproduce by means of spores. These spores may be thought of as microscopic seeds. They are usually released after a disturbance and carried through the air to germinate in a new location. A very few species mechanically disperse their own spores. Every breath inhaled into the lungs contains a small number of mold spores. Storage and transportation alone allow for the settling of spores on building materials. Hyphae, the thin filaments that make up a visible mass of mold, are easily broken and released into the air.