Cancer risk assessment induced by PAH and aldehydes from an automotive diesel engine fueled with renewable fuel blends

The objective of this study was to compare the incremental lifetime cancer risk (ILCR) induced by polycyclic aromatic hydrocarbons (PAHs) and aldehydes emitted by an automotive diesel engine fueled with ultra-low sulfur diesel fuel (ULSD) as reference, 13% of renewable diesel with ULSD (HVO13), and 13% of n-butanol with ULSD (Bu13). The engine was operating at a fixed load, representative of urban driving conditions. Cancer risk was determined by assessing the potential relative to carcinogenic aldehydes and PAH concentrations based on analytical results of samples taken from the tailpipe. Results showed similar PAH profile emissions for all tested fuels, except for those 5 and 6 rings PAH, which showed higher emission with ULSD. Bu13 increased the formaldehyde and acetaldehyde emissions by approximately 4 times compared to ULSD and HVO13, which resulted in a ILCR 3 times higher. It is concluded that unregulated emissions should be carefully assessed prior to promoting the use of butanol/diesel fuel blends as partial substitute of fossil diesel fuel.