The dynamic partitioning of airborne phthalates in indoor environment: effects of ventilation

Abstract

Low energy consumption buildings with strong air tightness such as passive buildings are the development trend in the world. However, ventilation directly affects the emission and dynamic transport of indoor phthalates. A transient partition model considering the dynamic behavior of size-resolved particle was utilized to investigate the influence of ventilation on the airborne Di-2-ethylhexyl phthalate (DEHP). The air exchange rate (a) was set to 0.15 h-1, 0.3 h-1, 0.6 h-1, 2h-1 for the different conditions. The predicted gas-phase concentration of DEHP in the initial 70 days is unaffected for different a and constant hms, whereas it raises until the a increases to 2 h-1. The equilibrium gas-phase concentration decreases from 0.257 to 0.203 μg/m3. Meanwhile, the higher a also reduced the particle-phase concentration of DEHP. Furthermore, the changes of airborne DEHP were analyzed by considering the impact of a on hms caused by ventilation. The results indicates that more ventilation leads to higher gas-phase concentration for the whole stage. The gas-phase concentration at equilibrium increases from 0.237 to 0.440 μg/m3. The total airborne (gas-phase + particle-phase) concentration decreases with the higher ventitation rate, which indicates that the ventitation has a positive effect on indoor airborne DEHP.