Comparative toxicity of various biodiesel exhaust exposures compared with diesel

Introduction and Aim: Biodiesel (BD) is promoted as a sustainable replacement for commercial mineral diesel. As BD exhaust components change depending on the source oil, the aim of this project was to compare the effects of exposure to exhaust generated by the combustion of diesel (D) and BD made from different source oils. Methods: Primary human airway epithelial cells (n=8, from children aged 2.6-3.4yrs) were exposed for 1 hour to diluted exhaust from an engine combusting D or BD (from soy, canola, tallow, palm and waste cooking oil (WCO)). Exhaust characteristics were analysed and health impacts including viability and inflammatory mediator release were assessed. Results: Exhaust gas composition varied significantly between fuels with soy BD containing the highest levels of NOx and CO2. Particle size spectra also differed between exhaust types with all BD exhausts displaying peaks of varying intensity in the ultrafine particle size ( Exposure to WCO exhaust resulted in significant cell death (p Conclusion: The majority of BD exhausts contained more and smaller particles and more toxic gases compared with D and the health impacts varied between BD types with WCO, canola and tallow BD causing the worst health effects. Grant: ARC-DP170104346.