Results that enable you to do more

Pegasor's technology is versatile. It can be used in various ways from measurement to continuous monitoring. It's a technology that simply does more.


Pegasor Particle Sensor technology is a unique development from Pegasor Oy, Finland. It is based on company’s proprietary technology, including various pending patents.

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Key features that enable long term monitoring of fine particles

  • Price and usability meets industrial requirements
  • Real-time operation
  • Continuous operation
  • Particle number and mass
  • Sensitive to fine particles and small particle concentrations


Principle of operation

Pegasor sensor technology is based on the measurement of electrical charge carried by particles. It is a non-collecting measurement method, which is unique compared to conventional fine particle, especially soot nanoparticle measurement techniques. The non-collective feature ensures long maintenance and cleaning interval and thus Pegasor sensors can be used in monitoring applications where essentially service-free operation is required.
Pegasor sensor comprises an ejector where the motive fluid flow is generated by pure, particle free gas. Typically this gas is filtered air. The motive fluid flow generates an underpressure to the sample inlet and due to the negative pressure, particle-containing gas flows into the sensor. Benefit of not having an ordinary pump in the particle flow stream is again improved lifetime and less need of maintenance.

The clean motive fluid is ionized before it enters the sensor. This ionized air is then used to charge the particles in the sensor. Mixing between the ionized air and the sample flow is very effective and thus all particles are efficiently charged. Particle charging is relative to the particle size.

Ions that are not attached to the particles are removed from the gas flow by an ion trap. The trap is basically an electrostatic precipitator with a small electrical field. As the electrical mobility of the ions is much higher than the mobility of charged particles, the ion trap effectively removes only the ions. However, if required, the ion trap may be tuned to remove also particle smaller than a certain size. This feature is beneficial in some applications.

When the free ions are removed, the only mechanism carrying electrical current is the flow of charged particles. The electrical current escaping from the sensor with the charged particles can be measured and this gives a direct, fast, real-time measurement of the particle concentration. The measurement result can be expressed either or both as mass concentration or as number concentration.


List of most relevant publications

L. Ntziachristos et al., (2009), ’ A New Sensor for On-Board Diagnosis of Particle Filter Operation – First Results and Development Potential, FAD Conference, Dresden, November 4-5.2009.

T. Lanki et al., (2011), ‘An electrical sensor for long-term monitoring of ultrafine particles in workplaces’, J. Phys.: Conf. Ser. 304 012013
L. Ntziachristos et al., (2011), ‘Exhaust Particle Sensor for OBD Application’, SAE Paper 2011-01-0626

M. Besch et al., (2011), ‘Assessment of novel in-line particulate matter sensor with respect to OBD and emissions control applications’, Proceedings of the ASME 2011 Internal Combustion Engine Division Fall Technical Conference, ICEF2011 October 2-5, 2011, Morgantown, West Virginia, USA, ICEF2011-60142

L. Ntziachristos et al., (2013), ‘Application of the Pegasor Particle Sensor for the Measurement of Mass and Particle Number Emissions’, SAE Int. J. Fuels Lubr. 6(2):521-531, 2013, doi:10.4271/2013-01-1561.

Amanatidis, S et al., (2013). "Applicability of the Pegasor Particle Sensor to Measure Particle Number, Mass and PM Emissions," SAE Technical Paper 2013-24-0167, 2013, doi:10.4271/2013-24-0167

M. Maricq, (2013), ‘Monitoring Motor Vehicle PM Emissions: An Evaluation of Three Portable Low-Cost Aerosol Instruments’, Aerosol Science and Technology, 47:5, 564-573.

S. Amanatidis et al., (2014). ’Use of a PPS Sensor in Evaluating the Impact of Fuel Efficiency Improvement Technologies on the Particle Emissions of a Euro 5 Diesel Car’. SAE Technical Paper 2014-01-1601

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