Total carbon characterization and polycyclic aromatic hydrocarbon toxicity assessment for particulate matter produced from Alcohol-Diesel blend

Methanol, ethanol and butanol have emerged as an important alternative fuel for combustion engines due to their inherent advantages like lower particulate matter emission, renewability and lower greenhouse gas emissions in comparison to conventional diesel. Unregulated emission like elemental carbon (EC), organic carbon (OC) and polycyclic aromatic hydrocarbons (PAHs) in the exhaust are important aspects as these components are prone to have carcinogenic effects. The present study deals with the detailed analysis of EC, OC and individual PAHs determination in particulate matter samples of alcohol-diesel blends (methanol, ethanol, butanol and diesel; M, E, B and D) with varying oxygen mass fractions of 2.5% and 5%. The study revealed that methanol-diesel blends (DM2.5 and DM5) reduced the total carbon by -94% and -77% whereas DB5 (-35%) was found to be least effective. DM2.5 also reduced the 4 ring structured PAHs by 6 folds in comparison to diesel while DE5 increased the 5 ring structured PAHs by -35% which carry higher toxicity potential. DE5 showed the highest toxicity potential of -262 benzo[a]pyrene (B[a]P) equivalent in comparison to toxicity potential of -224 B[a]P equivalent of diesel for their sampled particulate matters.