Impact on IAQ of building material emitted pollutants through building leaks: State of the art and sample testing methodology

French authorities have launched an extensive thermal renovation program aiming at retrofitting 4M dwellings over 10 years, with priority given to the most energy consuming ones. Without specific focus on airtightness, retrofitting does not achieve very low airtightness levels, which means numerous leaks in the envelope. Added to the possibility of fungus development at the junction between ancient and new wall, the possibility of airflow conveying pollutants emitted in walls into indoor air is a major concern for public health. Although this concern might apply to all types of construction, this paper will only deal with retrofitted walls, proposing a state of the art and a methodology dealing with the following issue: what is the impact of leaky retrofitted walls on indoor air pollution? 
Literature shows that VOCs are commonly emitted by building construction materials. Still, the proportion of pollutants due to air leakages is scarcely documented. Hayashi et al (2008) discussed however the influence of concealed pollution sources upon IAQ in Japanese houses. 
The use of a test chamber will give some valuable answers to the question raised. The chamber’s purpose is to pressurize a retrofitted wall sample in order to measure the amount of pollutants released by the induced airflow through purposely made building cracks. Temperature, relative humidity and airflow being controlled, TVOC and particles concentrations will be measured in the first place. 
This project will quantify by extrapolation the amount of indoor pollutants due to air leakages. Results will however only partly be generalized, as the continuous pressurization methodology only accounts for mechanical exhaust ventilation.