Validation of a passive flux sampler for on-site measurement of formaldehyde emission rates from building and furnishing materials

Abstract

A diffusive sampling device was developed for screening indoor sources of formaldehyde and determining the emission rates of these sources on-site. It consists of a glass Petri dish containing a quartz filter coated with 2,4-dinitrophenylhydrazine (DNPH) which is placed on the tested material for sampling. Formaldehyde emitted from the material diffuses through the air column inside the sampler and is collected onto the DNPH filter. The formaldehyde emission rate is determined from the mass collected by the sampler. The dependence of the sampled formaldehyde amount on the diffusion length inside the sampler was examined and led us to select a length of 20 mm for which the diffusion in the air layer controls the mass transfer from the material to the sampling surface (filter). A linear relationship with a high correlation (r 2 ¼ 0.97) was obtained between the mass collected by the passive flux sampler and the emission rates measured by a standard chamber method, analysing a large series of indoor materials with the two methods in parallel. Neither the sampling time (ranging from 4 to 8 h) nor the temperature (from 23 to 35 C) was observed to influence the sampler performance. Furthermore, the detection limit attained 1.2 mg m À2 h À1 for a 6h-sampling time and a satisfying precision of replicate measurements (relative standard deviation of 7.8% on average) is adequate for monitoring the emission rates of primary sources contributing to formaldehyde indoor concentrations.

Field investigation on the removal of formaldehyde in indoor air

“…More details on this method were given in Ref. [1]. The flow sampling rate was maintained constant to 1 L min À1 as recommended by the ISO 16000-3 standard [12] and checked before and after each experiment with a flow meter (DryCal DC-Lite) certified against the national reference standard of Laboratoire National d'Essais (LNE).…”

“…Assessing the potential impacts of air pollutant exposure on human heath requires an understanding of not only the range of indoor levels but also the contributions of sources and indoor sinks on the concentrations under typical household conditions. Different types of miniature emission chambers, like the passive flux samplers [1,2] or standard FLEC Ò emission cell coupled with an active sampling method [3] or with solid-phase microextraction [4] are now available for in situ measurement of the flux of organic compounds emitted from various kinds of indoor materials. In contrast, few data exist on the removal of organic compounds from indoor sinks.…”

Static SPME sampling of VOCs emitted from indoor building materials: prediction of calibration curves of single compounds for two different emission cells

“…Initial conditions:t =0, C r,z =C o, C 1,z =0, q z =0 for the equilibrium model, C int,z =0 q rs,z =0 for the solid diffusion model with C o the initial VOC concentration in the gas sampler.Partial differential equations (Eqs. 5bis, 10bis, 11,12,14) are transformed by substituting finite-difference approximations. The alternating-direction implicit scheme provides a mean for solving parabolic equations in two spatial dimensions using tridiagonal matrices [27].…”

“…These protocols, covered by ISO standards [7,8], are adapted to laboratory testing for material labeling but are not able to evaluate the material behavior in field in the aim of determining their impact in indoor air quality. For this purpose, static sampling methods [9][10][11] are recently investigated for simpler and faster on-site sampling. One of these methods is developed in our laboratory [12,13].…”

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

“…These protocols, covered by ISO standards [9,10], were suitable for laboratory testing for material labeling but were not able to evaluate the material behavior in real indoor environments in the aim of determining their impact on indoor air quality. For this purpose, static sampling methods [11][12][13][14] have been recently investigated to obtain simpler and faster on-site sampling. One of these methods consisted of coupling a standard FLEC ® emission cell in static mode with solid-phase microextraction (SPME) for rapid sampling and simple thermal desorption, directly performed in a GC injector and allowed a multi-pollutant analysis [15,16].…”