Vasthi PM 10 and PM 2.5 Particulate Matter Monitors works Principle of Particulate matter10 analyzer uses the technology: Ambient particulate matter, Beta –ray detector for measuring the Particulate concentration matter whose aerodynamic equivalent diameter is smaller than 2.5/10μm on rolled filter tape. The instrument adopts low-radiation C14 as the radioactive source. The emitted β-ray passes through the filter membrane with contaminants and will be received by the detector. The detector[1] comprises a photo-multiplier tube (or Geiger detector), a plastic scintillator, and a counter. The thickness can be analyzed quantificational according to the β-ray energy that the detector received. Then the PM 10 and PM 2.5 concentrations in the air can be calculated received, and then the pm 2.5 and pm 10 concentrations in the air can be calculated.