Characterizing priority polycyclic aromatic hydrocarbons (PAH) in particulate matter from diesel and palm oil-based biodiesel B15 combustion

A set of 16 priority polycyclic aromatic hydrocarbons (PAH) associated with particulate matter (PM), emitted by a diesel engine fueled with petroleum diesel and a 15%-vol. palm oil methyl ester blend with diesel (B15), were determined. PM was filtered from a sample of the exhaust gas with the engine running at a steady speed and under no load. PAH were extracted from the filters using the Soxhlet technique, with dichloromethane as solvent. The extracts were then analyzed by gas chromatography using a flame ionization detector (FID). No significant difference was found between PM mass collected when fueled with diesel and B15. Ten of the 16 PAH concentrations were not reduced by adding biodiesel: Benz(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-c,d)pyrene, naphthalene and phenanthrene. The acenaphthene, acenaphthylene and anthracene concentrations were 45%–80% higher when using diesel, whereas those for benzo(k)fluoranthene, benzo(g,h,i)perylene and pyrene were 30%–72% higher when using the B15 blend. Even though the 16 priority-PAH cumulative concentration increased when using the B15 blend, the total toxic equivalent (TEQ) concentration was not different for both fuels.

► Particulate and 16 priority PAH emissions from diesel and biodiesel B15 combustion were measured. ► No difference in particulate matter mass emitted was found. ► The concentrations of 8 priority HAP were lower when using B15. ► No significant difference in the total toxicity equivalent concentration was found.