Civil Engineering Reference
In-Depth Information
Toxicity Issues: Radon
Fernando Pacheco Torgal
Abstract This chapter reviews literature on radon as a source of indoor air
contamination. It shows that post-construction remediation like soil depressur-
ization systems (SDS) seems to be more cost-effective than the use of protection
measures installed during construction like radon-barrier membranes which have a
significant failure rate. Since radon concentration is very dependent on the air
change rate (ACH), it is important to maintain adequate air ventilation. However,
in some situations, the cost of additional heating to eliminate the heat losses would
exceed the total costs of remediation by soil ventilation as much as eightfold. This
chapter also shows that there are optimum temperature and relative humidity
which minimize radon levels.
1 Introduction
Radon (
222
Rn) is a colorless, odorless radioactive gas that comes from the ground
in granitic-related areas but its source can also be from granite floor materials or
even from construction materials, thus polluting indoor air. Radon was identified
as a human lung carcinogen in 1986 by the WHO (Clement
2010
).
According to this organization, radon gas is by far the most important source of
ionizing radiation among those that are of natural origin. This gas constitutes the
second cause of death after lung cancer (WHO
2009
).
Evidence between indoor radon exposure and lung cancer was reported two
decades ago by Field et al. (
2003
). Most radon gas inhaled is immediately exhaled,
however, if decay occurs in the lungs, the resulting solid radioactive particles can
settle onto bronchial epithelial cells causing DNA damage (Chauhan et al.
2012
).
