No abstract

The release and transport of fungal spores from water-damaged building materials is a key factor for understanding the exposure to particles of fungal origin as a possible cause of adverse health effects associated to growth of fungi indoors. In this study, the release of spores from nine species of typical indoor fungi has been measured under controlled conditions. The fungi were cultivated for a period of 4-6 weeks on sterilized wet wallpapered gypsum boards at a relative humidity (RH) of approximately 97%. A specially designed small chamber (P-FLEC) was placed on the gypsum board. The release of fungal spores was induced by well-defined jets of air impacting from rotating nozzles. The spores and other particles released from the surface were transported by the air flowing from the chamber through a top outlet to a particle counter and sizer. For two of the fungi (Penicillium chrysogenum and Trichoderma harzianum), the number of spores produced on the gypsum board and subsequently released was quantified. Also the relationship between air velocities from 0.3 to 3 m/s over the surface and spore release has been measured. The method was found to give very reproducible results for each fungal isolate, whereas the spore release is very different for different fungi under identical conditions. Also, the relationship between air velocity and spore release depends on the fungus. For some fungi a significant number of particles smaller than the spore size were released. The method applied in the study may also be useful for field studies and for generation of spores for exposure studies.

The relevance of particle mass, surface area or number concentration as risk indicators for health effects in non-industrial buildings has been assessed by a European interdisciplinary group of researchers (called EUROPART) by reviewing papers identified in Medline, Toxline, and OSH. Studies dealing with dermal effects or cancer or specifically addressing environmental tobacco smoke, house dust-mite, cockroach or animal allergens, microorganisms and pesticides were excluded. A total of 70 papers were reviewed, and eight were identified for the final review: Five experimental studies involving mainly healthy subjects, two cross-sectional office studies and one longitudinal study among elderly on cardiovascular effects. From most studies, no definite conclusions could be drawn. Overall, the group concluded that there is inadequate scientific evidence that airborne, indoor particulate mass or number concentrations can be used as generally applicable risk indicators of health effects in non-industrial buildings and consequently that there is inadequate scientific evidence for establishing limit values or guidelines for particulate mass or number concentrations.

No abstract

Insufficient cleaning may be a cause of the Sick Building Syndrome. Various improvements in cleaning methods have been tested in order to clarify whether they reduced the concentration of airborne dust, and the concentration of dust on surfaces, or whether the concentration of different microbiological components in the dust was reduced. The interventions were performed in an administration building, a school and a kindergarten. Dust measurements were performed on one day every week for a period of 28 weeks, using different interventions. The airborne dust concentration was measured by sampling on filters during the day. The concentration of surface dust was measured by the BM‐Dustdetector foil sampling method. Dust samples were collected from the floors, after which analyses for different microbiological components were performed. Sampling from surfaces and the floor were performed prior to cleaning in order to ascertain the levels to which the room occupants had been exposed. One of the findings was a reduction in the dust concentration on the so‐called easily accessible surfaces. Correlations between surface dust and airborne dust were also found. Furthermore, correlations between the measurements and other factors, such as activity during the day, and the climate, were obtained. Important findings of the study were the observations made on the relations between cleaning and dust in the indoor environment and the measuring methods applied.