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Understanding Semi-volatile Organic Compounds (SVOCs) in Indoor Dust
Citation:
Liu, X. Understanding Semi-volatile Organic Compounds (SVOCs) in Indoor Dust. Indoor and Built Environment. SAGE Publications, THOUSAND OAKS, CA, , 0, (2022). https://doi.org/10.1177/1420326X211070859
Impact/Purpose:
EPA’s Chemical Safety for Sustainability (CSS) national research program is to enhance scientific approaches for understanding current and emerging chemicals, and how this is essential for effective environmental decision making under the Toxic Substances Control Act (TSCA) amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act. Understanding the transport mechanisms of semivolatile organic compounds (SVOCs) between sources, air, airborne particles, house dust, and interior surfaces is critial to predict the SVOC exposure in indoor environments. This manuscript summarizes the literature data of SVOCs, such as polychlorinated biphenyls (PCBs), flame retardants, and per- and polyfluoroalkyl substances (PFASs), in indoor dust, and their mass transfer pathways via absorption, desorption, dust/air and dust/material partitioning, particle formation through abrasion, and migration via direct contact between SVOCs sources and dust. Information and data regarding fate and transport and exposure of chemicals in indoor dust will support EPA programs and regions to make risk-based decisions of priority chemicals with a better understanding of their potential risks to human health and the environment.
Description:
Interaction of indoor dust and chemicals is an important source of human exposure. Per- and polyfluoroalkyl substances (PFASs), inadvertently generated polychlorinated biphenyls (iPCBs), and organophosphorus flame retardants (OPFRs) have been detected in various consumer products and building materials, and globally found in indoor dust in concentrations ranging from several ng/g to thousands of µg/g. They are semivolatile organic compounds (SVOCs) with saturation vapour pressures between 10-2 and 10-8 kPa at 25°C. The mass transfer mechanism responsible for SVOC transport from sources to indoor dust includes absorption, desorption, dust/air and dust/material partitioning, particle formation through abrasion, and migration via direct contact between SVOCs sources and dust. The key parameters controlling these mass transfer processes are vapor pressure, octanol-air partitioning coefficient (KOA), dust-air equilibrium partition coefficient (Kda), dust diffusion coefficients (Dd), and dust-source material partition coefficient (Kds). Environmental chambers are the most commonly used methodology for experimental investigation of mass transfer mechanisms between chemicals and dust. Due to technical challenges, literature data of Kda, Dd, and Kds for PFASs, iPCBs, and OPFRs are rare but they are of great interest to researchers and regulators. Information and data regarding fate and transport and exposure of chemicals in indoor dust will support scientific and public health institutions to understand the dust mode of exposure of SVOCs and inform public health protection measures.
