Title : Understanding the links between biofuel composition and regulated and unregulated tailpipe emissions, and potential effects on air quality
The drive to move away from fossil fuels for transportation is leading to increasing use of ‘bio’ components in market fuel, such as the ethanol in E10 gasoline. If sourced responsibly, these can lead to reduction in lifecycle carbon dioxide emissions. However, the difference is composition may also lead to a variation in the concentration of pollutants emissions in the tailpipe post-combustion. While some pollutants may reduce, others could increase, or new pollutants may be generated. This is a particular issue with regard to volatile organic compounds (VOCs) – typically, hundreds are present in the exhaust and can potentially have health effects even at low concentrations. Further, they may go on to react in the air to create smog and secondary organic aerosols, both of which can worsen air quality.
The presentation will contain original data from Emissions Analytics’ test programme, putting together analysis of the organic components in the original fuel with the organics in the resulting exhaust flow. The test programme uses two-dimensional gas chromatography coupled with time-of-flight mass spectrometry in order to fully separate, identify and quantify organic compounds from C2 to C44. Results will particularly focus on the presence of aldehyde emissions resulting from the oxygenated compounds in the fuel. The potential secondary organic aerosol and smog formation will also be quantified.
Finally, the effects on regulated and unregulated emissions will be compared. While some alternative fuels may be beneficial in terms of regulated pollutants, the opposite could be true for unregulated. This would raise a dilemma for regulators that needs to be understood. This is particularly relevant in context of the forthcoming Euro 7/VII regulations, which include no speciated VOCs in the proposed light-duty, and limited VOCs for heavy-duty.