Carpet serves as an important reservoir for dust exposure because it acts as both a source and a sink in the indoor environment. Carpets can also retain moisture and potentially support fungal growth. This is especially important for the roughly 8% of the US population that are affected by asthma, in addition to people affected by other respiratory disorders.
We need to understand what factors are the most important determinants that contribute to microbial growth in carpet. We recently published a new study that measures how microbial growth is related to that relative humidity (RH) in the air (50, 85, 90, 95, and 100% RH), carpet fiber material type (nylon, olefin, and wool), and dust loading (no dust, autoclaved dust, and regular dust). We used quantitative polymerase chain reaction (qPCR) to determine total fungal quantity and scanning electron microscopy (SEM) to visualize fungal structures as they grow in these different conditions.
Our findings indicate that moisture is the most important factor under most circumstances that contributes to fungal growth in carpet dust. The dust loading is the next most important factor, and finally carpet fiber type also had an important but smaller effect.
Check out the cool pictures in the open-access article, entitled “Morphology and quantification of fungal growth in residential dust and carpets.” It can be found in the journal Building & Environment at this link: https://doi.org/10.1016/j.buildenv.2020.106774
Graduate Fellow, The Ohio State University