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Rostedt A.,Tampere University of Technology | Arffman A.,Tampere University of Technology | Janka K.,Pegasor Oy | Yli-Ojanpera J.,Tampere University of Technology | Keskinen J.,Tampere University of Technology
Aerosol Science and Technology

The Pegasor PPS-M sensor is an electrical aerosol sensor based on diffusion charging and current measurement without particle collection. In this study, the role and effect of each component in the instrument is discussed shortly and the results from a thorough calibration measurements are presented. A comprehensive response model for the operation of the PPS-M sensor was developed based on the calibration results and computational fluid dynamics (CFD) modeling results. The obtained response model, covering the effects of the particle charger, the mobility analyzer, and both diffusion and inertial losses, was tested in the laboratory measurements with polydisperse test aerosols, where a good correlation between the model and the measured results was found.Copyright 2014 American Association for Aerosol Research © 2014 American Association for Aerosol Research. Source

Jarvinen A.,Tampere University of Technology | Kuuluvainen H.,Tampere University of Technology | Niemi J.V.,Helsinki Region Environmental Services Authority HSY | Niemi J.V.,University of Helsinki | And 7 more authors.
Urban Climate

Urban air contains considerable amounts of harmful gaseous substances and aerosol particles. In this study, a recently introduced diffusion charger based PPS-M particle sensor (Pegasor Oy, Tampere, Finland) was evaluated for outdoor air quality measurements in urban environment. The PPS-M particle sensor was used in two stationary air quality measurement stations, one located in the roadside environment and the other in residential area, and in a mobile laboratory. The sampling of urban aerosol to the PPS-M sensor was performed without any pre-conditioning of aerosol. The sensor response to PM2.5 varied between the measurements, being between 7 and 30fA/(μg/m3) depending on the aerosol source. The highest PM2.5 response was observed in the roadside study for exhaust particles while the lowest PM2.5 response was observed for large long range transported aerosol particles having relatively large mean particle size. The sensor signal was found to produce very linear response, with only minimal deviation, to the lung deposited particle surface area concentration (from 4.5 to 6fA/(μm2/cm3)) and to the condensation sink of urban air particles (from 1.0×104 to 1.2×104 fAcm3). The sensor response to particle number concentration was defined to be 0.0044fA/(1/cm3) in roadside environment. In this environment, the signal was found to correlate also with NO and NO2 concentrations of roadside air due to the same origin of particulate and gaseous pollutants. Similar correlation between NOx and the PPS-M signal was not observed in residential area. © 2014. Source

Pegasor Oy | Date: 2011-12-28

The present invention relates to an apparatus (

Amanatidis S.,Aristotle University of Thessaloniki | Ntziachristos L.,Aristotle University of Thessaloniki | Samaras Z.,Aristotle University of Thessaloniki | Kouridis C.,Emisia SA | And 2 more authors.
SAE Technical Papers

The effect of "Start & Stop" and "Gear Shift Indicator" - two widespread fuel saving technologies - on fuel consumption and particle emissions of a Euro 5 passenger car is evaluated in this paper. The vehicle was subjected to a series of different driving cycles, including the current (NEDC) and future (WLTC) cycles implemented in the European type approval procedure at cold and hot start condition and particle number was measured with an AVL Particle Counter. In addition, we have utilized two Pegasor Particle Sensor units positioned in different locations along the sampling line to assess the impact of the sampling location on the particle characteristics measured during highly transient events. The results showed that the particle number emission levels over the WLTC were comparable to the NEDC ones, whereas NOx emissions were more than twofold higher. Both fuel saving technologies can lead to reduced fuel consumption and, subsequently CO 2 emissions, in the order of 5%. However, their impact on particle emissions was not straightforward, as the impact of the DPF loading was found much more significant than the effect of these technologies. However, in several occasions, the frequent start and stops of the engine actually led to an increase in particle emissions over the baseline. On the other hand, the reduced engine speed imposed when the gear shift indicator was respected generally led to lower particle emissions. Transient impacts on particle emissions such as those resulted by the fuel saving technologies studied can be much better monitored with raw exhaust sampling than following the type approval sampling procedure. This recommendation tends to be forgotten in regular research works. Copyright © 2014 SAE International. Source

Ntziachristos L.,Aristotle University of Thessaloniki | Amanatidis S.,Aristotle University of Thessaloniki | Samaras Z.,Aristotle University of Thessaloniki | Janka K.,Pegasor Oy | Tikkanen J.,Pegasor Oy
SAE International Journal of Fuels and Lubricants

The Pegasor Particle Sensor (PPS) is a small and lightweight sensor that can be used directly in raw exhaust to provide the mass and number concentration of exhaust aerosol. Its operation principle is based on the electrical charging of exhaust aerosol and determination of particle concentration by measuring the charge accumulated on the particles. In this paper we have applied the PPS in a variety of vehicle exhaust configurations to evaluate its performance characteristics. First, the output signal of the instrument was calibrated with diesel exhaust to deliver either the mass or the number concentration of exhaust aerosol. Linear response with the soot mass concentration measured by a Photo Acoustic Soot Sensor and number concentration measured by an Electrical Low Pressure Impactor was established. Based on this calibration, the instrument was then used to measure particle concentrations at levels produced by a gasoline direct injection vehicle and diesel exhaust filtered by particle filters of variable efficiency. Hence, the complete range of concentrations and particle characteristics typically encountered in automotive exhaust has been examined. The results show that the PPS signal can provide a repeatable measurement of aerosol concentration in the exhaust of current vehicles, offering a very good correlation both to the mass and number of particles, as measured by existing techniques. Copyright © 2013 SAE International. Source

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