我国不同类型地下工程中的氡水平

为了解我国地下工程内氡的浓度水平及其可能对人体产生的危害,采用核固体径迹法,在不同季节对全国23个城市的234个地下工程测点的氡浓度进行了测量。根据工程的建筑类型及用途的不同,将所有被测工程分为坑道、干道(包括掘进式地道工程)、地下室(高层建筑地下室和掘开式工程)和停车场四类,各类工程的氡浓度平均值分别为327、619、96.9、59.1 Bq.m-3。对于不同山体岩性的坑道,氡浓度值由高到低的顺序是花岗岩>凝灰岩>石英砂岩>石灰岩>安山玢岩。比较各类工程不同季节的氡浓度,得出,停车场氡浓度季节变化不大,其它三类工程都有氡浓度夏季明显高于冬季的特点,而且通风差的未使用的坑道和干道比使用中的同类工程具有相对高的氡浓度夏/冬比值。

RADON LEVELS IN DIFFERENT TYPES OF UNDERGROUND BUILDINGS IN CHINA

For surveying the radon and its radiation to people in underground buildings in China,using solid state nuclear detectors,a survey of the air radon levels in 234 underground buildings in 23 cities of China was carried out during spring,as well as in summer and winter.Studied underground buildings were classified to four types in building style: saps,tunnels,basements and parking garages.The radon concentrations in saps,tunnels,basements and parking garages are 327,619,96.9,59.1(Bq·)m~(-3),respectively.For saps with different geological formation rocks.The sequence of rocks in the saps in which radon concentrations vary from high to low is: granite> tuff > quartz sandstone > limestone > andesitic porphyry.There is no clear radon variation in garages,while in saps,tunnels and basements,radon concentrations in summer are higher than those in winter.Saps and tunnels have higher summer/winter ratios,higher in closed underground buildings than in unclosed underground buildings.