Public-health bodies including the WHO, US CDC and US EPA link indoor dampness and mold with an increased risk of respiratory symptoms, allergic responses and asthma exacerbation in some people. The strength of any effect depends on the extent of dampness, how long it has been present, and individual sensitivity.
Who tends to be more affected
- People with asthma, allergies or other chronic respiratory conditions
- People who are immune-compromised
- Infants and young children in persistently damp homes
- Older adults, and anyone with an existing lung condition
Common reported symptoms
Nasal congestion, throat irritation, coughing or wheezing, eye irritation, and in sensitised people a worsening of asthma. Symptoms that improve when you leave the property and return at home are worth noting and discussing with a clinician.
This website does not provide medical diagnosis. If you or someone in the home has significant or persistent symptoms, speak with a qualified healthcare professional.
What helps
The health response and the building response are the same: find and correct the moisture, remove or clean affected materials properly, and keep humidity controlled so it does not return.
The kinds of response
“Mold and health” covers several different things, and they matter for different people:
- Irritation. Damp, moldy air can irritate the eyes, nose, throat and airways of anyone if exposure is high enough — this is not an allergy, just a response to the particles and compounds present.
- Allergy. Some people are sensitised to mold and react to much lower levels, with hay-fever-type symptoms or, in people with asthma, a worsening of their asthma.
- Infection. Rare, and essentially limited to people who are significantly immune-compromised. It is not a risk for the general population from ordinary indoor growth.
What raises the risk
The strength of any effect depends on how much dampness there is, how long it has been present, and individual sensitivity. People with asthma, allergies or chronic respiratory conditions, people who are immune-compromised, infants and young children in persistently damp homes, and older adults tend to be more affected. A larger and longer-standing damp problem is more likely to matter than a small recent one.
If someone in the home is affected
Note the pattern — symptoms that improve when the person is away from the property and return at home are worth raising with a doctor, who can assess whether the two are linked. In parallel, treat it as a building problem: find and correct the moisture, remove or properly clean affected materials, and keep humidity controlled so it does not come back. The health response and the building response are the same work. This site does not provide medical diagnosis or advice.