Inhibitory effect of mould growth on formaldehyde emissions from medium-density fibreboards: Evidence from field observations in three experimental houses

The occurrence of mould and effect of formaldehyde emission on indoor air pollution has been widely reported. However, the potential effect of mould on formaldehyde emissions from building materials has been rarely examined. In this study, the formaldehyde emission from medium-density fibreboards was monitored in three full-scale unoccupied experimental houses for 24 months. Moulds were infested in two out of the three houses. Different indoor formaldehyde concentrations were observed accordingly. Three different stages of variation in concentrations were observed among the houses. In the first stage, when there was no mould growth in any of the houses, indoor formaldehyde concentrations varied in the same way. In the second stage, a large amount of mould was infested in one of the houses, and its formaldehyde concentration was reduced substantially and exhibited a trend opposite to those of the other two houses. In the third stage, 5% of the medium-density fibreboards were covered with mould in another house, and the difference in formaldehyde concentration compared to that in the house without mould growth was increased after that. The different indoor formaldehyde concentrations due to the presence of mould in these houses indicated the inhibitory effect of mould growth on formaldehyde emissions.