Issue link: https://hi.iaq.net/i/248503
www.epa.gov/iaq/moisture • Prolonged damp conditions can lead to the colonization of building materials and HVAC systems by molds, bacteria, wood-decaying molds and insect pests (e.g., termites and carpenter ants). Details of the results of this review were published in a 2004 report, Damp Indoor Spaces and Health.4 It is also important to note that immuno-compromised individuals, such as some categories of hospital patients, are at increased risk for fungal colonization and opportunistic infections.5 • Chemical reactions with building materials and components can cause, for example, structural fasteners, wiring, metal roofing and conditioning coils to corrode and flooring or roofing adhesives to fail. After the publication of the IOM report, a study by Lawrence Berkeley National Laboratory concluded that building dampness and mold raise the risk of a variety of respiratory and asthma-related health effects by 30 to 50 percent.6 A companion study by EPA and Berkeley Lab estimated that 4.6 million cases of asthma, 21 percent of the 21.8 million cases of asthma in the U.S. at that time, could be attributed to exposure to dampness and mold in homes.7 • Water-soluble building materials (e.g., gypsum board) can return to solution. • Wooden materials can warp, swell or rot. • Brick or concrete can be damaged during freezethaw cycles and by sub-surface salt deposition. • Paints and varnishes can be damaged. • The insulating value (R-value) of thermal insulation can be reduced. Moisture Damage in Buildings In addition to causing health problems, moisture can damage building materials and components. For example: The following photos show some of the damage that can result from moisture problems in buildings. Figure 1-1 Mold growing on the surface of painted gypsum board and trim. Long-term high humidity is the source of the moisture that allowed the mold growth. All of the walls experienced similar near-condensation conditions. Consequently, the mold growth is widespread rather than concentrated in a single damp area. 4 Institute of Medicine (2004) Damp Indoor Spaces and Health. http://www.iom.edu/Reports/2004/Damp-Indoor-Spaces-and-Health.aspx. Accessed November 6, 2013. 5 Institute of Medicine (2004) Damp Indoor Spaces and Health. http://www.iom.edu/Reports/2004/Damp-Indoor-Spaces-and-Health.aspx. Accessed November 6, 2013. W. J. Fisk, Q. Lei-Gomez, M. J. Mendell (2007) Meta-analyses of the associations of respiratory health effects with dampness and mold in homes. Indoor Air 17(4), 284-295. doi:10.1111 /j.1600-0668.2007.00475.x 6 7 D. Mudarri, W. J. Fisk (2007) Public health and economic impact of dampness and mold. Indoor Air 17 (3), 226–235. doi:10.1111 /j.1600-0668.2007.00474.x 2