ERMI Data Used as a Predictor of Asthma

by Jill Breysse

Many private firms recommend collecting mold samples to determine whether a home has a mold problem. Yet, federal and state agencies, and many nongovernmental organizations (including NCHH) don’t think it’s necessary. Instead, we support visual assessment over mold sampling when identifying a mold problem and choosing the appropriate remediation. In two recent articles, investigators used the Environmental Relative Moldiness Index (ERMI) to analyze settled dust samples and found a link between mold and asthma development by age seven. Investigators also conducted visual assessments in the study homes but did not find an association between visible mold and asthma. Do these studies mean that visual assessments are not useful for determining whether a mold problem exists? Do they indicate that complex sampling and analysis methods are required to identify home mold issues?

I would argue that ERMI is not ready for prime-time as a home assessment tool. In 2009, the Federal Register stated that, while ERMI is a “prototype research tool,” it has not been validated for wider use in identifying mold-contaminated environments. A 2012 industrial hygiene conference presenter noted that ERMI did not pass an internal 2009 EPA peer review. Indeed, the methods used to develop ERMI have not been subjected to external peer review. The DNA-based lab method on which ERMI (called MSQPCR) is based has not been subjected to internal and external laboratory tests needed to verify its precision and accuracy.

Reducing home moisture problems to minimize exposure to mold and other moisture-related toxins is a vital goal. Although the recent asthma study did not find an association between mold found through visual inspection and asthma development, a large body of literature suggests that water damage identified by home inspection is associated with increased asthma and respiratory disease risk. For example, the two articles referenced above indicate ERMI may have potential as a research tool, but trained eyes (and noses) are a more accessible and practical approach to identifying mold problems in homes.

Jill Breysse, CIH, MHS, Project Manager, joined NCHH in 1998. She currently leads the Aging Gracefully in Place project, working to improve elderly residents’ physical function and enhance their housing conditions so that they can safely age in place. Ms. Breysse has authored several peer-reviewed research articles evaluating healthy homes hazard assessment tools and interventions. She was the lead author of guidance on conducting health impact assessments for housing decisions and helped to develop the National Healthy Homes Standard, an evidence-based standard of care for existing owner-occupied and rental housing. Ms. Breysse holds a Master of Health Science in environmental health engineering from the Johns Hopkins Bloomberg School of Public Health and a Bachelor of Science in Chemistry from the University of Maryland.