title: Radon in indoor air of primary schools: determinant factors, their variability and effective dose.
abstract: Radon is a radioactive gas, abundant in granitic areas, such as in the city of Porto at the north-east of Portugal. This gas is a recognized carcinogenic agent, being appointed by the World Health Organization as the leading cause of lung cancer after smoking. The aim of this preliminary survey was to determine indoor radon concentrations in public primary schools, to analyse the main factors influencing their indoor concentration levels and to estimate the effective dose in students and teachers in primary schools. Radon concentrations were measured in 45 classrooms from 13 public primary schools located in Porto, using CR-39 passive radon detectors for about 2-month period. In all schools, radon concentrations ranged from 56 to 889 Bq/m(3) (mean = 197 Bq/m(3)). The results showed that the limit of 100 Bq/m(3) established by WHO IAQ guidelines was exceeded in 92 % of the measurements, as well as 8 % of the measurements exceeded the limit of 400 Bq/m(3) established by the national legislation. Moreover, the mean annual effective dose was calculated as 1.25 mSv/y (ranging between 0.58 and 3.07 mSv/y), which is below the action level (3-10 mSv). The considerable variability of radon concentration observed between and within floors indicates a need to monitor concentrations in several rooms for each floor. A single radon detector for each room can be used, provided that the measurement error is considerably lower than variability of radon concentration between rooms. The results of the present survey will provide useful baseline data for adopting safety measures and dealing effectively with radiation emergencies. In particular, radon remediation techniques should be used in buildings located in the highest radon risk areas of Portugal. The results obtained in the current study concerning radon levels and their variations will be useful to optimize the design of future research surveys.
authors.affiliation: Institute of Science and Innovation on Mechanical Engineering and Industrial Management, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal. jmadureira@inegi.up.pt.
authors.forename: Joana
authors.initials: J
authors.lastname: Madureira
authors.affiliation: Institute of Science and Innovation on Mechanical Engineering and Industrial Management, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
authors.forename: Inês
authors.initials: I
authors.lastname: Paciência
authors.affiliation: Institute of Science and Innovation on Mechanical Engineering and Industrial Management, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Rufo
authors.affiliation: Faculty of Medicine of University of Porto, Al. Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.
authors.forename: André
authors.initials: A
authors.lastname: Moreira
authors.affiliation: Institute of Science and Innovation on Mechanical Engineering and Industrial Management, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
authors.forename: Eduardo
authors.initials: E
authors.lastname: de Oliveira Fernandes
authors.affiliation: Natural Radioactivity Laboratory, Department of Earth Sciences, University of Coimbra, Rua Sílvio Lima, 3030-790, Coimbra, Portugal.
authors.forename: Alcides
authors.initials: A
authors.lastname: Pereira
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D006801:Humans; D011174:Portugal; D011834:Radiation Monitoring / Q000379:methods; D011886:Radon / Q000032:analysis*; D012574:Schools
chemical_list: D000396:Air Pollutants, Radioactive; D011886:Radon
keywords: Effective dose; Indoor air quality; Indoor radon; Primary schools; Schoolchildren; Variability