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Mold Types and Causes

Toxic mold is an increasingly common problem in homes and commercial buildings. While many people have heard of toxic "black mold," harmful molds exist in a wide variety of forms. Depending on the individual who has been exposed, mold exposure may cause ill effects that range from very serious health problems to minor annoyances.

This article provides an overview of the main types of mold and common factors that cause mold in homes and commercial buildings.

Types of Mold

Mold performs the natural function of breaking down biological materials. Found almost everywhere in our environment, mold travels as tiny spores that are often light enough to float through the air. Mold spores may also stick to pets and humans. When mold spores come to rest on a damp area, they begin to grow and digest the material on which they have landed.

There are many types of mold -- some sources say that there are over 100,000 different species. Some mold species are considered harmless, while others can cause potentially serious health effects.

The most common mold types found in homes and commercial buildings are:

  • Cladosporium
  • Penicillium
  • Aspergillus
  • Alternaria, and
  • Stachybotrys chartarum (atra)

Molds may produce volatile organic compounds ("VOCs") or mycotoxins as byproducts of their metabolism. VOCs generally evaporate at room temperature. In fact, when a person smells a "musty" odor, he or she is actually smelling volatile organic compounds. Some VOCs produce adverse health effects, but generally, they are not extremely dangerous. In contrast to VOCs, toxins do not evaporate easily, and some are considered very dangerous to humans.

In the end, regardless of whether a particular type of mold produces VOCs or toxins, all molds should be considered potential health risks, and the presence of mold should lead to an investigation, clean up, and/or removal.

What Causes Mold in Homes?

Mold spores may enter your home through windows or open doors, and can be brought into the home after attaching to people and pets. In order for a mold spore to grow in indoor environments, there must be (1) abundant moisture, (2) the correct temperature range, and (3) a food source.

Sources of Moisture. Moisture can come from a variety of sources. Many modern homes and buildings are constructed in a very air-tight manner. While this is great for insulation purposes, it reduces the building's ability to "breathe" -- lessening the potential drying effects of natural air circulation.

Moisture may enter a building as a result of water damage from flooding, through broken pipes, as a result of excessive rain, or a malfunctioning air conditioner. Moisture in a home or building may soak carpeting and other materials, creating a moist food source on which mold may attach and grow.

Moisture may also enter a building through walls and living spaces by way of leaks in the roof, walls, or windows. Such leaks may be a result of poor construction, faulty design, or faulty building materials.

Regardless of the source of moisture, once water enters a building, mold will be drawn to it -- feeding on ceiling tiles, carpet, insulation, paper backing materials, and drywall. Mold will prefer areas with increased dampness and humidity, such as your basement or bathrooms.

Temperature. Mold grows in temperatures ranging from 60 to 80 degrees Fahrenheit, especially in high-humidity environments. In colder environments below 40 degrees, mold is unable to grow; however, different types of mold have varying degrees of resistance to temperature changes.

Food Source. Mold can consume most organic matter, going beyond just bread, meat, and cheese. Indeed, mold can even eat into fabrics, wood, wallpapers, earth, and greenery. Even a clean home will inevitably contain a food source for mold, which is why proper airflow is important to reduce the chances of mold growth.

Harmful Effects of Mold

Mold can cause a wide range of health effects on people and pets. Mold creates allergens which then create allergic reactions. Allergic reactions to mold are common and result in symptoms resembling hay-fever, such as sneezing, runny nose, and watery eyes.

Mold may also cause sinus infections, respiratory problems, and asthma attacks. Inhalation of these irritants affects your immune system, weakening your body and making it harder to fight mold-related illnesses.

If You Suspect a Mold Problem

Small amounts of mold can be cleaned up with bleach. However, if you suspect any type of mold problem, you should consider enlisting the help of professionals

If you have been affected by mold, you should consider consulting a toxic mold attorney who can advise you regarding your rights and remedies.

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