Mold

Mold is a common term for a large family of fungi that have a cottony or wooly appearance. There are nearly a million species of mold. Mold is a naturally occurring organism that has been around far longer than us. Mold grows in buildings where there is moisture, air, a food source, and when the temperature is between 40 and 140 degrees F. When conditions for growth are not met, mold becomes dormant; it does not die. Mold spreads by dispersing spores through the air as well as by growth on or within building materials.

People sometimes tell us that they don't have mold in their homes. We ask what happens if they leave bread in a drawer for a month or don't take out the garbage for two weeks. This helps them understand that no matter how clean they keep their home, mold spores are always there ready to grow on any favorable host. There are always mold spores in the air and there is always some mold in buildings, so having an objective of a "mold-free home" is not realistic. 

Since it is normal for mold to be present in the air and thus to be found in buildings, it's mere existence is not necessarily a reason for alarm. But if mold is present in indoor levels higher than would be found in outdoor air, or if a significant mold colony is growing on building surfaces or in building walls or ceilings, it could be a cause for concern. 

• Some mold is harmless, a cosmetic nuisance.
• Some mold is allergenic to some people, in much the same way some people are allergic to peanut butter or shellfish. 
• Toxic mold is dangerous for everyone; young people, old people, and people with respiratory problems or compromised immune systems are the most vulnerable.

Media articles about "black mold," especially Stachybotrys, have terrified some people. Actually, it is common to find black Stachybotrys chartarum in small amounts in houses where there has been leakage or water entry. It is a toxic mold and it should be removed. But don't assume that anything black on the wall or ceiling is highly toxic mold. Other common black species may be of low or no toxicity. People may react to mold spores alone. There does not always have to be a visible growth to cause problems for sensitive people.

You cannot tell what kind of mold you are dealing with by looking at it. Competent identification is important. An expert, trained in microscopic identification of a cultured sample of mold, can usually determine it's identity. It is not reliable to judge with the naked eye, or on mold color. 

Although mold is needed and always with us, we want to keep mold in it's place, preferably outdoors. While we will always have some spores in our homes, the goal is to keep the spores from growing to problem levels.