Abstract: To address the notable effects of humidity on radon measurement using activated charcoal canister, diffusion barrier and activated charcoal with high adsorption coefficient were adopted to develop an activiated charcoal canister sampleradapted for hight hunidity conditions. Under an ambient humidity of 95% and a sampling time of 2—5 days, the sensitivity and error of the radon measurements comply with the requirements of “Code for Indoor Environmental Pollution Control of Civil Building Engineering” (GB 50325). Providing with a sampling time of 72 h, the sampler's lower limit of radon detection is 10 Bq/m³.

Key words: radon concentration, activated charcoal canisters, diffusion barrier, humidity