Natural ventilation, dampness and mouldiness in dwellings in the Waterloo housing development (Durban Metropolitan Area) : a case study of indoor air quality.

Abstract

Dampness can cause the development of moulds in buildings and pose a threat to the quality of the building structure, indoor air quality and health of the occupants. An emerging source of housing related problems are the building materials commonly used in housing construction, which can influence respiratory health. There is concern regarding the quality of the housing stock in the Durban Metropolitan area with regard to dampness and its the potential impact on the health of occupants. To elucidate this issue, a study was conducted to assess natural ventilation, dampness and mouldiness in dwellings of the Waterloo Housing development (Durban Metropolitan Area), between February 2001 and December 2003. A total of 491 randomly selected homes were visually inspected and residents were surveyed by means of a structured questionnaire. Three hundred and eighteen (318) air and surface mould samples were collected in duplicate, totalling 636 samples and analysed in the laboratory. Building characteristics and physical conditions were recorded and noted. Temperature and relative humidity readings were also taken during the survey. After the analysis of the 491 questionnaires, physical conditions of the dwellings were found to be poor and of concern. With the number (1178) and size of habitable rooms in the dwellings; the occupancy of 2414 people with an average of 2.05 persons per room, indicated overcrowding and congestion. About 51% (n=249) of the dwellings surveyed were found to be experiencing dampness (>3m2) and 47% (n=230) had visible surface moulds, primarily on the walls (at least an average of 1m2) . Predominant airborne fungal organism identified included; Aspergillus (23%-indoors, 26outdoors), Cladosporium (47%- indoors, 51%-outdoors), Penicillum (27%-indoors, 26%-outdoors) spp. Natural ventilation was also inadequate in 261 (53%) dwellings, which did not have airbricks. This inadequacy significantly promotes the occurrence of dampness and surface moulds (p < 0.05). With poor ventilation, dampness and mould growth in the dwellings, there was a high number of cases with upper respiratory tract health complaints; like Cough - 25% (n=122), Sinuses - 25% (n=121), flu symptoms 23% (n=llO) lower respiratory infections such as asthma - 27% (n=130), and chest infections - 23% (n=113). Asthma, wheeze, runny nose and allergy to dust were statistically associated with dampness (p < 0.05), mouldiness (p < 0.03) and lack of ventilation (p < 0.01). Buildings separate their occupants from hostile external environments and create a better internal environment for them, therefore dwellings must be constructed in a manner that promotes the health and well being of the occupants. In terms of guiding regulations, there were several omissions and non-compliance with existing local building bye-laws in the construction of houses, leading to adverse implications. Improved workmanship, appropriate material selection and compliance with the relevant guidelines during planning and construction inter alia, are recommended when addressing housing issues, thereby promoting the interest, health and well-being of the users.