To evaluate the possible role of PAHs and their oxidation products in the toxicity of diesel exhaust (DE) and wood smoke (WS) particulate matter (PM), we have used solid phase extraction (SPE) to fractionate PM methanol extracts. The obtained fractions were analyzed for &gt;120 PAH compounds. The pro-inflammatory effects of both the fractionated extracts and residual PM were characterized through the exposure of bronchial epithelial lung cells (BEAS-2B). Both native DEPM and WSPM caused a concentration-dependent increase in IL-6 and IL-8 release and cytotoxicity. This is consistent with the finding of a rather similar total content of PAHs and PAH-derivatives. Yet, the samples differed in specific components, suggesting that different species contribute to the toxicological response in these two types of particles. The majority of the IL-6 release and cytotoxicity was induced upon exposure to the most polar (methanol) SPE fraction of extracts from both PM samples. In these fractions hydroxy-PAHs, carboxy-PAHs were observed along with nitro-amino-PAHs in DEPM. However, the biological effects induced by the polar fractions could not be attributed only to the occurrence of PAH-derivatives. Moreover, in contrast to the native PM none of the tested fractions induced IL-8, implying that central constituents or important combinatory effects might have been lost during the fractionation process. Thus a new comprehensive extraction approach was developed addressing broader range of extractable organics (i.e., beyond those extracted by methanol).  Two high pressure extraction strategies were employed, differing in the polarity sequence of extraction solvents: 1) a series of organic solvents (at 100 °C) complemented by extraction with water (25 °C); 2) 25 °C water followed by steps with 50, 100, and 150 °C and then completed with nonpolar organic solvent. The PM fractions were characterized based on the organic carbon content, distribution of PAHs and their oxidation products as well as other major classes of compounds including alkanes, carboxylic acids, aldehydes and  high molecular weight species using a broad range of analytical methods developed in our laboratory including also thermal desorption-pyrolysis-gas chromatography with mass spectrometry. The comprehensive chemical characterization results will be evaluated with regard to the toxicological response of individual fractions.<br/>

Main contributors to the diesel exhaust and wood smoke particles toxicity. Do we know them?

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.