| Radon is ubiquitous in the air,colorless and odorless.It is easy to enter the human body by breathing,and has radioactivity.It will damage the human lung,respiratory tract and other tissues,so it is easy to induce lung cancer,respiratory tract and other diseases.According to statistics,about 77%of radon in the air is released from the surface of the land.With the rapid growth of China's economy,people's living standards are constantly improving,and the quality of living environment is becoming more and more important.In this paper,the physical and chemical properties,sources,hazards and characteristics of radon are comprehensively expounded,and the formation of radon in soil and the factors affecting the concentration of radon in soil are analyzed and discussed.The distribution of radon in soil is simulated,and the general differential equation of radon distribution is given.At the same time,the distribution of radon in soil cover is simulated.The physical model is given,and the necessary solution of the mathematical model is given.Finally,the simulation results are displayed through concentration slice and depth change maps.(3)The status of Yangzhou City,a data acquisition area,was studied,and the instruments and methods needed to be collected were described in detail.Geographical overview in the region,including geological generalization in the region,was studied.Including topography,geomorphology,geological structure,meteorology,hydrology,geotechnical types and other related information.At the same time,the data of Yangzhou were collected by radon testing instrument.(4)The spatial distribution of radon in the east-west,north-south and whole soil of Yangzhou City was analyzed and evaluated in detail by using GIS spatial analysis technology and combining with the geological characteristics and geomorphological conditions of Yangzhou City.The distribution of radon concentration in the East and west of Yangzhou is basically the same,with an average value of 1226 Bq/m3.This shows that people in Yangzhou have more development activities and a longer time in the East and west.Shallow soil is based on the later miscellaneous fills,and changes are almost the same under the action of nature.The distribution of radon concentration in the north-south direction of Yangzhou is discrete relative to the East-West direction,with an average value of 1210 Bq/m3.In the North-South direction,the development and utilization of land in the central part of Yangzhou City is the most and the earliest.Therefore,shallow soil changes a lot due to people's activities and natural effects,and the soil quality is mainly silt.It is very loose and does not have the ability to conserve radon in soil.(5)The theoretical model was compared with the tested results.The distribution of the theoretical values was in good agreement with the experimental results.The arithmetic mean of the theoretical calculations was 1334.15 Bq/m3,the measured arithmetic mean was 1346.25 Bq/m3,and the relative error between them was relatively small(relative error was 0.90%).In this paper,the spatial interpolation method was used to analyze the content of radon in soil,which greatly simplified the study of the distribution of soil radon in Yangzhou and would provide data support for the scientific planning of city.Furthermore,this study had important practical and scientific significance in improving the quality of life people and improving the urban environmental quality of city. |
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