Investigation and analysis on seasonal variations of indoor 222Rn and 220Rn concentrations in Longdong district,Gansu Province / 中华放射医学与防护杂志

ABSTRACT

Objective To study the seasonal variation of indoor 222Rn and 220Rn concentrations in Longdong district,Gansu Province.Methods A total of 44 houses from 5 different types of raw soil architectures and 5 ordinary brick houses from a typical area were selected in Longdong district,Gansu Province in China.The LD-P discriminative 222Rn and 220Rn detectors were used to measure the indoor concentrations of 222Rn and 220Rn during four seasons in one year.Results The indoor concentrations of 222Rn showed a significant seasonal variation,which varied with different types of houses.222Rn concentrations of ordinary brick houses,soil brick houses and the cave dwellings were higher in winter and autumn and lower in summer.The average concentrations of 222Rn were 55.3-90.3 Bq/m3 in winter,36.4-65.7 Bq/m3 in spring,35.6-63.9 Bq/m3 in summer,and 60.7-87.2 Bq/m3 in autumn.For cave dwellings,open-cut cave dwellings and the underground cave dwellings,222Rn concentrations were higher in summer and autumn,and lower in winter and spring.The average concentrations of 222Rn ranged from 139-184 Bq/m3 in winter,135-199 Bq/m3 in spring,179-252 Bq/m3 in summer,172-242 Bq/m3 in autumn.The seasonal variation of indoor 220Rn was basically consistent in six types of houses,and lower in winter and spring and highest in autumn.The average concentrations of 220Rn ranged from 43.4-64.3 Bq/m3 in winter,60.6-537 Bq/m3 in spring,77.7-792 Bq/m3 in summer,63.2-1077 Bq/m3 in autumn.The indoor concentrations of 222Rn and 220Rn were different among different types of houses,and they were generally higher in type of raw soft architectures than in that of ordinary brick houses.Conclusions 222Rn concentrations indoors showed a significant seasonal variation and varied with different types of houses.