Influence of everyday activities and presence of people in common indoor environments on exposure to airborne fungi

In the indoor environment, occupants are exposed to airborne fungi which may cause adverse health effects. The aim of this study has been to collect and provide an overview of the available knowledge on exposure to fungi in connection with everyday domestic activities to be able to advice sensitized people and to facilitate better measurement of exposure levels. The everyday activities include e.g. bed making, walking, vacuuming, and occupancy. Pre-activity exposure levels to airborne fungi ranged between 10 to 1700 cfu/m³. In response to activity, exposure to fungi ranged from 15 to ≥31,000 cfu/m³. The levels of fungal exposure seem to decrease to background levels within app. 30–90 minutes after ceasing an activity. Activities in general cause an increase in exposure levels to fungi, and should be accounted for when correlating exposure levels with health effects. Activities with marked increases in exposure levels were bringing firewood into the house, removing mouldy bread and bed making. Dominant fungal genera found before an activity were often also dominant during an activity, but during an activity other genera were sometimes also found. In most studies fungal species were not identified. The resuspension of fungal spores from floor surfaces as a result of walking depends on the spore load on the floor. The activity induced exposure level is affected by the general exposure in a room, and factors reducing the general exposure may also reduce the activity induced exposure level. Only few studies have investigated the influence of everyday activities on fungal exposure in the home, and, additional research is required to enhance the results of activities already investigated and to describe other everyday and seasonal-related activities in homes.