Analysis of the dynamic interaction between SVOCs and airborne particles

Cong Liu, Shanshan Shi, Charles J. Weschler, Bin Zhao, Yinping Zhang

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

A proper quantitative understanding of the dynamic interaction between gas-phase semivolatile organic compounds (SVOCs) and airborne particles is important for human exposure assessment and risk evaluation. Questions regarding how to properly address gas/particle interactions have introduced uncertainty when predicting SVOC concentrations and assessing exposures to these compounds. In this study, we have developed a dimensionless description for the dynamic interaction between SVOCs and organic particles. A better criterion to judge whether the internal resistance (diffusion in and out of aerosols) is negligible compared with the external one (from bulk air to aerosol surfaces) is presented. The analysis is applicable regardless of the phase state of particles (either liquid or amorphous semisolid/solid). It is found that for both porous and nonporous particles, the internal resistance can be reasonably neglected for particles with diameters between 0.01 and 10 μm if the particulate organic matter is in the liquid phase. A lumped description therefore can be applied to determine, with greater accuracy than in previous studies, the timescale required to attain gas/particle equilibrium for such particles. The instantaneous equilibrium assumption is found to be reasonable for relatively volatile species such as pyrene, but not for the less volatile species such as di-(2-ethylhexyl)-phthalate (DEHP). ForDEHPand 2.5 μm diameter particles, the instantaneous gas/particle equilibrium assumption can cause a two orders of magnitude error in the estimation of the gas-phase concentration and a factor of two error in the estimation of the particle-phase concentration. Copyright © American Association for Aerosol Research.
Original languageEnglish
JournalAerosol Science and Technology
Volume47
Issue number2
Pages (from-to)125-136
ISSN0278-6826
DOIs
Publication statusPublished - 2013

Keywords

  • Aerosols
  • Liquids
  • Uncertainty analysis

Fingerprint Dive into the research topics of 'Analysis of the dynamic interaction between SVOCs and airborne particles'. Together they form a unique fingerprint.

Cite this