Influence of architectural style on indoor radon concentration in a radon prone area: A case study

- Surface radon exhalation rate from soil in itself was unable to explain indoor radon.
- Architectural style had a significant influence in the selected radon prone area.
- New dwellings have higher indoor radon concentrations than Traditional ones.
- Refurbished Traditional dwellings have higher indoor radon than Non-Refurbished.

Indoor radon is a major health concern as it is a known carcinogenic. Nowadays there is a trend towards a greater energy conservation in buildings, which is reflected in an increasing number of regulations. But, can this trend increase the indoor radon concentration? In this paper, we selected a radon prone area in Spain and focused on single-family dwellings constructed in a variety of architectural styles. These styles ranged from 1729 up to 2014, with varying construction techniques (from local resources to almost universally standard building materials) and regulations in force (from none to the Spanish regulation in force). The 226Ra concentrations in soil and surface radon exhalation rates were rather similar in this area, mean values ranging 70-126 Bq/kg and 49-100 mBq/m2·s, respectively. Indoor radon concentration was generally greater than the contribution from soil exhalation (surface exhalation rates), especially in New dwellings (1980-2014). Its concentration in dwellings built in the Traditional style (1729-1940) was significantly lower than in the new houses. This can be consequence of the air tightness of the dwellings as a consequence of the different regulations in force. In the period covered by the Traditional style, there was no regulation in force, and dwelling had loose air tight. Whereas in recent times, there are mandatory regulations assuring a better air tightness of the buildings. Refurbishment of Traditional dwellings also seems to increase the indoor radon concentration, as they must also comply with the regulations in force.

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