Application of the octanol-air partition coefficient for describing particle/gas distribution of chlorinated aromatics

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:203612

Harner, T; Bidleman, T ^[1]; Falconer, R ^[2]; Mackay, D ^[3]

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1. Atmospheric Environment Service, Downsview, Ontario (Canada)
2. Youngstown State Univ., OH (United States)
3. Univ. of Toronto, Ontario (Canada)

Partitioning of chlorinated aromatics between the gas and aerosol particulate phases can be explained by adsorption onto active sites on the surface of the aerosol and/or by absorption into a liquid film. In both cases the particle/gas distribution coefficient, K{sub P}, is well correlated with the vapor pressure of the compound. The correlation improves for the adsorption model by including a shape parameter which takes into account the planarity of the molecule. This investigation will consider using the octanol-air partition coefficient, K{sub OA}, as a surrogate for K{sub p}. A method for measuring K{sub OA} is described and results are presented for several PCBs over the temperature range {minus}10 C to + 30 C. The temperature dependence of K{sub P} for PCBs, measured in controlled laboratory experiments, is more closely described by the temperature slope of K{sub OA} than vapor pressure. This supports the hypothesis that absorption into an organic, liquid film is a plausible mechanism for sorption of chlorinated aromatics to urban aerosols. K{sub OA} is also believed to be a valuable descriptor of partitioning of persistent organochlorine chemicals between the atmosphere and lipid-containing phases such as soil and vegetation. Results of particle/gas distributions for PCBs and PCNs (polychlorinated naphthalenes) from field samples collected in Toronto and Chicago are presented and discussed with relation to OA, vapor pressure and planarity.

• OSTI ID: 203612
• Report Number(s): CONF-9511137--; ISBN 1-880611-03-1
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ADSORPTION
AIR POLLUTION
CHLORINATED AROMATIC HYDROCARBONS
CONTROLLED ATMOSPHERES
MATHEMATICAL MODELS
PARTICULATES
PHASE STUDIES
POLYCHLORINATED BIPHENYLS
SORPTIVE PROPERTIES