the home (i.e., basement) as temperatures increase will raise the potential for increased
radon exposure and to other indoor air pollutants (e.g., molds, carbon dioxide, etc.)
Weatherization and Energy Efficiency
There is widespread, perhaps erroneous in many cases, belief that increased
weatherization and energy efficiency of homes significantly contributes to increased
residential radon concentrations. For example, the latest ATSDR (2010) statement on
radon includes the following statement, “In indoor locations, such as homes, schools, or
office buildings, levels of radon and radon progeny are generally higher than outdoor
levels and may be particularly high in some buildings, especially in newer construction
that is more energy-efficient.” However, in their book, “Radon’s Deadly Daughters”,
Edelstein and Makofske (1998) label the belief that radon concentrations in energy
efficient homes are differentially elevated as compared to other homes, “the myth of the
tight house”. They noted that high insulation rates as well as energy efficient homes,
relying on several studies published primarily during the 1980s to support their view,
have limited influence on increased radon concentrations. However, the authors
concede that tightening homes may increase radon concentrations for homes that have
significant sources of indoor radon sources (e.g., waterborne radon, building materials).
Since 1990, numerous studies noted that past and current energy efficiency
measures do not necessarily increase radon concentrations (EPA 1994, Chi and
Laquatra 1990, Mullen and Nevissi 1990). Nonetheless, continued uncertainty remains
about the impact of weatherization and energy efficiency on residential radon
concentrations. In late fall of 2009, Senator Mark Udall wrote to the Secretary of
Energy, Steven Chu, and EPA Administrator, Lisa Jackson, expressing his concern
about the Department of Energy’s ongoing weatherization program in regard to indoor
pollutants, including radon (attached). In a March 2010 letter of response to Senator
Udall, Steven Chu and Lisa Jackson indicated that both the DOE and EPA will assure
that weatherization practices will do no harm and will evaluate the effect of
weatherization on indoor radon (attached). If energy efficiency and weatherization
guidelines include consideration of air exchange rates and ventilation, climate change
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