1. Study of SVOCs in Indoor Environment to Support EPA Chemical Safety for Sustainability Program Dr. Xiaoyu Liu U.S. EPA Office of Research and Development National Risk Management Research Laboratory CHAMP 2014, Shenzhen, China July 13, 2014

2. Office of Research and Development National Risk Management Research Laboratory Purpose http://www.epa.gov/planandbudget/annualplan/fy2012.html  Overview EPA Chemical Safety for Sustainability (CSS) Program  Exchange Research Progress  Address Knowledge Gaps and Research Needs  Engage Future Collaboration

3. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory National Research Programs http://www.epa.gov/planandbudget/annualplan/fy2012.html  Six Highly Coordinated, Transdisciplinary Research Programs Air, Climate and Energy (ACE) Chemical Safety for Sustainability (CSS) Homeland Security (HS) Human Health Risk Assessment (HHRA) Safe and Sustainable Water Resource (SSWR) Sustainable and healthy communities (SHC)

4. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory CSS Program  Chemical Safety for Sustainability (CSS Program) Initiated in 2011 Support safe, sustainable design and use of chemicals and materials required to promote human and environmental health. Address the impact of existing chemicals and materials/products across the lifecycle Anticipate the impact of new chemicals and materials/products across the lifecycle Enable consideration and evaluation of complex interactions of chemicals and biological systems to support Agency decisions

5. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory CSS Program  CSS Research Topics Sustainable Chemistry High Throughput Toxicology Rapid Exposure Demonstration and Evaluation for Risk Assessment Emerging Materials Lifecycle and Human Exposure Modeling Ecological Modeling Adverse Outcome Pathway Discovery and Development Virtual Tissues Dashboards

6. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory CSS – SVOCs  Perfluorinated Chemicals (PFCs) and Fluorotelomer Alcohols (FTOHs)  Polychlorinated Biphenyls (PCBs)  Flame Retardants (FR)  Spray Polyurethane Foams (SPF)  iSVOC – SVOC Simulation Tools

7. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory PFCs and FTOHs in Consumer Articles  Source Identification of PFCs and Their Degradation in the Environment Have Been Major Concerns  Source Characterization of PFCs in Two Recent Studies Market monitoring research on consumer articles from the open market over a three-year span to assess the market trends and potential reduction of PFCs upon chemical elimination efforts taken by manufacturers (Liu, et al. Chemosphere, 2014) Determination of FTOH in consumer articles and investigation of their fate in the indoor environment (Liu, et al. Chemosphere, 2014, accepted)

8. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory PCBs in Schools  PCBs in School Caulk containing PCBs used during the 1950s -1970s Fluorescent light ballast capacitors  Source Characterization PCB source emissions and transport evaluated using laboratory chamber testing (Guo, et al., EPA report, 2011) Indoor modeling approaches applied to describe emissions and transport (Guo et al., EPA Report, 2012)  Mitigation Efforts Evaluated the effectiveness of an encapsulation method that reduces the PCBs exposure by creating a barrier over the sources (Guo et al., EPA Report, 2012) Evaluated PCB destruction method based on chemical reactions by reducing PCBs to biphenyl. (Liu et al., EPA Report, 2012)

9. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Flame Retardants in Indoor Environment  Flame retardants are used to meet flammability standards (Hard plastics, Spray foam application, Polyurethane foam, Electronic, Mattress, Textile, Carpet  Organophosphate FRs (OP-FR) Table 1. Target SVOCs- Tris-Organophosphate FRs CAS RNChemical NameSynonyms 115-96-8Ethanol, 2-chloro-, phosphateTCEP 13674-84-52-Propanol, 1-chloro-, 2,2',2''-phosphateTCPP 13674-87-82-Propanol, 1,3-dichloro-, phosphateTDCPP

10. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Flame Retardants in Indoor Environment  Critical parameters for Fate and Transport Study Material/air partition coefficients (K ma ) Solid-phase diffusion coefficients (D s ) Sorption rate constants (e.g. k a, k d ) Liu et al., Indoor Air 2014 Conference, 2014

11. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory SPF Insulation  EPA has a critical need to understand the multi-pollutant emissions from SPF insulation as the basis for improved risk management.  Produce methods, data, and models that characterize emissions from SPF during application, curing, and post-curing across a range of environmental conditions, and link source, exposure to potential adverse health effects  Compounds of interest include: IsocyanatesAmine catalysts PropellantsAldehydes Other VOCs, SVOCsFlame retardants ASTM method developmentMason et al., Indoor air 2014, 2014 Mason et al., SPF symposium, 2015

12. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Experimental Challenges  SVOCs vapor pressure lower than 10 -4 atm Low concentration in the air Long sampling times (at least several hours) Large sampling volume Very small mass gain in the sink material Difficult to measure the mass change Sorption by the wall and sampling lines In general, existing chamber methods for measuring D s & K ma more suitable for VOCs

13. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory SVOC Small Chamber  Small Chamber Design Two chambers connected in series – source and sink chambers Source chamber generated constant emissions of target SVOCs Test materials as small “buttons” in the sink chamber removed at different sorption time Air concentrations monitored at the inlet and outlet of the sink chamber Concentrations in the materials measured by extraction “Pre-Coated” the chamber with OP-FR before placing the test materials

14. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory SVOC Small Chamber Pictures of source chamber and test chamber

15. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory SVOC Small Chamber Pictures of test materials

16. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory SVOC Small Chamber  Improved small chamber testing method can be used to characterize the sink effect of SVOCs on materials The designed lid uses minimal entry points and rods to remove the exposed materials. Multiple sink materials are tested at the same time SVOC concentrations in the materials are determined individually It can detect the SVOCs in the sink material in the microgram range  Data to be used to estimate parameters (D s & K ma ) Use Degree of Sorption Saturation(DSS) model (Deng et al. 2011) to estimate D & K Liu et al. Atmospheric Environment, 2014

17. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Model Challenges  Slow emissions but long-term effects Formation of concentration gradients inside the sources and sinks  Strong sorption by interior surfaces and dust Chamber walls can adsorb as high as 90% of SVOC emissions Source models alone overestimate air concentrations Formation of ”secondary sources” in buildings Significant re-emission from “sinks” after primary sources are removed

18. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Model Challenges  Multiple mass transfer mechanisms material air material material Dust air vs. dust material Liquid applications (multiple driving forces)

19. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Model Challenges

20. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Model Challenges  Problems Incompatibility: Most models cannot co-exist with others Numerical complexity: Many models require solving non-linear equations Unrealistic assumptions: e.g., instantaneous equilibrium between gas-phase and particle-phase SVOCs Omission of source-dust interactions due to direct contact

21. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Simulation Software - iSVOC  Microsoft Windows-based computer program to simulate the emissions, sorption and desorption, and distribution of SVOCs in buildings  Comparable with existing mass transfer models Allows all sub-models to work together Does not rely on proprietary software Improves simulation speed, reduces the computational intensity Easy-to-understand user-interface Allows multiple diffusional sources and sinks to be present in the room provides more flexibility

22. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Simulation Software - iSVOC  Stand-alone application for Windows XP, 7, and 8  Indoor media covered Air (gas-phase) Air (particle phase; allows multiple size bins) Sources (diffusional and non-diffusional) Sinks (diffusional, Lamgmuir, and Freudlich) Settled dust (allows multiple size bins)

23. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Simulation Software - iSVOC  Key input parameters Solid-air partition coefficient (K ma ) Solid-phase diffusion coefficient (D s ) Gas-phase mass transfer coefficient (h m ) Initial SVOC concentrations in indoor media  Output options Concentrations: 12 options; in (μg/m 3 ) or (μg/g) Emission and sorption rates: in (μg/m 2 /h) Guo, Indoor and Built Environment, 2013 a, b

24. July 13, 2014 Office of Research and Development National Risk Management Research Laboratory Acknowledgement  Zhishi Guo  Mark Mason