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Journal of Environmental and Public Health
Volume 2011, Article ID 242457, 11 pages
Research Article

Geographic Distribution of Environmental Relative Moldiness Index Molds in USA Homes

1National Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
2Consolidated Safety Services, Dynamac Corporation, Cincinnati, OH 45268, USA
3U.S. Department of Housing and Urban Development, Washington, DC 20410, USA
4Environmental Sciences Group QuanTech, Arlington, VA 22201, USA

Received 21 June 2010; Revised 4 February 2011; Accepted 11 March 2011

Academic Editor: Stuart A. Batterman

Copyright © 2011 Stephen Vesper et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. The objective of this study was to quantify and describe the distribution of the 36 molds that make up the Environmental Relative Moldiness Index (ERMI). Materials and Methods. As part of the 2006 American Healthy Homes Survey, settled dust samples were analyzed by mold-specific quantitative PCR (MSQPCR) for the 36 ERMI molds. Each species' geographical distribution pattern was examined individually, followed by partitioning analysis in order to identify spatially meaningful patterns. For mapping, the 36 mold populations were divided into disjoint clusters on the basis of their standardized concentrations, and First Principal Component (FPC) scores were computed. Results and Conclusions. The partitioning analyses failed to uncover a valid partitioning that yielded compact, well-separated partitions with systematic spatial distributions, either on global or local criteria. Disjoint variable clustering resulted in seven mold clusters. The 36 molds and ERMI values themselves were found to be heterogeneously distributed across the United States of America (USA).