Citation:

Liang, Y., X. Liu, AND M. Allen. Measurements of Parameters Controlling the Emissions of Organophosphate Flame Retardants in Indoor Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 52(10):5821-5829, (2018).

Impact/Purpose:

SVOCs can be found across a range of chemical classes and chemical functional uses including phthalate esters, flame retardants, pesticides, and preservatives. The fate and transport of SVOCs and human exposure to these pollutants have emerged as a high priority research. The specific objectives are to: 1) develop an improved material-air-material (M-A-M) configured microchamber that is self-sealed to rapidly measure the value of y0 for polyisocyanurate rigid (PIR) foam containing OPFRs, 2) apply the diffusive tube sampling test method and the dual small chamber sorption test method to determine y0 for the PIR foam and compare with the y0 values obtained from the microchamber emission test, 3) propose a simple and rapid method to estimate y0 values for source materials of SVOCs, and 4) compare the advantages and disadvantages of different SVOC testing methods for future research.

Description:

Emission of semi-volatile organic compounds (SVOCs) from source materials usually occurs very slowly in indoor environments due to their low volatility. When the SVOC emission process is controlled by the external mass transfer, the gas-phase concentration in equilibrium with the material (y0) is used as a key parameter to simplify the source models that are based on solid-phase diffusion. A material-air-material configured microchamber method was developed to rapidly measure y0 for a polyisocyanurate rigid foam containing organophosphate flame retardants (OPRFs). The test was conducted in two 44 mL microchambers for target OPFRs including tris(2-chloroethyl) phosphate (CASRN: 115-96-8), tris(1-chloro-2-propyl) phosphate (CASRN: 13764-84-5) and tris(1,3-dichloro-2-propyl) phosphate (CASRN: 13674-87-8). In addition to the microchamber emission test, two other types of tests were conducted to determine y0 for the same foam material: OPFR diffusive tube sampling tests from the OPFR source foam using stainless-steel thermal desorption tubes and sorption tests of OPFR on an OPFR-free foam in a 53-L small chamber. The values of y0 obtained with different methods were compared. Based on the y0 measurements, a linear relationship between the ratio of y0 to vapor pressure and material-phase mass fractions of phthalates and OPFRs has been found for SVOCs with mass fractions <15%.

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