Kinetic analysis of TCPP emission from fireproofed upholstered furniture under realistic indoor conditions

Abstract

Better understanding the characteristics and mechanisms governing the indoor emissions of organophosphorus flame-retardants is important to more accurately estimate the human exposure to these compounds and develop risk management strategies that protect human health. This study provides an analysis of short- and long-term trends in Tris(chloropropyl)phosphate (TCPP) emissions from furniture. It is based on the monitoring over a period of almost one year of TCPP concentrations in indoor air and at the surface of a source material (upholstered furniture made of polyurethane (PU) foam containing TCPP) in two rooms for office use. The emission rate was estimated at 8 µg.m^-2.h^-1 in average with no decline trend observed after about one year's emission. The released mass of TCPP over one year represented about 0.2 % of the initial content of TCPP in the material (2 % w/w). The source material/air partition coefficient (K_ma) and its dependence on temperature appear to be the key parameters which control the emission rate. K_ma was estimated at 8 × 10⁷ for a temperature of 23 °C. The temperature dependence of K_ma was addressed using the Clausius–Clapeyron relationship and the enthalpy of partitioning between the source material and air, ΔH_ma (previously estimated at 91 kJ mol⁻¹). This study led to the development of a model providing predictions on the long-term trend in TCPP emission from the source material. The simulations showed that the emission should persist over extended periods (several years) with the same intensity level. This characteristic increases the risks associated with inhalation exposure to TCPP.