What is Mold?

Mold is a part of the fungi kingdom. Other types of fungi include yeast, mildew, truffles, puffballs, and mushrooms. This is a classification completely separate from plants and animals. Whereas plants can make their own food through carbon dioxide, fungi and animals feed on complex carbons found in living organisms. Fungi do this by excreting enzymes that break down those organisms, so that they are then able to ingest them. This is in contrast to the process of how animals get their nourishment, which is by ingesting food and then degrading it internally.

There are hundreds of thousands of species of fungi and they are not always something you want to get rid of. Fungi play the important role of breaking down dead materials in the environment, such as trees, insects, and animal carcasses.

What Mold Needs to Grow

The two things that mold needs to grow are moisture and food. Moisture is the most important factor, because mold spores can exist indoors and not cause problems at all until a little water comes along. And it does not need much moisture at all. A little condensation after a shower in the bathroom or a pipe leak under the kitchen sink can be enough for mold to germinate.

Other common sources for moisture include high indoor relative humidity levels, roof leaks, sprinkler systems, floods, and humidifiers. Experts assert that indoor relative humidity levels should remain between 40 and 60 percent in the home to avoid mold growth. If you control the moisture in your home, then you can control mold growth.

After water, mold needs nourishment to grow. Mold gets food from the surfaces it plants itself on. It can grow on virtually any surface including wallpaper, textiles, wood, plants, soil, and tile. Mold can even grow on dirt or dust, which means that any surface that can get dirty or collect dust can collect mold. This opens up the floodgates as far as surface growth opportunities go.

Although the majority of molds grow best between 40 and 100 degrees fahrenheit, there are types of mold that grow well in extreme cold as well as extreme heat.

Common Indoor Molds

The five most common indoor molds are Penicillium, Alternaria, Aspergillus, Cladosporium, and Stachybotrys. Here is a little more information on each.

Penicillium
Penicillium is the most common indoor mold. It got its name from the latin word penicillus which means paint brush, because of its long tentacle-looking structures that resemble a paint brush. There have been about 200 species of Penicillium discovered.

This type of mold causes food spoilage, particularly in fruits and vegetables. It usually takes on a blue, green, or yellow form and it is often referred to as the color of spores it produces. In other words, someone might call this “green mold” rather than Penicillium.

Penicillium mold spores can cause allergic reactions in people exposed to them. Some species have been known to produce toxic compounds, or mycotoxins, which means those living in a home with a significant amount of this type of mold could have their health compromised. The individuals who are particularly vulnerable are infants, elderly, and those with weakened immune systems.
Alternaria
Alternaria (Alternaria alternata) is another common indoor mold that is also one of the most allergenic and a risk factor for asthma. This kind typically develops in a black to grey color with a suede-like appearance. The optimal temperature for this type of mold to grow is in between 77 and 82 degrees fahrenheit and its spores can be detected from Spring through Fall.

All mold requires moisture to grow, but what is worrisome about Alternaria is that it does not require much water to spread at a rapid rate. It can grow on almost any surface indoors and it can be found on soil, vegetation, and sewage outdoors. It has been known to cause health issues for those exposed to it.
Aspergillus
Aspergillus appears both indoors or outdoors, as do all of the molds mentioned here. This type of mold thrives on organic materials and can be commonly found in soil, dead plant parts, and compost piles. The optimal growth temperature for this mold is 98.6 degrees fahrenheit, commonly known as body temperature.

Sometimes the inhalation of Aspergillus spores does not cause a health problem for people, but it has been known to cause an infection known as Aspergillosis in those with weakened immune systems. Other issues it has been linked to include respiratory problems, hay fever, asthma, skin and eye irritation, and Farmer’s lung. There are about 190 species of Aspergillus known today, but only about a fifth of those have been connected to health problems for human beings.
Cladosporium
There are over 40 species of Cladosporium, another common mold type. Indoors, thismold can be found growing on fabric, wood, tile, carpet, wallpaper, and many other cellulose surfaces. Outdoors, it is commonly found in soil and dying plants. Exposure to this type of mold has led to asthma, hay fever, hypersensitivity to mold, as well as infections of the skin, eyes, and sinuses.
Stachybotrys
Stachybotrys chartarum, which is also known as Stachybotrys atra, is another type of indoor mold that can grow on almost any material, particularly those high in cellulose. It is greenish-black in color. This kind of mold has been known to release mycotoxins as well.

There has been speculation that Stachybotrys chartarum was linked to pulmonary hemorrhage among infants in areas of Cleveland, Ohio, but the Center for Disease Control and Prevention (CDC) did not find such a link in their research.

You Cannot Completely Eliminate Mold Spores

Mold spores are everywhere, including inside of your home. It is actually normal for mold counts outdoors to match mold counts indoors. It is when mold counts in your home are higher than outside your home that you need to worry, because that likely means that the mold inside found a water source. Mold spores will not grow if water is not present. But once moisture is introduced, they can spread at a rapid rate and produce spreadable spores in as little as 24 hours.