Outline of ULg chemical sensors applications for IAQ evaluation

The arrival of the European and National laws* concerning the official labelling of building materials (CE marking) and the respect of concentration values for some compounds regulations in public buildings as for instance schools, the emergence of the Environmental Assessments of buildings (Breeam, HQE,…) beside the energy performance, as well as the awareness increase of the impact of indoor air quality on the wellness and health (ie ENVIE and Healthvent projects [1]) lead inevitably to the development of new sensing technologies related to the IAQ evaluation.
Among the numerous existing measurement devices, electrochemical cells, NDIR and PID ones are the most encountered sensors on the market. The major uses are real time monitoring (CO2) and “friendly” handheld devices.
Other applications are also studied in several research labs. Few years ago, the ULg research team investigated the interest of MOS chemical sensors arrays for IAQ evaluation. This presentation aims to review some of the results of those projects.
A first is the fast and simple diagnosis of moulds on building materials. The identification of contaminated materials among uncontaminated ones was successful [2-4]. However, the low concentration of the MVOC markers compounds (below 10 µg/m³) and the complexity of the background (material emissions, and VOC content of the indoor air) curbed the use of MOS sensors. Specific preconcentrations have to be developed to improve the diagnosis. Nowadays, with the emergence of new sensing materials and new measurement principles (eg IMS-ion mobility spectrometry [5]), perspectives are again opened. Another project (HEMICPD, Belgian project “Horizontal evaluation method for the implementation of the Construction Products Directive”-Emissions to indoor air [6]) concerned the marking of building materials and one of the tasks was to test the sensors array principle to monitor the compounds emanation from different building material, during 28 days, in emission test chambers. Another goal was to investigate a classification of the materials including their odour level. The results on the use of sensors to evaluate the efficiency of “masking” products pulverised in wallpapers and to manage their use are also explained.