Science Inventory

Comparison of ERMI results for dust collected from homes by an electrostatic cloth and by the standard vacuum method

Citation:

Vesper, S., L. Wymer, D. Cox, G. Dewalt, E. Pinzer, W. Friedman, AND P. Ashley. Comparison of ERMI results for dust collected from homes by an electrostatic cloth and by the standard vacuum method. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE. Taylor & Francis, Inc., Philadelphia, PA, 18(9):423-429, (2021). https://doi.org/10.1080/15459624.2021.1946254

Impact/Purpose:

Asthma is the most common chronic disease of children in the US, afflicting nearly 10%. Mold exposures have been associated with asthma development and exacerbation. Therefore, it is important to have accurate measures of mold exposures. The Environmental Relative Moldiness Index (ERMI) was created, in conjunction with HUD, to do that To collect dust for mold analyses, HUD developed a standard vacuum sample method. However, this method of collection is not always practical. This study compared the use of an electrostatic cloth to the standard vacuum method for dust collection. We found that an EC cloth sample is effective in identifying very high mold levels 96% of the time.

Description:

The Environmental Relative Moldiness Index (ERMI) is a scale used to compare mold contamination levels in United States (US) homes. To create the ERMI scale, a nationally representative set of U.S. homes was selected (n = 1096). From each of these homes, a standard vacuum-dust sample was collected and then 36 common molds, the 26 Group 1 and 10 Group 2 molds, as grouped for forming the ERMI metric, were quantified using quantitative PCR assays. However, in investigations of mold in homes, it is not always practical or even possible to collect dust using the standard vacuum method. Therefore, we performed a comparative study of dust samples collected in the same homes (n = 151) by the standard vacuum method and by an electrostatic cloth (EC) method. First, floor dust was collected by vacuuming a 2 m2 area in the living room and a 2 m2 area in a bedroom, directly adjacent to the sofa or bed, for 5 min each with a Mitest™ sampler-fitted vacuum. Second, immediately after the collection of the vacuum dust sample, an EC dust sample was collected by wiping above-floor horizontal surfaces in the living room and bedroom. Then, the ERMI analysis of each sample was performed by a commercial laboratory. The results showed the average concentrations of 33 of the 36 ERMI molds were not significantly different in the vacuum and EC samples. Also, the average summed logs of the Group 1 molds, Group 2 or ERMI values were significantly (p < 0.001) correlated between the vacuum and EC samples. Logistic regression indicated that an EC sample could identify homes in the highest ERMI quartile 96% of the time by using the same ERMI value cutoff as vacuum sample ERMI value cutoff and 35% of samples proved to be false positives. When it is not practical to obtain the standard vacuum-dust sample, an EC sample can provide a useful practical alternative for ERMI analyses.