| Objective(1) Study the distribution characteristics of radionuclides at haze days. Analyzed and discussed the variation rule of radionuclides caused by haze weather. Elucidate the mechanism of aerosol combined with radionuclides.(2) Estimate effective dose by concentrations of radon and its daughters, and population exposure time. Evaluate the risks of radiation for the exposed population.Methods(1) Measuring Select Dushu Lake Campus of Soochow University Medical Building roof as experimental monitoring points. Monitor radionuclide concentration with EQF3120, radon and its daughters measuring instrument.(2) Data Collection Collect air quality monitoring data in real-time of air stations of Soochow University Dushu Lake Campus from environmental monitoring stations of Suzhou Industrial Park.(3) Statistical Analyse Do statistical description and analysis for the two types of data using Excel2013, SPSS16.0 and SAS8.0 software. Includes correlation analysis, principal component analysis and canonical correlation analysis.(4) Dose Estimation and Comparison Estimate the effective dose of radon and its progeny at lung under different Air Quality Index(AQI) by radon exposure dose conversion formula recommended by ICRP. Compare effective dose at different AQI levels. Assessment the degree of harm to human bady resulted from radon exposure at haze weather. Clear relationship between severity of fog and haze and exposure risk to the population.Results(1) Air quality concentration in descending order: CO>O3>PM10>PM2.5> NO2 >SO2. The concentration of PM10 is 0.126 mg/m3; concentration of PM2.5 is 0.079 mg/m3. The ratio between PM2.5 and PM10 as 0.63; PM2.5, PM10,NO2 and SO2 has a good correlation coefficient with the principal components,also between of them. PM10 and PM2.5 both have a very good correlation wi th the principal component and the correlation coefficient were 0.922 and 0.952;O3 negatively correlated with the main ingredient.(2) As the AQI increases, three bound radon progeny concentrations were increased. Concentration changing of PM2.5 has a similar trend with three kinds of bound radon progeny.(3) Bound radon progeny have correlated relationships with NO2, SO2, O3, PM10 and PM2.5, and the correlation coefficient with the PM2.5 greater than that with PM10. Correlation coefficients between each radon progeny with PM10, PM2.5, SO2, NO2 were in descending order of 214Bi>214Pb>218Po.(4) As the AQI increases, radon-induced lung area exposed effective dose increases. Effective dose of radon exposure caused by haze weather is 2.2 times than that of no haze days.Conclusions(1) Air Pollution in Suzhou Industrial Park, the main industry both automobile. Fine particles are the main pollutants, and pollution is more serious in winter. The haze days are relative concentrated.(2) Radon concentration was significantly higher. AQI and bound radon concentrations were positively correlated. The greater of AQI, the more serious of haze, the higher of concentration of bound radon progeny.(3) The survey found that, there is no significant correlation between AQI and unbound concentration of radon progemy.(4) The more severe of haze weather, the higher concentration of bound radon progeny. And a greater health risks for exposed population. So, haze will increase the health risks of the exposed population.(5) Recommend that the population outdoor work and life should wear masks which can filter particles aerodynamic diameter range 0.01~3.0 μm at hazy days. |
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