The objective of this study was to establish a national relative moldiness index for homes in the United States.
As part of the Housing and Urban Development's American Healthy Homes Survey, dust samples were collected by vacuuming 2 m2 in the bedrooms plus 2 m2 in the living rooms from a nationally representative 1096 homes in the United States using the Mitest sampler. Five milligrams of sieved (300 μm pore, nylon mesh) dust was analyzed by mold-specific quantitative polymerase chain reaction for the 36 indicator species in 1096 samples.
On the basis of this standardized national sampling and analysis, an “Environmental Relative Moldiness Index” was created with values ranging from about −10 to 20 or above (lowest to highest).
The Environmental Relative Moldiness Index scale may be useful for home mold-burden estimates in epidemiological studies.