Mould exposure can cause wheezing, breathing problems and irritated eyes, nose and skin, even in people without mould allergies. People with asthma or allergies can be more sensitive to its effects.

Fresh attention has followed biohacker Bryan Johnson showing himself in a full hazmat suit after mould was found in his home gym. His video has highlighted a health issue linked to damp indoor environments.

The US Centers for Disease Control and Prevention (CDC) says damp or mouldy environments may cause a stuffy nose, sore throat, coughing, wheezing, burning eyes and skin irritation. Some people have no symptoms, while severe reactions can occur in others.

What Black Mould Does to the Body

Black mould is a fungus that may look dark green or black. The term commonly refers to Stachybotrys chartarum, which can grow on cellulose-containing materials such as paper, wood products and drywall.

Mould releases spores into the air and can also produce microbial volatile organic compounds, or mVOCs. People with mould allergies can react to the spores, while mVOCs may also irritate people without allergies.

Common symptoms include sneezing, coughing, nasal congestion and eye irritation. Exposure can also worsen asthma, causing wheezing, shortness of breath, coughing and chest tightness.

For people allergic to mould, symptoms can develop immediately after exposure. People without allergies may have no symptoms, although exposure can still cause irritation.

People with asthma or chronic obstructive pulmonary disease may be more vulnerable to irritation. Those with weakened immune systems face a separate risk because mould exposure can cause fungal infections.

Black mould rarely causes serious illness or death, according to Cleveland Clinic. There is also no evidence that it causes memory loss, nosebleeds, body aches or mood disorders.

That distinction matters because the term 'black mould' can sound more alarming than the evidence supports. Health concerns are not limited to one colour or species, as damp conditions can allow different moulds to grow indoors and affect susceptible people.

A review of peer-reviewed studies and meta-analyses published up to late 2009 found consistent associations between indoor dampness or mould and asthma, wheeze, cough, respiratory infections, bronchitis, allergic rhinitis, eczema and upper respiratory symptoms.

The review found these associations in both allergic and non-allergic people. It also found strong evidence that dampness or mould can worsen asthma in children, while evidence for specific measured microbial agents in dust was more limited.

Read more

Preventing Mould Exposure

Mould grows where moisture is present. Indoor humidity should be kept between 30% and 50%, while leaks should be fixed promptly to reduce conditions that allow mould to grow.

Exhaust fans can help control moisture, while wet areas should be dried quickly. Other measures include using a HEPA filter and sealing off an affected room when dealing with mould.

Trying to remove mould yourself can spread spores through the air. Professional mould removal may be needed when an affected area requires specialist treatment.

People should also consider the source of the moisture rather than treating visible mould. Fixing leaks, drying wet materials and improving ventilation can help address the conditions that allow mould to persist indoors.

A healthcare provider or allergist can diagnose a mould allergy. Tests may include a skin-prick test, while treatment can include nasal irrigation, antihistamines, nasal corticosteroids, decongestants, montelukast or asthma inhalers.

Reducing exposure is central to managing mould-related symptoms. The World Health Organization says preventing or minimising persistent dampness and microbial growth is the most important way to avoid adverse health effects.

The evidence does not mean every mould exposure causes illness. However, damp indoor environments are linked with respiratory symptoms, allergies and asthma, making moisture control an important way to reduce exposure.

Frequently Asked Questions

  • What are common symptoms of mould exposure?
    Common symptoms include sneezing, coughing, nasal congestion, and eye irritation. Mould exposure can also worsen asthma symptoms.
  • How can mould exposure be prevented?
    Prevent mould exposure by controlling indoor humidity, fixing leaks, using exhaust fans, and drying wet areas quickly.
  • Who is more vulnerable to mould exposure?
    People with asthma, allergies, chronic obstructive pulmonary disease, or weakened immune systems are more vulnerable to mould exposure.
  • What should you do if you find mould in your home?
    If you find mould in your home, consider contacting professionals for removal and take steps to control moisture and prevent further growth.
Read more