Standard Formaldehyde Source for Chamber Testing of Material Emissions: Model Development, Experimental Evaluation, and Impacts of Environmental Factors

Abstract

Formaldehyde, which is recognized as a harmful indoor air pollutant for human health, is emitted mainly from urea-formaldehyde resin in wood products. Chamber tests are used to evaluate formaldehyde emission rates from these products. However, there is no available formaldehyde standard reference emission source to assess the performance of chamber testing systems. In this work, a LIFE (liquid-inner tube diffusion-film-emission) formaldehyde reference is described. The formaldehyde source consists of a polytetrafluoroethene (PTFE) tube that holds a formaldehyde-water solution with a concentration of 16 g formaldehyde per 100 mL water, with a thin polydimethylsiloxane (PDMS) film cover. Formaldehyde emission parameters for the PDMS film (diffusion coefficient and partition coefficient) were determined experimentally, thereby enabling the prediction of the formaldehyde emissions from the source for use as a reference value in a chamber. Chamber tests were conducted in a 51 L stainless steel ventilated chamber. The impacts of temperature and relative humidity on the emissions were investigated. Results show the LIFE's chamber test results match those predicted by a mass transfer model. As a result, this formaldehyde source may be used to generate a reference concentration in product emission testing chambers, thereby providing a powerful tool to evaluate the performance of the chamber testing systems.

Influence of Precision of Emission Characteristic Parameters on Model Prediction Error of VOCs/Formaldehyde from Dry Building Material

“…Chemical reactions for active VOCs and formaldehyde in building materials and the air sometimes occur, e.g., in the presence of ozone. However, model predictions provide ideal evaluations of VOC/formaldehyde concentrations in the indoor environment, and can agree well with the experimental data from well-performed environmental chamber tests [8], [31], [32].…”

Assessment of steady state diffusion of volatile organic compounds in unsaturated building materials based on fractal diffusion model

“…Additionally, some studies have been devoted to the elucidation of the effect of humidity on the diffusion of VOCs in building materials [7]. Few research works focus on the macro-scale relative humidity dependence of water/ gas diffusion of unsaturated building materials from the theoretical point of view [49].…”

“…However, questions regarding the performance of environmental chamber testing systems and the errors associated with the measurements of VOCs from building materials have been raised: results measured from environmental chamber testing systems present considerably scattered distribution [9], as shown in Table 1. This may be attributed to two factors [7]: 1) the reliable diffusion values of building materials are still unknown until now, it is thus lack of critical value for comparing the results among various laboratory measurements; and 2) different building materials/VOCs/test methods/conditions used in various laboratories may be one of sources of scattered data [10e18]. In particular, some studies considered that either chamber testing approaches or other cup methods may be inappropriate for some porous materials [14,17].…”

Machine learning and statistical models for predicting indoor air quality

“…Indoor air quality is commonly predicted using mechanistic models based on an understanding of the underlying mechanisms governing the fate and transport of indoor air pollutants, including, for example, diffusion of compounds from source materials, convective mass transfer of compounds in air, and sorption of compounds into or onto sink materials. Mechanistic models have been developed to predict the concentrations of volatile organic compounds (VOCs), [1][2][3][4] semi-volatile organic compounds (SVOCs), [5][6][7] aldehydes, [8][9][10] inorganic compounds including radon, [11][12][13][14] and particulate matter (PM) [15][16][17][18][19] in indoor environments. Mechanistic models require detailed inputs on both indoor sources and sink materials for the target pollutants, building envelope and ventilation conditions, and outdoor concentrations of the target pollutants.…”