Grantee Research Project Results
2017 Progress Report: Rapid Methods to Estimate Exposure to SVOCs in Indoor Environments
EPA Grant Number: R835606Title: Rapid Methods to Estimate Exposure to SVOCs in Indoor Environments
Investigators: Little, John C , Marr, Linsey C.
Institution: Virginia Tech
EPA Project Officer: Aja, Hayley
Project Period: July 1, 2014 through June 30, 2017 (Extended to June 30, 2018)
Project Period Covered by this Report: July 1, 2016 through June 30,2017
Project Amount: $900,000
RFA: New Methods in 21st Century Exposure Science (2013) RFA Text | Recipients Lists
Research Category: Chemical Safety for Sustainability
Objective:
1. Develop novel method to measure the gas-phase SVOC concentration (y0) adjacent to the material surface in a consumer product;
2. Measure occurrence of SVOCs in consumer products (C0) and use resulting data to establish the nature of equilibrium relationship between C0 and y0;
3. Conduct single-source experiments to characterize emissions of various SVOCs from the representative sources;
4. Develop novel method to determine surface/air partition coefficients for selected SVOCs and six interior surfaces including airborne particles and dust;
5. Validate the single-source model using results from the chamber experiments for representative sources and the single-phase model using data collected from the literature; and
6. Evaluate assumptions on which the rapid single-source and single-phase methods are based and characterize the uncertainty inherent in model predictions, especially for the low volatility SVOCs.
Progress Summary:
Substantial progress has been made towards meeting all project goals, with the results reported below and in the listed publications and presentations.
• Development of a simple and rapid method to measure the gas-phase SVOC concentration immediately adjacent to the material surface (y0) in a consumer product (Figure 1) (Wu, Xie et al. 2015).
Figure 1. Left: Schematic representation of the diffusive sampler and diffusion model. Right: Measured DEHP in the tube as a function of time and best-fit model curves for green PVC flooring. The black line overlaps with the red line. (Wu, Xie et al. 2015)
• Further improvement of this measurement method using solid-phase microextraction (SPME) (Figure 2) (Cao, Zhang et al. 2016).
Figure 2. a) Schematic representation of the experimental setup and b) photographs of the setup. (Cao, Zhang et al. 2016)
• Measurements of the concentration of phthalates in consumer products (C0) and evaluation of the mass transfer to clothing and human skin (Xie, Wu et al. 2015).
• Application of our proposed emission model to emission profiles obtained with a reference method for emission characterization in small chamber tests (Figure 3) (Wu, Cox et al. 2016).
Figure 3. Schematic representation of the chamber test setup evaluated in an inter-laboratory study. (Wu, Cox et al. 2016)
• Development of a novel method to measure the vapor pressure of SVOCs (Figure 4) (Wu, Eichler et al. 2016).
Figure 4. Schematic representation of the PS tube setup. (Wu, Eichler et al. 2016)
• Development of a novel method to characterize particle-enhanced mass transfer of SVOCs (Wu, Chen et al. In preparation).
• Development of a novel method to measure the surface/air partitioning coefficient Ks (Figure 5) (Wu, Eichler et al. 2017).
Figure 5: Measured DEHP mass accumulated on the impervious surface as function of time and best-fit model curves for (to the left) aluminum, stainless steel #1, stainless steel #2, and steel, and (to the right) ground glass, polished glass, and acrylic. (Wu, Eichler et al. 2017)
• Extensive literature research and, based on the findings and our own emission model, the suggestion of a mechanistic, screening-level framework for exposure assessment (Eichler, Wu et al. In preparation).
Future Activities:
The investigation of the correlation between C0 and y0 as part of Objective 2 is one major focus. Additionally, the work on the partitioning coefficients as described in Objective 4 will be extended by the measurement of Kdermal, the partitioning coefficient between human skin and air. Further work will be done regarding Objectives 5 and 6.
References:
Cao, J., X. Zhang, J. C. Little and Y. Zhang (2016). "A SPME-based method for rapidly and accurately measuring the characteristic parameter for DEHP emitted from PVC floorings." Indoor Air 27: 417-426.
Eichler, C. M. A., Y. Wu, L. C. Marr and J. C. Little (In preparation). "A Mechanistic Framework for Improved Screening-level Exposure Assessment."
Wu, Y., S. Chen, C. Liu, M. Xie, E. Vejerano, S. S. Cox, L. C. Marr and J. C. Little (In preparation). "A reference method to determine particle-enhanced mass transfer of SVOCs."
Wu, Y., S. S. Cox, Y. Xu, Y. Liang, D. Won, X. Liu, P. A. Clausen, L. Rosell, J. L. Benning, Y. Zhang and J. C. Little (2016). "A reference method for measuring emissions of SVOCs in small chambers." Building and Environment 95: 126-132.
Wu, Y., C. M. A. Eichler, S. Chen and J. C. Little (2016). "Simple Method To Measure the Vapor Pressure of Phthalates and Their Alternatives." Environmental Science & Technology 50: 10082-10088.
Wu, Y., C. M. A. Eichler, W. Leng, S. S. Cox, L. C. Marr and J. C. Little (2017). "Adsorption of Phthalates on Impervious Indoor Surfaces." Environmental Science & Technology 51(5): 2907-2913.
Wu, Y., M. Xie, S. S. Cox, L. C. Marr and J. C. Little (2015). "A simple method to measure the gas-phase SVOC concentration adjacent to a material surface." Indoor Air 26(6): 903-912.
Xie, M., Y. Wu, J. C. Little and L. C. Marr (2015). "Phthalates and alternative plasticizers and potential for contact exposure from children’s backpacks and toys." Journal of Exposure Science and Environmental Epidemiology 26: 119-124.
Journal Articles on this Report : 7 Displayed | Download in RIS Format
| Other project views: | All 35 publications | 11 publications in selected types | All 11 journal articles |
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Cao J, Zhang X, Little JC, Zhang Y. A SPME-based method for rapidly and accurately measuring the characteristic parameter for DEHP emitted from PVC floorings. Indoor Air 2017;27(2):417-426. |
R835606 (2016) R835606 (2017) |
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Wu Y, Cox SS, Xu Y, Liang Y, Won D, Liu X, Clausen PA, Rosell L, Benning JL, Zhang Y, Little JC. A reference method for measuring emissions of SVOCs in small chambers. Building and Environment 2016;95:126-132. |
R835606 (2015) R835606 (2016) R835606 (2017) |
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Wu Y, Liu Z, Herrera-Alonso JM, Marand E, Little JC. A new method to predict the effective diffusion coefficient of gases and vapors in polyurethane/clay nanocomposite membranes. Journal of Membrane Science 2016;510:201-208. |
R835606 (2017) |
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Wu Y, Eichler CM, Chen S, Little JC. Simple method to measure the vapor pressure of phthalates and their alternatives. Environmental Science & Technology 2016;50(18):10082-10088. |
R835606 (2016) R835606 (2017) |
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Wu Y, Eichler CM, Leng W, Cox SS, Marr LC, Little JC. Adsorption of phthalates on impervious indoor surfaces. Environmental Science & Technology 2017;51(5):2907-2913. |
R835606 (2017) |
Exit Exit Exit |
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Xie M, Wu Y, Little JC, Marr LC. Phthalates and alternative plasticizers and potential for contact exposure from children’s backpacks and toys. Journal of Exposure Science and Environmental Epidemiology 2016;26(1):119-124. |
R835606 (2015) R835606 (2016) R835606 (2017) |
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Wu Y, Xie M, Cox SS, Marr LC, Little JC. A simple method to measure the gas-phase SVOC concentration adjacent to a material surface. Indoor Air 2016;26(6):903-912. |
R835606 (2016) R835606 (2017) |
Exit Exit Exit |
Supplemental Keywords:
Risk assessment, pollution prevention, toxics, environmental chemistry, SVOCs, indoor airProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.