Geosyntec Consultants, Inc. , Toronto , Ontario M8X 2X9 , Canada.
Geosyntec Consultants, Inc. , Oakland , California 94607 , United States.
Environ Sci Technol. 2018 Aug 7;52(15):8438-8445. doi: 10.1021/acs.est.8b01106. Epub 2018 Jul 13.
A new method is presented for calculating a building-specific subslab to indoor air attenuation factor for use in assessing subsurface vapor intrusion to indoor air. The technique includes (1) subslab gas extraction with flow and vacuum measurements and mathematical modeling to characterize the bulk average vertical gas conductivity of the floor slab, (2) monitoring of the ambient pressure gradient across the floor slab with a micromanometer, (3) calculating the volumetric flow of soil gas into the building ( Q), and (4) dividing Q by the building ventilation rate ( Q) to calculate a building-specific attenuation factor. Sample calculations using order statistics from 121 individual tests are comparable to the U.S. Environmental Protection Agency empirical attenuation factors for residential buildings and the U.S. Navy empirical attenuation factors for commercial/industrial buildings. A case study of a commercial building shows encouraging agreement between the attenuation factors calculated via this method and via conventional subslab and indoor air sampling.
提出了一种新的方法来计算特定于建筑物的次层板至室内空气衰减因子，用于评估地下蒸气侵入室内空气的情况。该技术包括：（1）采用流量和真空测量以及数学建模对地板板的整体平均垂直气体传导率进行次层板气体抽取；（2）用微压计监测地板板上的环境压力梯度；（3）计算土壤气体流入建筑物的体积流量（Q）；（4）将 Q 除以建筑物通风率（Q），以计算特定于建筑物的衰减因子。使用 121 个单独测试的有序统计数据进行的示例计算结果与美国环保署针对住宅建筑的经验衰减因子和美国海军针对商业/工业建筑的经验衰减因子相当。商业建筑的案例研究表明，通过这种方法计算的衰减因子与传统的次层板和室内空气采样计算的衰减因子之间存在令人鼓舞的一致性。
