Gas/particle partitioning of organic compounds to environmental tobacco smoke: Partition coefficient measurements by desorption and comparison to urban particulate material

Certain organic compounds in environmental tobacco smoke (ETS) can cause respiratory diseases and lung cancers. The behavior and health effects of EIS will depend upon how each of these compounds is distributed between the gas and the particulate phases. ETS particles were collected on a filter. Semivolatile organic compounds were desorbed from the filter at 20 degrees C using a Row of clean nitrogen at 60% relative humidity. The desorption was followed with time. Volatile, lower molecular weight compounds were released quickly; less volatile compounds were desorbed slowly. A diffusion model was used to estimate gas/particle partition coefficient (K-p) values. The n-alkane and polycyclic aromatic hydrocarbon (PAH) data agreed with prior measurements for ETS by another method. New data for four nitrogen-containing compounds were obtained. At a given pure compound vapor pressure, PAHs were sorbed more strongly than the n-alkanes. The K-p value for nicotine was unusually large, probably due to a significant degree of protonation of the nicotine in the EIS phase. For carbazole, however, which cannot be protonated, K-p was very similar to what would be predicted for a PAH of the same vapor pressure. After normalization for the fraction of organic matter in the particulate phase, the ETS data for PAHs agreed well with data for PAHs sorbing to urban particulate material (UPM). This is consistent with the interpretation that partitioning to both ETS acid UPM is absorptive in nature.