Environmental assessment of radon levels in Cyprus

Purpose - Radon is responsible for approximately 50 per cent of public exposure to environmental radiation. The purpose of this paper is to quantitatively assess indoor radon levels in Cyprus. Design/methodology/approach - In total, 500 passive radon detectors were used to estimate radon levels in the areas of Nicosia (capital), Paphos, Nisou and Famagusta. A total of 240 different public and private buildings were randomly selected in the above districts and two passive radon detectors were placed inside each building. The detectors were collected on average, three months following placement. Findings - The average radon level from all passive detectors was 53.7 and 49.2 Bq/m(3) after excluding the seven highest values. The two highest measurements were observed in Paphos, Tsada-Kili elementary school (429 Bq/m(3)) and Emba, Paphos district (410 Bq/m(3)), respectively. Differences were also seen in public buildings compared to private buildings (p = 0.058). In addition, rural buildings had higher radon levels compared to urban buildings (p = 0.001). Predictive multilevel regression models for logarithmic radon levels were employed and differences were seen on point estimates regarding building- and district-level radon measurements. Most of the random variability observed was due to building-level variation. Practical implications - Residents from different geographic areas in Cyprus are reassured about the safety of indoor radon levels in public and private buildings. Originality/value - The estimation of indoor radon levels was done by the optical microscopy technique using a specific mathematical formula. Observed radon levels do not raise concern regarding residents' radon exposure in Cyprus. Paphos district and Nisou area may require further investigation.