Mold spores are everywhere — inside and outside at all temperatures, on our fruits and bread, and in our homes, schools, and workplaces. Some molds are important to food production and medicines, but others can cause allergies. While there is no way to completely remove mold, we can reduce the amount in our environment.
Mold is produced by fungi as part of the decay process for organic matter.
Fungi spread in the environment by releasing mold spores.
Exposure to mold spores can cause allergy symptoms.
People with a chronic lung condition or immune compromise can have more severe symptoms.
Managing mold is possible by reducing humidity and cleaning up mold growth.
What is mold?
You might recognize mold as the white or green powdery substance growing on clementines, bread, strawberries, or blueberries. These are mold colonies, and as part of the natural environment outside they are vital to breaking down dead organic material into useful nutrients for plants.
Mold is everywhere. There are some factors that can add to its growth and some which inhibit it.
- Fruit. Mold spores can land on the clementines sitting on your counter and will start reproducing when the environmental conditions are right.
- Temperature. Molds grow best in warmer temperatures and at a higher humidity (over 50%), which is why we store food in a refrigerator.
- Unavoidable. We cannot avoid mold exposures, even in a surgical operating room.
The mold spores are produced by fungi, allowing it to disperse in the environment. They are everywhere, including in our homes, schools and office buildings.
Can mold cause an allergy?
Yes, mold can cause an allergy. The symptoms can include:
- Stuffy nose
- Sore throat
- Shortness of breath
- Burning eyes
- Skin rash
For those who already have asthma, the symptoms can be more serious. People who have a chronic lung condition or who are immune compromised can develop a lung infection.
Being exposed to a damp building with mold can make asthma worse and may also cause asthma to develop. The National Institute for Occupational Safety and Health (NIOSH) has conducted research on damp buildings as a risk factor for developing asthma.
What is hypersensitivity pneumonitis?
People who are exposed over a long period of time to mold in their environment, such as at work or home, can develop hypersensitivity pneumonitis (HP). This condition is not contagious, but is caused by the person’s immune system responding to the mold spores.
A hypersensitivity reaction causes lung inflammation which can look similar to pneumonia. Symptoms of HP include:
- Profound fatigue
- Night sweats
- Fever and chills
- Muscle aches
- Shortness of breath
Symptoms usually begin within 2 to 9 hours after being exposed and may last for 1 to 3 days. A more subtle and progressive onset is also possible where symptoms worsen over time. This can make it very challenging to diagnose the source of the problem if symptoms continue even when away from the mold source.
What about toxic or black mold?
Molds can release harmful toxins. One example is a greenish-black mold called Stachybotrys chartarum which likes to grow on materials that are high in cellulose (plant material). Examples include fiberboard, gypsum board, and paper.
This mold is what causes the so-called sick building syndrome and may also cause infants to have bleeding in the airways unexplained by other causes.
According to the Centers for Disease Control and Prevention (CDC), there is no definitive association between Stachybotrys chartarum and infants with acute idiopathic pulmonary hemorrhage.
As with any other mold, water exposure increases the likelihood of mold and steps can be taken to reduce mold growth.
Should I get my home tested for mold?
No, if mold is visible then sampling is not necessary. In addition, there is no federal standard for mold or mold spores. Therefore, there is no way to establish compliance because there are no guidelines.
Is it possible to remove mold?
Yes, and it is important to reduce the opportunities for mold to grow in your home if family members have asthma or have an immune-compromised condition.
Simple steps to remove mold in your home or workplace include:
- Notice. If you smell mustiness – you don’t need to see the mold, you can smell it.
- Identify. Mold looks like spots but can be different colors.
- Remove. Mold from hard surfaces using bleach (1 cup bleach added to 1 gallon of water).
- Use specific chemicals. Other biocides are available in spray containers specifically labeled for the removal of mold.
- Avoid mixing chemicals. Never mix bleach with ammonia or anything else but water – it can create a toxic gas.
- Circulate the air. Open windows to provide fresh air while cleaning and wear goggles, gloves and boots.
- Fix and replace. Moldy ceiling tiles and other absorbent building materials.
If the home or workplace still smells moldy but you cannot see any evidence of mold, it may be hidden behind wallpaper or paneling, above ceiling tiles, behind furniture, or under carpeting or pads.
If you suspect hidden mold may be a problem, expert guidance is necessary to avoid making the problem worse. For example, if mold is growing behind wallpaper, peeling it back may cause a massive spore release.
How do I keep mold from growing?
Mold is ubiquitous, but certain areas tend to be more humid than others and thus more prone to mold growth. If you live in a basement apartment or sleep in a basement bedroom, you may be in a more damp environment. One sign of excess humidity is condensation on the inside of your windows.
Remember that mold likes humidity, so keeping your home under 50% humidity can help. Humidity levels can be checked with a humidity meter (or “hygrometer”) for less than $50. Use a dehumidifier if you live in a very humid environment.
Other tips to reduce humidity include the following:
- Make sure your laundry exhausts to the outside and that air flows freely in your home.
- Clean your air conditioning filters every 90 days, or when the season changes.
- Use exhaust fans when cooking.
- Avoid installing carpeting in areas which frequently get wet, such as by a drinking fountain or sink.
Be aware that not all molds are bad
Penicillin is a powerful antibiotic that changed the course of medical history. Scottish physician Alexander Fleming discovered penicillin by accident in 1928 when he left a petri dish sitting next to an open window.
Fleming had served in the Army Medical Corps during World War I and noticed the soldiers were dying of infections, not just wounds. This observation prompted him to investigate ways to combat infection.
While working on a way to fight a common staphylococcal bacteria, Fleming put the bacteria on a petri dish and placed it by the window where it became contaminated by mold spores. He soon found that the bacteria near the mold spores were dying. Fleming deduced that the mold produced a substance that killed the bacteria. This substance was later named penicillin after the genus of the mold which produced it — Penicillium.
By 1945, Fleming and two other scientists had discovered a way to produce penicillin in large quantities. The antibiotic won the Nobel Prize in Physiology/Medicine that year and continues to be used today.
Tips to remember when managing mold
As with other allergies, like pollen, it is difficult to identify which specific allergen your body might be reacting to. Try taking steps to reduce the likelihood of mold growing in the first place. Check the humidity in your home and office and take steps to reduce the humidity by increasing ventilation and using air conditioning or a dehumidifier.
Next, clean up mold already established in your home. If the area is small (less than 10 square feet) attack the mold as described above and keep it clean. Bathrooms are particularly challenging because of the high humidity. Try leaving fans on and cleaning trouble spots regularly.
By reducing the humidity and cleaning up mold in your home, you may notice that symptoms improve. If your symptoms do not improve, the American Academy of Allergy, Asthma, and Immunologists suggests consulting with an allergist about narrowing down which trigger is causing your discomfort.
- Centers for Disease Control and Prevention. What is mold?
- Centers for Disease Control and Prevention. Facts about stachybotrys chartarum.
- Centers for Disease Control and Prevention. You can control mold.
- US Environmental Protection Agency. Mold testing or Sampling.
- Singapore Medical Journal. Alexander Fleming (1881–1955): Discoverer of penicillin.
- American Academy of Allergy, Asthma and Immunology. Mold allergies.