Emissions of intermediate volatility organic compound from waste cooking oil biodiesel and marine gas oil on a ship auxiliary engine.

Ship auxiliary engines contribute large amounts of air pollutants when at berth. Biodiesel, including that from waste cooking oil (WCO), can favor a reduction in the emission of primary pollutant when used with internal combustion engines. This study investigated the emissions of gaseous intermediate-volatile organic compounds (IVOCs) between WCO biodiesel and marine gas oil (MGO) to further understand the differences in secondary organic aerosol (SOA) production of exhausts. Results revealed that WCO exhaust exhibited similar IVOC composition and volatility distribution to MGO exhaust, despite the differences between fuel contents. While WCO biodiesel could reduce IVOC emissions by 50% as compared to MGO, and thus reduced the SOA production from IVOCs. The compositions and volatility distributions of exhaust IVOCs varied to those of their fuels, implying that fuel-component-based SOA predicting model should be used with more cautions when assessing SOA production of WCO and MGO exhausts. WCO biodiesel is a cleaner fuel comparing to conventional MGO on ship auxiliary engines with regard to the reductions in gaseous IVOC emissions and corresponding SOA productions. Although the tests were conducted on test bench, the results could be considered as representative due to the widely applications of the test engine and MGO fuel on real-world ships.