Hervé Plaisance

Formaldehyde emission behavior of building materials: on-site measurements and modeling approach to predict indoor air pollution.

The purpose of this paper was to investigate formaldehyde emission behavior of building materials from on-site measurements of air phase concentration at material surface used as input data of a box model to estimate the indoor air pollution of a newly built classroom. The relevance of this approach was explored using CFD modeling. In this box model, the contribution of building materials to indoor air pollution was estimated with two parameters: the convective mass transfer coefficient in the material/air boundary layer and the on-site measurements of gas phase concentration at material surfaces. An experimental method based on an emission test chamber was developed to quantify this convective mass transfer coefficient. The on-site measurement of gas phase concentration at material surface was measured by coupling a home-made sampler to SPME. First results had shown an accurate estimation of indoor formaldehyde concentration in this classroom by using a simple box model.

Performance of the Radiello® diffusive sampler for formaldehyde measurement: the influence of exposure conditions and ozone interference

The radial diffusive standard sampler Radiello® filled with Florisil impregnated with 2,4-dinitrophenylhydrazine (DNPH) was evaluated with the goal of survey monitoring the formaldehyde concentration in indoor air for a 4.5 day sampling time. A Radiello® sampler provides measurements with a relative standard deviation of repeatability comprised between 1.5 and 4.0%, a high sampling rate assessed to 98.7 ± 2.8 mL min−1 under standard conditions (temperature: 19.9 ± 0.5 °C and relative humidity: 52.9 ± 3.2%) and a detection limit of 0.5 μg m−3 for a 4.5 day sampling time. The influence of three environmental factors (temperature (T°), relative humidity (RH) and ozone concentration (O3)) on the sampling rate was also evaluated in an exposure chamber following a fractional design of the experiment at two factor levels (low and high). Temperature is found to be the factor leading to the most significant variation of the sampling rate with an effect of +1.8% per °C. From the fractional design of the experiment, a model was set up for expressing the sample rate of Radiello® as a function of significant factors and the uncertainty on the sampling rate was assessed to 11.9% under the domain of tested conditions.

Using the chemical mass balance model to estimate VOC source contributions in newly built timber frame houses: a case study

Basing on the material emission data obtained in a test chamber, chemical mass balance (CMB) was used to assess the source apportionment of volatile organic compound (VOC) concentrations in three newly built timber frame houses. CMB has been proven to be able to discriminate the source contributions for two contrasted environmental conditions (with and without ventilation). The shutdown of the ventilation system caused an increase in the VOC concentrations due to the increased contribution of indoor surface materials like the door material and furniture explaining together over 65% of total VOCs. While the increase in formaldehyde concentration is mainly due to furniture (contribution of 70%), the increase in α-pinene concentration is almost exclusively attributable to the emission of door material (up to 84%). The apportionment of VOC source contributions appears as highly dependent on the position of source materials in the building (surface materials or internal materials) and the ventilation conditions explaining that the concentrations of compounds after the shutdown of ventilation system do not increase in equivalent proportion. Knowledge of indoor sources and its contributions in real conditions may help in the selection of materials and in the improvement of construction operations to reduce the indoor air pollution.