Measurement of particulate aliphatic and polynuclear aromatic hydrocarbonsin Santiago de Chile: source reconciliation and evaluation of sampling artifacts

Using a novel sampler, particulate organic compounds were collected in Sant iago de Chile from June 9 to August 10, 1997. This sampler consists of a di ffusion denuder to remove gas-phase organics prior to particle collection, a Teflon filter, and a PUF cartridge downstream of the filter. PAHs and n-a lkanes were measured using gas chromatography/mass spectrometry analysis. V olatilization of particles collected on the Teflon filter varied from 15 to 85% for both n-alkanes and PAHs, with strong dependence on molecular weigh t. The relative distribution of n-alkanes and the values of molecular diagn ostic ratios, such as Carbon preference index, indicated a mixed origin wit h strong anthropogenic input. Indeed, CPI values ranged from 0.66 to 1.96 ( for the whole range of n-alkanes). The percent contribution of leaf "wax" n -alkanes (4.55-20.83%) indicated the low contribution of biogenic sources. In addition, the distribution pattern of PAHs was characteristic of anthrop ogenic emissions. The dominant contribution of combustion-related PAHs (CPA Hs), 74-84%, indicated that vehicular emissions was the major source of PAH s. (C) 1999 Elsevier Science Ltd. All rights reserved.