Exposure Assessment in Moisture-Damaged Buildings

Essentials

• Symptoms related to indoor air are relatively common and their aetiology is usually something else than moisture-damage.
• When discussing mould in moisture-damaged structures and materials, the word mould covers moulds, yeasts and bacteria (e.g. Actinomycetes).
• It is not definitely known which factors in these buildings cause the symptoms and illnesses in the users of the buildings. Therefore, the investigation of symptoms and diseases related to moisture and mould damages is difficult.
• Before associating the patient's symptoms or illness with moisture damage the physician must have a statement from a building technology expert that confirms a considerable moisture and mould damage in the inspected building.
• The most important task in all cases where adverse health effects related to moisture and mould damages are suspected is to repair the identified damage as soon as possible to stop exposure.
• It is important to investigate the damaged building and the symptomatic individuals at the same time when suspecting symptoms or diseases to be related to a moisture- and mould-damaged building.
• Diagnosis of diseases that are manifested in moisture-damaged buildings is based on the confirmation of exposure, clinical findings and exclusion of other aetiological factors.
• Adverse health effects associated with moisture-damaged buildings may present as transient irritation symptoms only or may progress to rhinitis, asthma or even allergic alveolitis. Exposure may also be associated with general symptoms (e.g. headache, fatigue and nausea).
• Investigation and treatment of symptoms and diseases related to moisture-damaged buildings is in most cases the responsibility of primary health care. Patients with a suspicion of asthma or other disease associated with the building should be sent to special clinics.

Epidemiology

• Experiencing symptoms related to indoor air is common. Every fifth person in office work reports weekly irritation of eyes and upper respiratory tract due to indoor air. The symptoms are usually explained by other environmental factors than moisture or mould damage. Dry or stuffy indoor air, dust and odours released from materials may be associated with the symptoms.
• In Finland, research has revealed that in approximately 10% of one-family houses and flats there are significant moisture and mould damages. The same applies to 20-25% of the floor area of schools and social and health care facilities.
• There is evidence on the association between, on the one hand, moisture and mould damage, and, on the other hand, asthma and airway symptoms. There is a temporal association between these, but the cause of symptoms and diseases is not known for sure.
• Flat roof frequently cause problems. Even newer buildings can be damaged because of faulty building techniques or leaking pipes.

Clinical picture

Investigation

Actions

• Potential other factors causing indoor air problems should be investigated and repaired (e.g. ventilation flaws, temperature conditions, emissions from materials, dirt and dust).
• It is most important to quickly repair a significant mold and moisture damage.
• If the number of symptomatic persons is low (one or a few) in a moisture-damaged building and the symptoms are mild irritation symptoms, it may be sufficient that, in addition to the repairing of the damage, symptomatic treatment is provided and the patients are followed-up until the symptoms subside.
• If the number of persons suffering from symptoms is higher or if the symptoms are more severe (asthma, recurring infections), the premises should be technically inspected without delay (by qualified experts on building construction or indoor air quality, municipal health authorities, occupational health services).
• There are no laboratory or other examinations that could be used to connect, with certainty, moisture and mold damage to symptoms or diseases.
• Suspicion of asthma warrants further investigations in a specialist clinic.
• Local regulations regarding occupational diseases should be taken into account.

Indicator microbes in a moisture-damaged building

• Following microbes require plenty of water: Aspergillus fumigatus, Exophiala, Phialophora, Trichoderma, Ulocladium, Stachybotrus, Fusarium, Actinomycetes, yeasts, gram-negative bacteria (e.g. Pseudomonas).
• Microbes requiring moderate or small amounts of water: Aspergillus versicolor, Eurotium, Penicillium (P. chrysogenum, P. auratiogriseum), Wallemia.
• Some microbes can produce mould fungus toxins, e.g. Stachybotrys chartarum (atra), Aspergillus versicolor and Trichoderma viride.
  • The role of microbial toxins in symptoms has not been established. There are no such methods for examining toxins in indoor environment that would allow reliable assessment of potential exposure. The relation between toxins and symptoms has not been shown in studies.
• Finding the aforementioned microbes in a building mainly supports the technical evaluation of the construction, but their role is minor in assessing the health impact.