Comprehensive Emission Characterisation of Exhaust from Alternative Fuelled Cars

New renewable and alternative fuels are introduced in the transport sector. Valid and comparable data is needed both on the direct and indirect effects of the new technologies to enable wide-ranging decision-making to increase competitiveness of the best low-emission technologies and to avoid investment in the harmful development, which could lead to new emission related problems. For alternative fuels, composition of the particulate matter (PM) and semivolatile organic compounds (SVOCs) can be very different from that for the traditional fuels. Toxicity, mutagenicity, and carcinogenicity of samples can also vary. The goal here is to investigate comprehensively the exhaust gas from cars using alternative fuels.The results showed differences in toxic emission species between cars using conventional and alternative fuels, as well as between modern cars compared with older Euro 2 diesel cars. As concerns the nitrogen containing species, the NOx and N2O emissions were the highest for the diesel cars, while ammonia emissions were higher for the TWC equipped E10, E85 and CNG fueled cars than for the diesel cars. The methane emission was the highest for the CNG car, while the other hydrocarbon emissions were the lowest for CNG and diesel cars. For the E85 fuelled car, the hydrocarbon emissions composed mostly of methane and ethene, while for the E10 fuelled car the aromatic compounds were dominating. The aldehyde (particularly formaldehyde) emissions were the highest for the Euro 2 diesel car, while the lowest for the Euro 6 diesel car having DPF. E85/FFV had high acetaldehyde and ethanol emissions.The highest PM and solid particulate number emissions were measured for the Euro 2 diesel car, and the lowest for the CNG and the Euro 6 diesel cars. SVOC emissions were higher than the PM emissions for all cars, however, heavier PAHs were present mainly in PM. The CNG and modern diesel cars were the lowest PAH emitters, while the highest PAH emitters were the older diesel and the Euro 6 E10 and E85 fuelled cars. All the PM samples were mutagenic with the highest response for the Euro 6 E10 fuelled car. The SVOC samples were mutagenic at tested concentrations only for diesel cars. Considering the oxidative potential for both PM and SVOC phases, the diesel cars had the highest level. One Euro 6 diesel car indicated potentially harmful SVOC emission that would deserve further studies.