An example is HS7 which presented a
greater concern for non-cancer effects even though it was not the
most polluted site. Whereas HS5 appeared to be among the least
polluted yet presented a high THRI value. IAQ Cancer Risk Indicator
(CRI) for each indoor and outdoor site was also calculated (see
Fig. 3) considering the VOCs that exhibit carcinogenic activity:
benzene, ethylbenzene, naphthalene, and tetrachloroethylene (see
UR values in Table 3). The indoor/outdoor comparison showed that
the indoor CRI was equal to or slightly greater than the corresponding
outdoor level. Benzene and naphthalene were the principal
contributors to the CRI with the exception of the indoor value
for HS7 where the tetrachloroethylene contribution was the highest,
approximately LCR 8 105, and the indoor value for HS3
where ethylbenzene reached LCR 7.88 105. This finding shows
that the possible cancer risk present in the monitored environments
was mainly linked to the input/intrusion of VOCs from
outdoor areas.