Breakthrough time of activated-carbon filters used in residential and office buildings- Modelling and comparison with experimental data

While being used for years in industrial applications, gaseous contaminant sorption units suchas activated-carbon filters remain marginal in office and residential buildings. This study deals with models that could help building designers and administrators to design and maintain activated-carbon filters depending on the environmental conditions (pollution load, airflow rate, temperature, humidity) they operate. More precisely, as a necessary first step of the development, the emphasis is put here on demonstrating the relevance of the models by comparing the predicted and measured breakthrough curves of various contaminants (isolated or as a mixture in the air) in dry and isothermal conditions. The results globally show a good agreement between predicted and measured data, while highlighting some interesting trends for future model developments. Beyond the question of model validation, the results also underline great discrepancies in the breakthrough time of the filter from one contaminant to another: the filter breaks within few tens of hours for some species when it breaks after several months for others. Considering the number of contaminant found in indoor settings, this shows that the question of the efficiency of the filter cannot be answered globally, and that the question of how often the filtering medium must be changed is not as simple as one can think.