Written by Hannah Crooks, Biochemist

Dampness and mould in homes are more than an aesthetic problem — they are a public-health concern. A large review by the World Health Organization found that people who live in damp or mouldy housing have markedly higher risks of respiratory symptoms and asthma. World Health Organization

How mould affects health…

Moulds are fungi that produce spores, allergens and irritant compounds. When these become airborne, they can be inhaled or contact the skin and eyes, producing a range of effects from mild irritation to serious lung disease. The U.S. Centres for Disease Control notes that exposure may cause nasal and throat irritation, coughing, wheeze, eye irritation and skin rashes; people with allergies or asthma often have stronger reactions. CDC

Common and well-documented health outcomes

• Upper respiratory symptoms — sneezing, nasal congestion, sore throat and chronic cough are frequently reported in damp dwellings. NCBI
  
• Wheeze and asthma exacerbation — mould exposure is associated with increased wheeze and more frequent or severe asthma attacks in people who already have asthma. The WHO review reported substantially increased risks of respiratory symptoms and asthma in occupants of damp/mouldy buildings. World Health Organization
  
• New-onset asthma — evidence supports that living in damp or mouldy housing can contribute to the development of asthma in susceptible individuals. NCBI
  
• Allergic rhinitis and eczema — moulds can act as allergens; they are linked to hay fever–type symptoms and worsening of eczema. CDC
  
• Hypersensitivity pneumonitis (extrinsic allergic alveolitis) — repeated inhalation of fungal antigens in damp buildings can trigger this immune-mediated inflammatory lung disease in some people. NCBI
  
• Infections in vulnerable people — in particular, immunocompromised people and those with chronic lung disease can develop fungal lung infections (for example, forms of aspergillosis). nhs.uk
  

Who is at greater risk?…

Children, older adults, people with asthma, other chronic lung diseases, allergies, or weakened immune systems are more likely to experience harm from damp and mould. Public health investigations and reviews emphasise that long-term exposure can be particularly damaging to children’s respiratory health. CDC

Severity and real-world consequences…

While many exposures cause reversible irritation, long or intense exposure can lead to persistent disease and, in rare but tragic cases, severe outcomes. National investigations and policy reviews (particularly in the UK) have highlighted deaths and serious illness linked to chronic, unremediated mould in housing. GOV.UK

What the science recommends…

Public-health guidance stresses prevention and swift remediation: control moisture sources (fix leaks, improve ventilation), remove mould safely, and reduce occupant exposure during cleanup. These practical steps reduce airborne spores and the health burden associated with damp housing which leads to mouldy environments. US EPA

References

WHO — Guidelines for indoor air quality: dampness and mould. World Health Organization
CDC — Mold: health effects & facts. CDC
EPA — Mold and health / mold prevention guidance. US EPA
Institute of Medicine / NCBI — Damp Indoor Spaces and Health (review/report). NCBI
UK Government — Understanding and addressing the health risks of damp and mould in the home. GOV.UK
NHS — Aspergillosis and mould-related risks (patient guidance). nhs.uk