%0 Thesis
%9 Doctoral
%A Southern, Daniel
%B Mechanical Engineering
%D 2024
%F discovery:10188594
%I UCL (University College London)
%P 580
%T Influence of biodiesel molecular structure on exhaust particulate-bound PAHs and toxicity to normal human airway epithelia
%U https://discovery.ucl.ac.uk/id/eprint/10188594/
%X Various feedstocks may contribute to biofuel production to reduce greenhouse gas  emissions, however, the toxicity of pollutants produced by combustion of current  biofuels for diesel engines (i.e., fatty acid methyl esters, FAMEs) are poorly understood.  Furthermore, the fatty acid profile of biodiesels varies in the average chain  length and unsaturation. An understanding of the fuel structure effect on particulate  toxicity may provide valuable insight for regulators and fuel researchers.  A series of experiments investigated FAME biodiesel effects on combustion  (in a naturally aspirated single-cylinder direct-injection diesel engine), particulatephase  polycyclic aromatic hydrocarbon (PAH) emissions and toxicity to normal human  primary bronchial epithelial cells (HPBEC). FAME biodiesels from six feedstocks  were chosen because of commercial utilisation (methyl esters of soybean oil,  SME; palm oil, PME; rapeseed oil, RME, and waste cooking oil, WCOME) or contrasting  constituent methyl ester profiles (methyl esters of coconut oil and linseed  oil). The commercial FAMEs were also blended with fossil diesel (B10, B20 and  B50) to investigate whether biodiesel blends affect PAH emissions. In addition,  six single-component fuels (including decene, decane, undecane, dodecane, methyl  dodecanoate and 30/70 v/v% methyl acetate/decene blend) were investigated for  further insight into the effect of molecular structure on PAH emissions. HPBEC  were cultured at the air-liquid interface (>28d) to achieve sufficient cellular differentiation.  Fuel effects on particulate-phase PAH emissions and the mRNA levels of investigated  genes were observed and attributed to an increase in FAME unsaturation.  For example, measures of PAH content (e.g., B[a]P-equivalence, FPC1) correlated with NQO1, ALDH3A1 and IL19 expression, and significant increases of CYP1A1  expression were observed after neat FAME particulate extract exposure. Additionally,  WCOME10, RME10 and SME10 blends emitted higher total particulate-phase  PAH emissions compared to fossil diesel, whereas a contrasting trend was observed  for PME10. Overall, these results support higher particulate toxicity associated with  unsaturated FAMEs.
%Z Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request.