Environmental assessments on schools located on or near former industrial facilities: feedback on the use of attenuation factors for prediction of indoor air quality

Abstract : As part of 2nd and 3rd French National Environment and Health Action Plan, soil environmental assessments were carried at national level on schools built on or near past industrial facilities. It aims at evaluating if the soil, drinking water and/or air quality has been altered by those former activities. Environmental assessment included selection and evaluation of relevant exposure pathways using evidence-based information (industrial activities description, site history, school facilities, nature of potential contamination and analysis of relevant compounds and media). The French Ministry of Environment has entrusted the French Geological Survey (BRGM) with the task of delegated contracting authority to undertake organization of the environmental assessments and to ensure the homogeneity of the action and costs control at national level. The present work focuses on the evaluation of school’s indoor air quality that may be altered due to vapor intrusion and is based on data from 35 school sites spread across 9 regions allowing calculation of 599 dilution factors all compounds included. It is a feedback on the use of attenuation factors for vapor intrusion assessment. Risk assessment related to vapor intrusion uses the following three phases protocol: (i) determination of the presence of potential volatile compounds according to reported past industrial activities, (ii) analysis of soil gas multiplied by a relevant attenuation factor to estimate indoor air quality, (iii) sampling of indoor air if estimated air quality is above indoor air guidelines (toxicity reference values). Attenuation factors are used in phase 2 to warrant further analysis in the indoor air. Attenuation factors are chosen according to the school facilities and the media analyzed (soil gas or subslab gas). This choice is based mainly on US EPA’s feedback on vapor intrusion (US EPA, 2015) and models from Johnson-Ettinger (1991). However, differences in climate between US and France as well as differences in facility uses (air conditioning) or construction type (residential versus schools) may bring differences in vapor attenuation and therefore may induce different values of attenuation factors. Feedback of attenuation factors included design, elaboration and implementation of a specific database and statistical treatment of data. The database allows input of building characteristics and soil gas sampling and analysis parameters such as temperature, slab thickness and quality, compounds concentration as well as data pairing (indoor air/soil gas) for calculation of attenuation factor. The present work provides a statistical analysis of the data stored in this database. Data below quantification limit as soil or subslab were kept in the database but removed from the data treatment since they did not account for any vapor intrusion pathway. Data analysis focuses on 9 compounds (petroleum hydrocarbons and chlorinated solvents) and on the calculation of 599 attenuation factors for these selected compounds. Statistical analysis is still currently carried out and further results and conclusion will be included.
Type de document :
Communication dans un congrès
AquaConsoil, Jun 2017, Lyon, France. 2017
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Contributeur : Virginie Derycke <>
Soumis le : mardi 28 février 2017 - 11:27:34
Dernière modification le : samedi 24 juin 2017 - 01:07:39


  • HAL Id : hal-01478597, version 1



Virginie Derycke, Hubert Leprond, Aline Coftier, Mathilde Scamps, Clément Zornig, et al.. Environmental assessments on schools located on or near former industrial facilities: feedback on the use of attenuation factors for prediction of indoor air quality. AquaConsoil, Jun 2017, Lyon, France. 2017. 〈hal-01478597〉



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