title: Vapor intrusion attenuation factors relative to subslab and source, reconsidered in light of background data.
abstract: The basis upon which recommended attenuation factors for vapor intrusion (VI) have been derived are reconsidered. By making a fitting curve to the plot showing the dependence of observed indoor air concentration (c(in)) on subslab concentration (c(ss)) for residences in EPA database, an analytical equation is obtained to identify the relationship among c(in), css and the averaged background level. The new relationship indicates that subslab measurements may serve as a useful guide only if c(ss) is above 500 μg/m(3). Otherwise, c(in) is independent of c(ss), with a distribution in good agreements with other studies of background levels. Therefore, employing this screening value (500 μg/m(3)), new contaminant concentration attenuation factors are proposed for VI, and the values for groundwater-to-indoor and subslab-to-indoor air concentration attenuation factors are 0.004 and 0.02, respectively. The former is applied to examining the reported temporal variations of c(in) obtained during a long-term monitoring study. The results show that using this new groundwater-to-indoor air concentration attenuation factor also provides a reasonably conservative estimate of c(in).
authors.affiliation: MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou 310058, China; Institute of Environmental Science, Zhejiang University, Hangzhou 310058, China. Electronic address: Yijun_Yao@zju.edu.cn.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Yao
authors.affiliation: MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou 310058, China; Institute of Environmental Science, Zhejiang University, Hangzhou 310058, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wu
authors.affiliation: School of Engineering, Brown University, RI 02912, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Suuberg
authors.affiliation: Independent Researcher, Espoo, Finland.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Provoost
authors.affiliation: Halliburton Energy Services, Inc., Houston, TX 77032, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Shen
authors.affiliation: MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou 310058, China; Institute of Environmental Science, Zhejiang University, Hangzhou 310058, China.
authors.forename: Jianqing
authors.initials: J
authors.lastname: Ma
authors.affiliation: MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou 310058, China; Institute of Environmental Science, Zhejiang University, Hangzhou 310058, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
mesh_terms: D016902:Air Pollution, Indoor; D016208:Databases, Factual; D006798:Housing; D008962:Models, Theoretical; D012989:Soil Pollutants / Q000737:chemistry*; D014835:Volatilization; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D012989:Soil Pollutants; D014874:Water Pollutants, Chemical
keywords: Attenuation factors; Background concentration; EPA database; Subslab concentration; Vapor intrusion