RESUMO
A nationwide radon survey was conducted to provide data on the annual average indoor radon concentration in Korean homes. This survey also provided data on the variation of radon concentration with season, house type, and building age. The arithmetic mean (AM) of annual radon concentration in Korean homes was 53.4 +/- 57.5 Bq m(-3). The indoor radon concentration showed a lognormal distribution with a geometric mean (GM) and its standard deviation (GSD) of 43.3 +/- 1.8 Bq m(-3). The radon concentrations in the traditional Korean-style houses were about two times higher than those in apartments and row houses. The average annual outdoor radon concentration was 23.3 Bq m(-3). The average annual effective dose to the general public from radon was 1.63 mSv y(-1).
Assuntos
Poluentes Radioativos do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental/métodos , Habitação/estatística & dados numéricos , Radiometria/métodos , Radiometria/estatística & dados numéricos , Radônio/análise , Radiação de Fundo , Materiais de Construção , Coleta de Dados , Habitação/classificação , Coreia (Geográfico) , Modelos Biológicos , Doses de Radiação , Radiometria/instrumentação , Reprodutibilidade dos Testes , Estações do Ano , Sensibilidade e Especificidade , Fatores de Tempo , Topografia Médica/métodos , VentilaçãoRESUMO
Based on hourly means of exposure rate between August 2000 and July 2001 at nine Regional Radiation Monitoring Stations (RRMS) in Korea, we analyzed spatio-temporal characteristics of exposure rate. The mean and fluctuations of exposure rates were 99 and 3.8 nGy h(-1), respectively. The hourly exposure rate over 9 RRMS indicated a diurnal pattern with the exposure rates reaching a maximum between 5:00 and 8:00 a.m. in the early morning and a broad minimum between 4:00 and 10:00 p.m. in the afternoon. The fluctuations of exposure rate in the inland areas were less than 3.2 nGy h(-1), and those of exposure rate in coastal areas were larger than 3.9 nGy h(-1). The frequency distribution of exposure rates had one peak around the mean and was to be skewed to the right or positively skewed and its tails were fatter than those of a normal distribution. The interrelations of exposure rates at each station generally decreased with the distance between the stations. Empirical orthogonal function (EOF) analysis showed that almost all (99.9%) of exposure rate fluctuations were described by simultaneous variations. The spatial distribution of the first EOF modes of actual, low-pass (periods longer than one month) and high-pass (periods shorter than one month) exposure rate series were similar to each other.
