Mold Frequently Asked Questions

Molds are microscopic fungi that can grow both indoors and outdoors. They are an integral part of our natural environment and play an important role in the ecosystem. Molds are decomposers. They do the job of breaking down dead organisms and recycling their nutrients. While we require molds in our environment, their growth inside buildings is a matter of concern as they have the potential to cause health problems.

The exact number of species of fungi that exists has not been established. However, there is a general consensus among experts that thousands of fungi species exist. In the United States alone, there are about one thousand mold species.

Molds grow from tiny particles called mold spores, which are practically ubiquitous. Mold spores float around in the atmosphere everywhere, outside and inside our homes. Mold spores can grow into mold anywhere where the environment is favorable for their growth. Besides oxygen, molds require the following three things to grow:

• Favorable temperature – Most molds grow well in the same temperature range humans prefer. A few mold species can grow in temperatures as low as 39°F (4°C). However, most mold species do not grow at temperatures below 40°F (4.4°C) or in excess of 100°F (37.8°C). When the temperature is unfavorable, mold spores become dormant. They become active and grow into molds when the temperature becomes favorable. It is only at extreme temperatures that mold spores die.
• Moisture – Mold requires considerable moisture to grow. The moisture requirement is different for different species. Most mold species require water vapor content equivalent to a relative humidity of 70% or more. Humans require less moisture than molds, and so among all the factors that molds need for growth, this is the one we can control most easily.
• Food – Molds can feed on almost any substance that is organic (carbon atoms). Molds can grow on most common home materials such as paper, wood, organic fibers, and carpets. As almost all home materials have the capacity for providing molds the nutrients they require for growing, removing 'mold food' from your home environment completely is virtually impossible.

Molds enter a building in form of mold spores, which enter your house through the air. When the spores get the right environment, they grow into molds. Inside a building, molds are usually found in areas where moisture content is high.

• Alternaria
• Penicillin
• Aspergillus
• Cladosporium

Indoors molds usually grow in: drapes, carpets, leather, upholstery, wood products, clothing, ductwork, ceiling tiles, paper, books, cardboard, rags, household dust, and wallpaper.

When all the four elements that molds require for growing are present in the environment, molds can germinate within 48 hours. Mold spores can take 1 to 12 days to spread to other areas beyond their initial growth area.

Mold spores are present in the air. When an area where mold concentration is high is disturbed, the levels of mold spores in the surrounding air rise exponentially. In addition, you can be exposed to molds when you touch moldy items or when you eat food on which molds are present.

Some people are more susceptible to the effects of molds than others. People who are more susceptible to health problems caused by molds have a lower tolerance to them. However, most of us are likely to experience at least some symptoms of mold exposure if we are continuously exposed to high or severely high levels of mold.

People who are more likely to become ill after being exposed to small or moderate levels of mold include:

• Individuals who have asthma or other respiratory problems or those who are genetically predisposed to these conditions
• Individuals who have allergies or have a genetic predisposition to allergies
• Individuals with a weak immune system (such as HIV patients or individuals undergoing chemotherapy)
• Elderly people
• Infants and young children
• Pregnant women

No, only a few molds can cause health problems in healthy humans. However, people with a history of allergic reactions or with a compromised immune system may be susceptible to all types of mold.

The common symptoms of mold exposure are:

• Sinus and nasal congestion
• Difficulty breathing and/or wheezing
• Eye irritation (such as red, watery, or itchy eyes)
• Throat irritation
• Cough
• Headache
• Skin irritation
• Tiredness
• Headache
• Nausea

Outdoor molds are most likely to be found in damp, shady areas or areas where organic matter, such as leaves, is decomposing. You can limit your exposure to outdoor molds by avoiding such places. You can prevent molds from growing inside your home by ensuring the humidity level of the air inside is less than 70% and by ensuring proper air filtration inside the house.

If mold is present in certain areas of your house, chances are there is some water problem in those areas. To get rid of indoor molds, clean up the areas they are growing and undertake any necessary plumbing work. You can remove molds from hard surfaces, such as sheet metals, using commercial home cleaners.

The use of bleach for removing molds from hard surfaces is not recommended for several reasons, including health risks and its inability to completely eliminate allergic reactions as dead molds can still trigger reactions. Commercial home cleaning solutions are safer and more effective. If using bleach, ensure proper safety measures are followed.

The following steps help you prevent mold growth inside your house:

• Ensure no water leakage. Fix any leaks immediately.
• Ensure proper air circulation. Use fans in areas without windows.
• Maintain a gap between furniture and walls.
• Install exhaust fans in kitchens, laundry rooms, and bathrooms.
• Avoid spilling liquids on carpets, bedding, and clothing. Clean and dry wet materials promptly.

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You can read our helpful guide here.