Innovative tools and modeling methodology for impact prediction and assessment of the contribution of materials on indoor air quality

Abstract

Background:The combination of more and more airtight buildings and the emission of formaldehyde and other volatile organic compounds (VOCs) by building, decoration and furniture materials lead to lower indoor air quality. Hence, it is an important challenge for public health but also for the preservation of cultural heritage, as for example, artworks in museum showcases and other cultural objects. Indeed, some VOCs such as organic acids or carbonyl compounds may play a role in the degradation of some metallic objects or historic papers. Thus, simple and cost effective sampling tools are required to meet the recent and growing demand of on-site diagnostic of indoor air quality, including emission source identification and their ranking. Results:In this aim, we developed new tools based on passive sampling (Solid-Phase Micro Extraction, SPME) to measure carbonyls compounds (including formaldehyde) and other VOCs and both in indoor air and at the material/ air interface. On one hand, the coupling of SPME with a specially designed emission cell allows the screening and the quantification of the VOCs emitted by building, decoration or furniture materials. On the other hand, indoor air is simply analysed using new vacuum vial sampling combined with VOCs pre-concentration by SPME. These alternative sampling methods are energy free, compact, silent and easy to implement for on-site measurements. They show satisfactory analytical performance as detection limits range from 0.05 to 0.1 µg m −3 with an average Relative Standard Deviation (RSD) of 18 %. They already have been applied to monitoring of indoor air quality and building material emissions for a 6 months period. The data obtained were in agreement with the prediction of a physical monozonal model which considers building materials both as VOC sources and sinks and air exchange rate in one single room ("box model"). Conclusion:Results are promising, even if more data are required to complete validation, and the model could be envisaged as a predictive tool for indoor air quality. This new integrated approach involving measurements and modeling could be easily transposed to historic environments and to the preservation of cultural heritage.

New sampling device for on-site measurement of SVOC gas-phase concentration at the emitting material surface

“…The compounds are emitted by the material until reaching equilibrium between the material and chamber air. From first Fick law under steady state conditions [35], the concentration in the chamber can be assimilated to the concentration y 0 , which is measured by introducing a solid-phase microextraction (SPME) fiber into the chamber via a septum (this approach is similar to that we developed for VOCs, which is described in the following [36]). However, these different methods of emission measurement are performed in the laboratory and thus are not representative of real indoor environments: they neither consider the conditions of implementation of materials nor the possible effects of assemblies on emission (e.g., for furniture, the layering of cushioning foam, interlining materials, and coatings).…”

“…Therefore, the development of an on-site method to determine the gas-phase SVOCs concentration at the material surface is relevant and constitutes the main objective of this work. The considered device is inspired by a system previously developed in our laboratory for on-site measurement of y 0 for VOCs [36]. It consists of coupling a home-made glass cell (DOSEC) with SPME.…”

Under glass weathering of hemp fibers reinforced polypropylene biocomposites: Impact of Volatile Organic Compounds emissions on indoor air quality

“…This methodology allows determining the VOCs concentrations at the material/air interface (also called surface concentration) which is related to the emission rate through the First Fick law of diffusion [38,39].…”

“…Hence, this sampling procedure is not relevant to provide quantitative data related to surface emission. The sampling methodology used for this work and previously developed in our laboratory, is based on a home-made emission cell coupled with SPME [38,39]. This simple and non-destructive passive sampling method allows determining the VOCs concentration at the material/air interface which is related to the emission rate by the first Fick's law of diffusion under steady state conditions [39].…”

Potential of static sampling using solid-phase microextraction for the assessment of formaldehyde sorption on building materials

“…Another alternative is the using of Solid Phase Micro-Extraction (SPME) sampling performed in an airtight emission cell. Recent developments regarding the on-fiber derivatization allowed to expand the potential of SPME to measure gaseous formaldehyde at ppb level and to combine it with emission cell to assess the gaseous concentration at the material surface (Desauziers et al, 2015). Fast changes in the concentration can be assessed by successive short samplings with solid-phase microextraction fibers.…”