The sensor combines a laser nephelometer with a high-precision sharp cut cyclone to give accurate real-time measurement of ambient particulate matter. By changing the sharp cut cyclone the particle sensor can be used to measure PM_2.5, PM₁ or TSP. For simultaneous measurement see the Particle Profiler.

A nephelometer is an optical sensor that uses light scattering from particulate matter to provide a continuous real-time measurement of airborne particle mass. The light source is a visible laser diode and scattered light is measured in the near forward angle using focusing optics and a photo diode. The nephelometer has an on-board temperature sensor that corrects for thermal drift, sheath air filter to keep the optics clean, automatic baseline drift correction, and a fibre optic span system to provide a check of the optical components.

The sharp cut cyclone is a precision-engineered component fitted to the AQM 65 inlet that physically selects particles of a target size e.g. PM₁₀ targets particles <10 microns. This ensures precise measurement of only the size fraction of interest. The inlet is fitted with a heater that is used to remove moisture from the incoming sample. Moisture can reduce the accuracy of optical measurement, so for best results the inlet heater is activated in the event of high humidity.

Compared to reference instruments such as a beta attenuation monitor (BAM) this particle sensor based on nephelomtery is compact, lightweight and costs 3-5 x less to own and operate. In addition, data is measured, logged, and reported at one-minute intervals.

Typical applications include:

Keep calibration up to date without the downtime. Maintaining an up-to-date calibration certificate gives you and project stakeholders confidence in the data from the air monitoring instruments. Our Hot-swap Service makes the process of factory calibration easy. We send you a freshly calibrated module from our stock. You replace the old module with the new one and send the old one back to us. And that’s it – calibration all up to date and zero downtime.