Vehicle particle pollution under the nano-microscope
An EU-funded project is developing a way of measuring polluting particles smaller than 23 nanometres - the smallest size covered by current legislation.
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Poor air quality is responsible for the premature death of around 400 000 Europeans every year and road vehicles are considered a major culprit. The sector accounts for 60 % of particle pollution tiny airborne particles known as PM and 64 % of nitrogen dioxide pollution in urban areas, making the sector critical to improvements in air quaity.
The EU-funded DOWNTOTEN project is advancing research into particle pollution for miniature particles smaller than those covered by current regulations less than 23 nanometres (nm). It is doing so in real driving conditions, not just in the laboratory.
The latest evidence suggests that diesel and, more importantly, gasoline direct injection vehicles emit solid particles smaller than 23 nm. We are developing a method to measure particles smaller than this right down to 10 nm. We hope to inform future EU regulations on these miniature sub-particles and build a marketable emission measuring system, says Zissis Samaras, professor at Aristotle University in Greece, Director of the Laboratory of Applied Thermodynamics and DOWNTOTEN project coordinator.
The project is focusing on particle emissions from the new-generation internal combustion engines with direct injection. In this process, fuel is first highly pressurised and then injected into the combustion chamber of each of the vehicles cylinders, compared to conventional engine technology that injects fuel into the cylinder port and does not require high pressure.
DOWNTOTEN scientists are developing an on-board system that will be able to sample and measure PM smaller than 23 nm under any type of driving conditions on the road for petrol and diesel, hybrid and non-hybrid engines. The measurement protocol will be designed to make sure that non-compliant vehicles do not pass emissions tests.
The team is also collaborating with developers of the next generation of engine technology on how to limit real-driving emissions of tiny particles for diesel and direct injection petrol engines. We hope to demonstrate that low emission levels of nanoparticles are possible with diesel and petrol engines, says Samaras.
More efficient controls
The project will also consider factors that could play a crucial role in determining the amount of particle emissions, including fuel type, lubricants and additives. For example, if the source of some particles is proven to be from engine lubrication oil, then the solution is not necessarily a denser particle filter or an injection system; improving the lubricant should then be considered, explains Samaras.
Meanwhile, researchers will study how particle emissions form, and the physical and chemical properties of any remaining particles once the emissions have passed through a control system. Samaras hopes the research will contribute to the design of more efficient emission control systems for vehicles as well as to the development of robust and effective EU emissions control regulation.
While the project is not studying the potential detrimental health and environmental effects of particulate pollution, its findings on the chemical composition of particle pollution, the timescales of particle formation and the impact of new filter technologies on the chemical properties of particles will also inform scientists in the health and environment sectors.
DOWNTOTEN has set up partnerships with organisations in the USA and Japan to ensure its research and findings on particle emissions have a global influence.