Biodiesel exhaust: The need for a systematic approach to health effects research

Abstract

Biodiesel is a generic term for fuel that can be made from virtually any plant or animal oil via transesterification of triglycerides with an alcohol (and usually a catalyst). Biodiesel has received considerable scientific attention in recent years, as it is a renewable resource that is directly able to replace mineral diesel in many engines. Additionally, some countries have mandated a minimum biodiesel content in all diesel fuel sold on environmental grounds.When combusted, biodiesel produces exhaust emissions containing particulate matter, adsorbed chemicals and a range of gases. In many cases, absolute amounts of these pollutants are lower in biodiesel exhaust compared with mineral diesel exhaust, leading to speculation that biodiesel exhaust may be less harmful to health. Additionally, engine performance studies show that the concentrations of these pollutants vary significantly depending on the renewable oil used to make the biodiesel and the ratio of biodiesel to mineral diesel in the fuel mix. Given the strategic and legislative push towards the use of biodiesel in many countries, a concerning possibility is that certain biodiesels may produce exhaust emissions that are more harmful to health than others. This variation suggests that a comprehensive, systematic and comparative approach to assessing the potential for a range of different biodiesel exhausts to affect health is urgently required. Such an assessment could inform biodiesel production priorities, drive research and development into new exhaust treatment technologies, and ultimately minimize the health impacts of biodiesel exhaust exposure.

DNA Damage Potential of Engine Emissions Measured In Vitro by Micronucleus Test in Human Bronchial Epithelial Cells

“…In vitro studies analysing the effect of exposure to engine exhaust on induction of MN in mammalian cell lines have not been systematically conducted, even though they have potential to be used for a broad spectrum of new fuels and new engine and exhaust after‐treatment technologies under various operating conditions. An urgent need for a comprehensive investigation of the impact on human health was recently suggested for biodiesel exhaust due to a broad variety of the blends with different ratios of diesel and biodiesel components . Studies related to the in vitro micronucleus test are almost completely missing, and the cell system presented in our study can serve as a suitable model for a broader application of the MN test in future studies.…”

Environmental sustainability of biofuels: a review

“…These differences are small for 5-20% biodiesel blends and would lead to negligible or non-measurable impacts on air quality [294], but increase with higher blends [290]. On the other hand, Larcombe et al [296] argue that, despite having lower PM emissions, biodiesel exhaust emissions could potentially be more harmful to human health because of higher proportion of ultra-fine particles (less than 100 nm diameter) compared to diesel exhaust. This is due to the fact that smaller particles remain suspended in the air for longer, are more easily inhaled and are able to penetrate more deeply into the lungs.…”

Soy Biodiesel Exhaust is More Toxic than Mineral Diesel Exhaust in Primary Human Airway Epithelial Cells

“…Despite the potentially more toxic effects of biodiesel exhaust, most studies comparing biodiesel to commercial mineral diesel instead focus on fuel economy and engine wear, or the physico-chemical differences between the exhausts 4, . Few compare health effects to exhaust exposure 7,10,11 . Those that do primarily use the Ames mutagenic assay 12,13 or immortalized cell lines 8,14 and the majority only focus on the cytotoxic and mutagenic potential of the particulate matter, ignoring the effects of the gaseous components of the exhaust entirely 7,15 .…”