PSI - Issue 22

António Curado et al. / Procedia Structural Integrity 22 (2019) 386–392 António Curado et. al / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 1. indoor radon, air temperature and relative humidity variation over one week – winter analysis.

Fig. 2. indoor radon, air temperature and relative humidity variation over one week – summer analysis.

In accordance with Fig. 1 and Fig. 2, indoor radon concentration stays above both specified limits: the Portuguese legal limit (300 Bq.m -3 ) and the WHO limit (100 Bq.m -3 ), both for winter and summer situations. On the other hand, values for indoor air temperature and relative humidity tend to increase during the occupation period. It is evident a direct correlation between radon levels and the air renovation occurred during occupation periods, both for winter and summer scenarios. The results show and indirect correlation between radon levels and air temperature, and a direct correlation between radon levels and relative humidity. 5. Radon risk assessment The calculation of the parameters AARC (Annual Average Radon Concentration), SD (standard deviation) and IED (Indoor Effective Dose), in accordance with Section 2, for the instrumented room (ground-floor office), is represented in Table 1. 10 administrative employees working 7 hours a day, during a normal working week, occupy the instrumented room. The monitoring campaign lasted one week (short-term measurements), both in winter and summer season.

Table 1. Statistical results for the monitored room. Season

Winter

Summer

ARC[Bq.m -3 ] SD [Bq m -3 ] IED [mSv/yr]

643 188

643 176

3.6

3.6