Future Trends of Indoor SVOC Partitioning under Climate Change: Temperature-Dependent Partition Coefficients

Abstract

We used ten representative semivolatile organic compounds (SVOCs) to investigate how changes in temperature and particle concentration affect future concentrations and partitioning of SVOCs in the gas phase, particulate phase, and on surfaces in the indoor environment. Using quantum mechanical methods and quantitative structure–activity-relationship (QSAR) tools, accurate temperature-dependent octanol/air partition coefficients (KOA) and vapor pressures (PL) of the subcooled liquid were calculated. Under the pessimistic greenhouse gas emissions scenario SSP5–8.5 as projected by the Intergovernmental Panel on Climate Change (IPCC), an annual shift in the SVOC equilibrium concentration between gas phase, particle phase, and surface by up to 30% is expected until 2100. The SSP5–8.5 scenario leads to higher SVOC emission rates and changes in the organic film thickness on surfaces. However, since primarily annual averages are considered, these temperature-related changes are small. Nevertheless, a model calculation for the emission rate of DINCH, taking into account extreme daily indoor temperatures, was performed. Since many developments up to 2100 can only be estimated, simplifying assumptions were made for emission rates, film thickness, and other parameters.