Analysis of the spatial distribution of the indoor radon concentration in school's buildings in Plovdiv province, Bulgaria

• Published in: Building and environment 2021-10, Vol.204, p.108122, Article 108122
• Main Authors: Ivanova, K., Stojanovska, Z., Djunakova, D., Djounova, J.
• Format: Article
• Language: English
• Subjects: Buildings; Construction; Indoor air pollution; Indoor environments; Indoor radon; Kolmogorov-Smirnov test; Mathematical analysis; Mathematics; Municipalities; Plovdiv-Bulgaria; Quality control; Radon; Radon levels; School buildings; Schools; Spatial analysis; Spatial distribution; Spatial variation; Spatial variations; Standard deviation
• ISSN: 0360-1323; 1873-684X
• DOI: 10.1016/j.buildenv.2021.108122

This paper presents an evaluation of the indoor radon spatial variation between and within school buildings. Radon measurements were carried out in 331 rooms of 16 school buildings in 5 municipalities of Plovdiv province, Bulgaria. They were performed with CR-39 nuclear track detectors exposed over an 8-month period from September 2018 to April 2019. The arithmetic and geometric means together with corresponding standard deviation and geometric standard deviations of the indoor radon concentration were 160 ± 175 Bq/m3 and 108 */2.35 Bq/m3, respectively. The best data fit was achieved with a Weibull 3-parameter function (Kolmogorov-Smirnov test, p = 0.2916). The effect of the school location and various building characteristics on the indoor radon concentration distribution within a province was investigated. The analyses showed that the factor “year of building construction”, which is in general related with the technical condition of the building, imposed the highest impact on the indoor radon concentration difference between schools. The vertical and horizontal components of the indoor radon spatial variability within a school were analysed as well. The results concerning the radon variation within schools could be used to optimize future radon school surveys. In this paper, quality control for indoor radon measurement procedures and radon health impact assessments was included. •The radon concentration spatial distribution in school buildings according to different factors was assessed.•Quality control verification in this study was performed with duplicate detectors, which is a good practice to ensure high-quality results.•The analysis of the results revealed significant differences in CRn between and within the school buildings.•The analysis of the CV,% and GSD for the classroom by classroom and office by office variation indicated that they were similar on the ground floor and first floor.•The vertical room by room variations in CRn were much less pronounced than the horizontal variations, which were much more notable among the school buildings than within the buildings themselves.