Risk Assessment And Control Scheme Of Radon Pollution And Radiation In Public Buildings

In recent years,the number of patients suffering from lung cancer caused by radon pollution radiation increases year by year,and reducing indoor radon pollution radiation has become a focus of attention.Since the research on indoor radon concentration started late in China,the research on indoor radon concentration in public buildings is not comprehensive enough,there are few effective measures to reduce radon.Therefore,in this paper,indoor radon concentration of various types of public buildings was measured by means of instrument measurement.The law of radon concentration was analyzed,the variation of indoor radon concentration in spring and winter was studied,the influencing factors of indoor radon concentration were explored,and the relationship between radon content and distribution in soil and indoor radon concentration in public buildings was measured.Based on the risk assessment model,the effective measures to control radon are put forward.The main research work and conclusions are as follows:(1)By measuring indoor radon concentration in public buildings on campus,it is found in this paper that the concentration of radon in the indoor library and heat pump machine room on the negative floor is higher than that in the classroom on the first floor of civil and public teaching building,and higher than that in the hall of canteen and library on the first floor.The average indoor radon concentration on the negative first floor is 108.5Bq/m3 and the average indoor radon concentration on the first floor of the teaching building is 71.5Bq/m3,both higher than the average indoor radon concentration in China.(2)In this paper,indoor radon concentration in public buildings outside the school is compared,and the results are as follows: indoor radon concentration in hospitals > quick hotels > windowless hotels > star hotels > train stations and airport waiting halls.It is found from the data that the average indoor radon concentration of36.5Bq/m3 in hospitals decorated with a large amount of marble and 34.3Bq/m3 in low-rise hotels with obvious cracked walls are higher than that of other types of buildings.(3)According to the measurement results of radon content in campus soil,the average radon content in campus soil is 12731Bq/m3,which is far higher than the average level of radon content in China,and the radon content in most of the detection sites is at the second level of potential harm.Soil radon content is also the main source of indoor radon concentration in low-rise buildings.Higher soil radon content will lead to higher indoor radon concentration and directly affect indoor radon concentration in surrounding public buildings,this is also the reason why the radon concentration on the negative first floor and the first floor of public buildings on campus is higher than the average indoor radon concentration in China.In the same area,there is a difference of 12610Bq/m3 in soil radon content between the two detection points.The reason is that the difference in soil surface texture leads to the difference in radon exhalation rate on soil surface,which leads to the difference in soil radon content.(4)Through continuous laboratory monitoring,it is found that indoor temperature and humidity have a great impact on indoor radon concentration.By comparing the indoor radon concentration in the laboratory in spring and winter,it can be concluded that under the influence of heating and season,Compared with spring,indoor humidity decreased by 42.5% in winter and indoor temperature increased by 4℃,resulting in a 47% decrease in average radon concentration in winter and a 46% decrease in peak radon concentration.However,in buildings without heating facilities,Indoor humidity does not change significantly in winter compared with spring,but the temperature will decrease,so the average indoor radon concentration in winter is higher than that in spring.In addition,weather,indoor envelope structure and wallpaper material are all factors affecting indoor radon concentration,among which indoor insulation board floor and waterproof and moisture-proof wallpaper have better radon resistance effect.(5)From the calculation of laboratory radiation dose,it can be concluded that the annual effective dose per capita in the laboratory is HE= 4.3ms V,which is far higher than the prescribed limit in China and has serious radiation harm.The risk assessment of the laboratory was carried out through the risk assessment model,and the results showed that non-smoking teachers and students in the laboratory were in the secondary risk;Teachers and students who smoke and have lung disease are at grade 3 risk.(6)This paper explores soil radon,indoor radon concentration in different public buildings,variation characteristics of radon and its influencing factors.Several effective measures to control radon are proposed,such as building site selection,decoration material selection,natural ventilation optimization and indoor temperature and humidity control.