LCT – 12


Real-time measurement of PM concentrations (PM2.5 or PM10)

Automatic optical cell cleaning and recalibration system

Multi-year operation

Low running costs

Easy to integrate in environmental monitoring networks

Method of Operation

Qbit’s LCT-12N Particulate Matter (PM) Meter is an instrument based on “Laser Scattering” measurement, that is, the measurement of light scattered by particulate matter in the air sample introduced into an optical interaction cell. This type of measurement allows obtaining a real-time value, i.e., a continuous measurement of the particulate content in air. However, this measurement is not a direct measure of the mass of particulate matter in the air. The amount of light scattered by particulate matter is, in fact, proportional to its density in the air for the same physicochemical properties and particle size distribution. Conversion of the optical data must be carried over to a mass measurement of particulate matter through a calibration process. The mass value of PM is therefore the more accurate the more the sample used in the calibration process is similar to that at the site and time of measurement.

Operating Specifications

Quantity Value Unit Notes
Power supply 12  (o 24) Vdc
Average absorption <5 W With pump flow set at 2.2 l/min
Maximum Peak Absorption 15 W In calibration and with pump flow 3 l/min
Pump flow 0-3 l/min Adjustable by firmware (FW)
Measurement time 1-120 sec Adjustable by FW
Calibration interval 1-600 min Adjustable by FW

Resolution and Accuracy of Measurement Signals:

Quantity Value Unit Notes
PM signal resolution 1/4096 Full Scale (1)
PM signal accuracy <1% Full Scale (2) Over the entire measuring time range
Maximum PM range 10000 μg/m3 (3) Factory settable
Temperature resolution 0.01 °C (4)
Temperature accuracy  0.3 °C (4)
Pressure resolution 0.01 kPa (4)
Pressure accuracy 0.5 kPa (4)
Rel. Humidity resolution 0.04 % (4)
Rel. Humidity accuracy +/- 2 % (4) For Humidity values between 20% and 80%
  1. As indicated at the beginning of this data sheet, the resolution and accuracy data of the PM measurement are relative to the optical signal produced by the particulate sample. The similar specifications on the mass value of particulate matter are derived from a calibration process that is sensitive to the type of sample tested (carbon dust, such as those typically found in winter due to heating systems result in a higher conversion coefficient than silica dust more typical of summer measurements). The accuracy of the mass data, at a specific site and in a specific time period, must therefore be evaluated by comparison over an interval of several hours with a gravimetric measuring system (Primary Method).
  2. The accuracy of the measurement is greater the longer the measurement interval. For measurements longer than 10 seconds, accuracy can reach levels better than 1 part in 1000.
  3. The standard range set at the Factory corresponds to a concentration of 1500 μg/m3 at Full Scale. Which produces for what is stated in (2) a measurement sensitivity better than 2 μg/m3, for measurement intervals of 10 seconds or greater.
  4. Optional


External dimensions (without Cyclone) 25 cm x 20 cm x 10 cm

Weight about 2 kg