Background: It’s difficult to evaluate the radon prevention effect because of the short operating time of measuring instrument under the circumstances of high humidity in underground construction. Purpose: A new rapid method to evaluate the radon prevention efficiency of underground construction was introduced. Methods: The radon concentrations before and after shielding operation were determined

and according to the regularity of radon decay

the shielding rate can be calculated. Results: The results showed that radon shielding rate in underground construction remains generally stable with variation of time

and the actual relatively standard deviation was 3.95%. So the rapid determination and evaluation of radon preventing effect under special conditions in underground construction can be realized by taking shielding rate in a short time for the final shielding rate. Compared with those by the local static method in ground lab

the results were similar. Conclusion: This paper provided a prompt

accurate and practicable way for the evaluation of radon prevention in underground construction

having a certain reference value. Abstract