Improved Method for Measuring and Characterizing Phthalate Emissions from Building Materials and Its Application to Exposure Assessment

Abstract

Phthalate emission from vinyl floorings was measured in specially designed stainless steel chambers. Phthalate concentrations increased and reached steady state after 2 to 5 days for all experiments. By having a high ratio of emission surface to sorption surface, avoiding mass loss of phthalates onto sampling pathways, and improving air mixing inside the chamber, the time to reach steady state was significantly reduced, compared to previous studies (1 to 5 months). An innovative approach was developed to determine y0, the gas-phase concentration of phthalates in equilibrium with the material phase, which is the key parameter controlling phthalate emissions. Target phthalate material-phase concentration (C0) and vapor pressure (Vp) were explicitly measured and found to have great influences on the y0 value. For low phthalate concentrations in materials, a simple partitioning mechanism may linearly relate y0 and C0, but cannot be evoked for high-weight phthalate percentages. In addition, the sorption kinetics and adsorption isotherm of phthalates on stainless steel chamber surfaces were determined experimentally. Independently measured or calculated parameters were used to validate a semivolatile organic compounds (SVOCs) emission model, with excellent agreement between model predictions and the observed chamber concentrations in gas and stainless steel phases. With the knowledge of y0 and emission mechanisms, human exposure to phthalates from tested floorings was assessed; the levels were comparable to previous studies. This work developed a rapid, novel method to measure phthalate emissions; emission measurement results can be connected to exposure assessment and help health professionals estimate screening-level exposures associated with SVOCs and conduct risk-based prioritization for SVOC chemicals of concern.

A simple method to measure the gas‐phase SVOC concentration adjacent to a material surface

“…The observation suggests that y 0 is closely correlated with the material‐phase concentrations and chemical vapor pressure. This conclusion agrees with recent findings by Liang and Xu (), and the fitted values of y 0 are also reasonably consistent with their measurements using the same flooring. Overall, the values of y 0 and K obtained by fitting the model to the sampling data behave in a way that is consistent with the physicochemical properties of the compounds.…”

A SPME-based method for rapidly and accurately measuring the characteristic parameter for DEHP emitted from PVC floorings

“…Sandwichlike chamber 15,20 • Same as CLIMPAQ but using a specially designed chamber with maximized source area and minimized sorption area.…”

“…Several types of ventilated chamber (or cell), including CLIMPAQ, 17,18 FLEC, 18,19 and a sandwichlike chamber, 15,20,21 have been employed to measure y 0 in this way. Several types of ventilated chamber (or cell), including CLIMPAQ, 17,18 FLEC, 18,19 and a sandwichlike chamber, 15,20,21 have been employed to measure y 0 in this way.…”

Emission of Phthalates and Phthalate Alternatives from Vinyl Flooring and Crib Mattress Covers: The Influence of Temperature

“…Using data collected in a specially designed stainless steel chamber, Xu et al 3 showed that the emission rate of di(2-ethylhexyl) phthalate (DEHP) from vinyl flooring can be predicted based on a priori knowledge of y 0 , the gas-phase concentration of DEHP in equilibrium with the material phase, the material to air and air to stainless steel-surface mass-transfer coefficients (h m ), and the stainless steel/air equilibrium relationship. Liang and Xu 30 recently improved the design of the earlier emission chamber and developed a novel, rapid method to measure y 0 for a range of phthalate compounds released from building materials. The mechanisms that govern emissions of phthalates from polymeric materials were also elucidated further by their study.…”