SORPTION OF VOLATILE ORGANIC-COMPOUNDS TO PARTICLES FROM A COMBUSTIONSOURCE AT DIFFERENT TEMPERATURES AND RELATIVE HUMIDITIES

Sorption of polar and non-polar Volatile organic compounds to particle s from a combustion source has been measured at different temperatures and relative humidities in laboratory experiments. The soot particles collected from oil furnaces contained 60% (w/w) iron sulfate and 9% ( w/w) carbon comparable to the chemical composition of aerosol particle s. Sorption experiments were conducted with the unmodified original so ot as well as with a water-extracted subsample. A decrease in the sorp tion with increasing relative humidity was observed for all VOCs on bo th sorbents. Sorption enthalpies calculated from the measured temperat ure dependence of the sorption coefficients suggested stronger sorptio n for polar compared to non-polar compounds of comparable volatility. VOC sorption coefficients normalized to the surface area of the soot w ere greater than have been previously reported for mineral surfaces. A comparison of sorption coefficients with field data for gas-particle partitioning indicated good agreement on the basis of a log K-p,K-s vs log P-L(o) relationship. (C) 1997 Elsevier Science Ltd.