北京地区室外氡及氡子体浓度水平及变化规律研究

目的 了解北京地区室外环境空气中氡及氡子体浓度水平，分析其变化规律及影响因素。方法 采用氡及氡子体浓度在线连续测量装置，测量周期为60 min，在北京地区不同方位的3个观测点，进行为期1年的长期连续测量。结果 北京地区室外空气中氡浓度年平均值为（10.9±4.9）Bq/m³，氡子体浓度（平衡当量氡浓度）年平均值为（5.8±3.4）Bq/m³、平衡因子年均值为0.52±0.19；观测到氡及氡子体浓度有类似的日变化规律，最高值出现在清晨时段，最低值出现在下午黄昏时段、没有观测到平衡因子有日变化规律；氡及氡子体浓度月平均值在4~5月份较低，在11、12月和次年1月份相对较高。结论 为期1年的在线连续测量结果表明，北京地区室外空气中氡及氡子体浓度年均值与世界均值水平接近，低于抓取式采样测量给出的我国典型值；氡及氡子体浓度日变化规律与国内外类似测量研究结果相同，季节变化规律具有北京地区局地气候影响特征。

Study on outdoor radon and its progeny concentration level and variation pattern in Beijing area

Objective To understand the concentration level of radon and its progeny in outdoor air in Beijing area and to analyze the related variation pattern and influencing factors. Methods The continuous measurement device for radon and its progeny concentration is used for the one-year continuous measurement at three points in different directions in Beijing area. Results The annual concentration average value was (10.9±4.9) Bq/m³ for radon and (5.8±3.4) Bq/m³ for its progeny (equilibrium equivalent radon concentration EEC) in outdoor air in Beijing with the annual average value of 0.52±0.19 for equilibrium factor F. Clear diurnal variations of the concentrations of radon and its progeny was observed. Conclusions The result of one-year continuous measurement show that the concentrations of radon and its progeny in the outdoor air in Beijing area are close to the world average, lower than the typical values in China given by grab sampling measurement. The daily variation pattern of radon and its progeny concentrations is similar to those at home and abroad. The seasonal variation pattern features local climate in Beijing.