The developments concerned novel measurement instrumentation, the sampling methodologies, the knowledge on the nature of sub-23 nm particle emissions and the effect of engine/fuel technologies on particle emissions.
The target of the project was to develop measurement technologies, capable of accounting for sub-23 nm particles regarding number concentration, size and composition of particles. The Induced Current Aerosol Detector (ICAD), developed in SUREAL-23 is based on the fact that the conductivity of an aerosol after unipolar charging is approximately proportional to particle number concentration. ICAD provides particle number concentration, including sub-23 nm particles (down to 10 nm), in real-time and is capable for onboard measurements with high accuracy, repeatability and durability, comparable to the most advanced state-of-the-art systems. Also, the instrument requires minimal or no dilution system (i.e. no VPR) since it can measure hot samples (up to 180oC). The minimum dilution requirements, together with the minimal space and power requirements, making it ideal for PEMS applications. The Advanced Halfmini Differential Mobility Analyzer (HM-DMA), a super-critical DMA also developed in SUREAL-23, provides size-specific measurements. It demonstrated unprecedented resolution and extremely fast response. Even more importantly, the instrument is also capable of hot measurements calling for minimal sampling requirements without the losses and artefacts originating from the complexity of those systems. The losses and artefacts dominate the 10-23 nm particle size range, and therefore the above feature is of utmost importance. In the frame of SUREAL-23 project requirements, a variable wavelength UV photoelectric charger (UV-PEC) setup was designed and constructed for compositional studies of sub-23 nm particulate emissions. The instrument is able to reveal the Poly-Aromatic Hydrocarbons (PAHs) content on the particles' surface. PAHs are the key factors associating particle emissions with health risk. The device is also capable of real-time measurements and therefore.
SUREAL-23 extensively studied the nature of sub-23 nm particles. The effect of particular conditions on the sub-23 particle number concentration and the volatile content has been examined. The advancing of the particle sampling and treatment systems took place also within SUREAL-23 with the construction of a Catalytic Stripper (CS) for volatile particle removal.
An extensive test matrix was performed in engine dynos, chassis dynos and on-road (PEMS). It enabled to form a report documenting the project's recommendations in the light of coming regulations.
The project's results have been communicated through various dissemination and communication activities. SUREAL-23 managed to capitalise its research findings and reach a wide range of stakeholders including the public, scientists, policymakers and industry (9 papers to peer-reviewed journals, 31 participations in conferences and workshops, organisation of two very successful workshops, personnel training and links to the other relevant projects with joint testing campaigns).