Applications of group contribution methods to the partitioning of semi-volatile organic compounds on atmospheric particulate matter
- Univ. of North Carolina, Chapel Hill, NC (United States)
The gas-particle partitioning of a semi-volatile organic compound (SOC) to atmospheric aerosols with organic coating is strongly influenced by temperature (vapor pressure), relative humidity (RH), the chemical composition of the particulate matter, and the amount of organic material in the particulate matter. Experimental partitioning coefficients (K{sub p}) of SOCs were measured using the outdoor Teflon film chambers and compared to theoretical calculated K{sub p} values as determined from SOC vapor pressures and associated activity coefficients. A thermodynamic model based on group contribution methods was used to estimate the activity coefficients of SOCs in the organic liquid layer of different types of aerosols. Because the true K{sub p} of an SOC in a given medium includes the activity coefficient term, the linearity between log K{sub p} and log P{degrees}{sub (L)} can be obtained by correcting measured K{sub p} values by the activity coefficient of given SOC at a given temperature and humidity. In this work the partitioning of different types of SOCs on atmospheric particles consisting of liquid-like organic component, such as wood smoke, diesel soot, and secondary aerosol, was studied as a function of temperature and relative humidity in outdoor experimental chambers.
- OSTI ID:
- 617805
- Report Number(s):
- CONF-9704195--
- Country of Publication:
- United States
- Language:
- English
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