Prediction model for SVOCs transport in the air and interactions with airborne particles

- An unsteady mathematical model for SVOCs transport in the air is proposed.
- The concentration variations of both particles and DEHP in a chamber are obtained.
- Smaller particles lead to a higher concentration of particle-phase DEHP.
- The concentration of DEHP in a larger chamber needs a longer time to reach steady-state.
- The air flow rate in the studied chamber is recommended between 100 and 1000 mL/min.

Semi-volatile organic compounds (SVOCs), harmful contaminants to human health, have a strong sorption tendency to the airborne particles, which affects the SVOCs transport process in the air and increases the total SVOC concentration. In this paper, a mathematical model for describing the transport mechanism of SVOCs in the air and interactions with airborne particle was proposed. After validated by Benning et al. (2013)'s experimental results, the numerical results by the proposed model show that the particle-phase concentration of DEHP at the chamber outlet reduces rapidly when the air flow rate is higher than 400 mL/min, the particles will go on sorbing/desorbing DEHP in the sampling trains downstream the chamber, smaller particles lead to a higher concentration of particle-phase DEHP in the chamber, and a larger chamber leads to a higher steady-state concentration but a slower process that the DEHP concentration reaches steady-state. Besides, there is a certain range for air flow rate in different chambers, e.g. 100-1000 mL/min in this study, to ensure the sorption of DEHP onto particles reaching the gas-/particle-phase equilibrium and reduce the errors induced by the deposition of particles.