A total of 630 randomly selected dwellings were surveyed for visible signs of moisture damage by civil engineers, and questionnaire responses were collected from the occupants (a total of 1,017 adults) to analyse the association between moisture damage and occupant health. A three-level grading system was developed, which took into account the number of damage sites in buildings and estimated the severity of the damage. In the present study, this grading system was tested as an improved model of moisture damage-related exposure in comparison to a conventional two-category system: based on independent, technical criteria it also allowed dose-response to be estimated. The questionnaire probed 28 individual health symptoms, based on earlier reported associations with building moisture and mould-related exposure. Criteria in evaluating the goodness of the selected exposure model were (1) dose-responsiveness and (2) higher risk compared to a two-level classification. Dose-responsiveness was observed with the three-level classification in 7, higher risk in 10, and both criteria in 5 out of 28 health symptoms. Two-level classification had higher risk in 4 health symptoms. Dose-dependent risk increases for respiratory infections and lower respiratory symptoms, and recurrent irritative and skin symptoms were observed with the three-level classification using symptom score variables. Although the results did not unambiguously support the three-level model, they underline the importance of developing more accurate exposure models in assessing the severity of moisture damage.

This study was conducted in a school center that had been the focus of intense public concern over 2 years because of suspected mold and health problems. Because several attempts to find solutions to the problem within the community were not satisfactory, outside specialists were needed for support in solving the problem. The study group consisted of experts in civil engineering, indoor mycology, and epidemiology. The studies were conducted in close cooperation with the city administration. Structures at risk were opened, moisture and temperature were measured, and the causes of damage were analyzed. Microbial samples were taken from the air, surfaces, and materials. Health questionnaires were sent to the schoolchildren and personnel. Information on the measurements and their results was released regularly to school employees, students and their parents, and to the media. Repairs were designed on the basis of this information. Moisture damage was caused mainly by difficult moisture conditions at the building site, poor ventilation, and water leaks. Fungal genera (concentrations <200 colony-forming units (cfu)/m3, <3000 cfu/cm2) typical to buildings with mold problems (e.g., Aspergillus versicolor, Eurotium) were collected from the indoor air and surfaces of the school buildings. Where moisture-prone structures were identified and visible signs of damage or elevated moisture content were recorded, the numbers of microbes also were high; thus microbial results from material samples supported the conclusions made in the structural studies. Several irritative and recurrent symptoms were common among the upper secondary and high school students. The prevalence of asthma was high (13%) among the upper secondary school students. During the last 4 years, the incidence of asthma was 3-fold that of the previous 4-year period.

This study was motivated by a need to establish criteria for evaluating observations of moisture damage with respect to exposure and adverse health effects. The database used included information on moisture damage from 164 dwellings and questionnaire data collected from the occupants. Moisture damage observations were classified according to eleven variables characterising damage by, for example, size, duration and type of damaged material. Five health symptom scores were devised based on the questionnaire data. Visible mould associated with respiratory infections, irritative and skin symptoms. Damage <1 m² in size was associated with general and skin symptoms, and >4 m² in size associated with respiratory infections and skin symptoms. Damage of <3 years duration was associated with respiratory infections and damage that had existed for 3–10 years was associated with general, irritative and skin symptoms. Symptom scores were associated more frequently with damage to organic rather than inorganic materials. Criteria used to evaluate the association between the classification of moisture damage and symptom scores were excess risk compared to a two-category classification, dose responsiveness, and biological plausibility of the findings. Despite the complexity of interpretation, the results show that more accurate models of moisture damage with respect to exposure and adverse health effects can be established.

A grading system was developed to rate the moisture damage profile of dwellings and to study the relationship between moisture-induced indoor air problems and occupant health. A total of 630 randomly selected houses and apartments, built between 1950 and 1989, were visually inspected. Moisture observations were standardized into three damage levels. Thus, a system to classify the homes into three grades was devised. The two grades of homes associated with the highest levels of damage were graded as index homes.Overall, 51% of the sample had some kind of moisture fault in them and one in every three homes (33%) was classified as an index home. The mean number of damage incidents in the index dwellings varied from 1.4 to 2.6. The mean number of damage incidents in the reference homes was 0.28. Prevalence of index dwellings was significantly higher (p < 0.01) in houses (38%) than in apartments (26%). There was no major difference in the prevalence of index buildings in houses built in any particular decade (30-35%). Moisture was observed in 28% of bathrooms, in 10% of kitchens, and in 17% of other spaces. Indoor relative humidity (RH) levels were low in most homes. IMPLICATIONSThe grading system developed in this study provides a method of analyzing moisture findings and their intensity in dwellings. This knowledge is needed both for understanding the profile of existing moisture damage, particularly in cold climates, and for assessing how different levels of moisture damage relate to mold exposure and on occupant health. Therefore, the grading system may be useful both in assessing the condition of a building as a surrogate of exposure in epidemiologic studies, and as a decision-making instrument in assessing need for repair.

This study was motivated by a need to establish criteria for evaluating observations of moisture damage with respect to exposure and adverse health effects. The database used included information on moisture damage from 164 dwellings and questionnaire data collected from the occupants. Moisture damage observations were classified according to eleven variables characterising damage by, for example, size, duration and type of damaged material. Five health symptom scores were devised based on the questionnaire data. Visible mould associated with respiratory infections, irritative and skin symptoms. Damage <1 m 2 in size was associated with general and skin symptoms, and >4 m2 in size associated with respiratory infections and skin symptoms. Damage of <3 years duration was associated with respiratory infections and damage that had existed for 3-10 years was associated with general, irritative and skin symptoms. Symptom scores were associated more frequently with damage to organic rather than inorganic materials. Criteria used to evaluate the association between the classification of moisture damage and symptom scores were excess risk compared to a two-category classification, dose responsiveness, and biological plausibility of the findings. Despite the complexity of interpretation, the results show that more accurate models of moisture damage with respect to exposure and adverse health effects can be established.