Alternative approaches for modeling gas-particle partitioning of semivolatile organic chemicals: model development and comparison.
We present a novel model of gas-particle partitioning based on polyparameter linear free energy relationships (ppLFERs) that is capable of representing a broad range of aerosol properties. We apply the model to semivolatile organic chemicals including PCBs, DDT, and polar pesticides, and compare it to a widely adopted model based on the octanol-air partition coefficient (K(OA)). For nonpolar chemicals and cases where sorption to aerosols is dominated by absorption into organic matter, the two models are highly correlated and both are appropriate. Significant differences between the models are found for (a) polar chemicals and (b) aerosols with low organic matter content. The explicit description of polar interactions in the ppLFER approach implies stronger interactions between chemicals and aerosols than the K(OA)-based model, which describes polar interactions only implicitly and to a limited extent. Practical application of the ppLFER-based model to a wide range of chemicals is currently limited by data gaps in measured Abraham solvation parameters and uncertainties in estimation methods.
Götz
Christian W
CW
Safety and Environmental Technology Group, Institute for Chemical and Bioengineering, Swiss Federal Institute of Technology, ETH Zurich, Switzerland.
Scheringer
Martin
M
MacLeod
Matthew
M
Roth
Christine M
CM
Hungerbühler
Konrad
K
D000327:Adsorption; D000336:Aerosols / Q000737:chemistry*; D000393:Air Pollutants / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D006813:Humidity; D008956:Models, Chemical; D052638:Particulate Matter; D010575:Pesticides / Q000737:chemistry; D011078:Polychlorinated Biphenyls / Q000737:chemistry; D014835:Volatilization
D000336:Aerosols; D000393:Air Pollutants; D005740:Gases; D052638:Particulate Matter; D010575:Pesticides; D011078:Polychlorinated Biphenyls