Particle number periodic technical inspection (PN-PTI) has been implemented in several european countries to detect defective diesel particulate filters (DPF) and remove high emitting vehicles from the roads. Gasoline direct injection (GDI) engines are equipped with similar gasoline particulate filters (GPF) which would also benefit from PN-PTI however, it is not yet clear that existing PN-PTI devices can also accurarely measure GDI exhuast due to differences in humidity and particle size. In this study, we examine the effectiveness of existing PN-PTI devices approved for use in Switzerland to detect particles in GDI exhaust in the laboratory and real exhaust.

This study aims to characterize the performances of each among three alcohols to be used in the saturator inlet of a WCPC prototype (model ADI-2021-1, Aerosol Dynamics Inc.) for the detection of sub-5nm naturally charged flame-formed carbonaceous materials. The usage of either nBA, IPA, or EtOH in the saturator inlet results in three different CPC devices relying on two-component condensation, namely the nBA-WCPC, the IPA-WCPC, and the EtOH-WCPC, respectively. The detection efficiency of those two fluid devices is assessed under various flow rates and temperature operating conditions.

This study presents a condensation diffusion charger (CDC) that combines a condensational droplet magnifier with a diffusion charger for particle number counting. Using diethylene glycol, it detects particles down to 2.5 nm with a size-independent response from 10 to 150 nm. Simulations and experiments confirmed droplet growth to ~2 µm, enabling a 20 times signal amplification. The CDC achieves a detection limit of <50 #/cm³ and an upper range of >10⁶ #/cm³. Tested on a chassis dynamo with a motorcycle, it showed strong correlation with a reference CPC (R² = 0.94), demonstrating its accuracy and reliability in particle number detection.

In the standardized calibration method for Differential Mobility Analyzer (DMA), monodisperse aerosols with electrical mobility diameters selected by a DMA are compared to the diameter of size-certified particles. National Metrology Institutes often calibrate DMAs using PSL particles larger 80 nm to avoid interference from surfactant peak. However, to comply with EU’s vehicle emissions and air quality regulations, it is critical to determine the sizing accuracy of DMAs using certified standard aerosols down to 10 nm. In this study, we use size-traceable silver aerosols to demonstrate the concept of DMA calibration down to 10 nm.

We will present new results from our recently introduced Sublimation Particle Counter (SPC). The advantage of the SPC technique is that it does not require the use of any working fluid to measure the total number concentration.

Initial measurements with this new method showed that the total number concentration of the SPC has a good correlation with a CPC for up to 10⁵ cm^-3 nebulised NaCl particles. We also observed a very similar lower cut-off size for NaCl aerosol, but with a much steeper slope from the 90% counting efficiency diameter D90 to the 50% counting efficiency diameter.

This study presents performance evaluation of a CEN-SMPS (CEN/TS 17434 (2020)) that will be used to identify high emitters vehicles in MITRAP project using a combined metric like total particle number (TPN) vs. solid particle number (SPN) . As the introduction of new European emission standards like Euro 6 have led to decrease in the GMDs of transport emissions (50-60 nm), the SMPS was evaluated under the novel fast-scanning mode (1-minute) for the scan range 10-237 nm. The SPN measured by the CEN-SMPS were comparatively closer (9-12% underestimation) to the reference CPC as compared to the TPN measured (17-18% underestimation).