APDA-371 Ambient Dust Monitor


Particulate matter contaminates our atmosphere in various ways. It can for instance be generated by different industrial production processes,waste combustion, coal mining or automobile exhausts. The APDA-371 automatically measures and records airborne particulate concentration levels (in milligrams or micrograms per cubic meter), using the industry-proven principle of beta ray attenuation. Each hour, a small carbon-14 element emits a constant source of high-energy electrons (known as beta rays) through a spot of clean fillter tape. These beta rays are detected and counted by a sensitive scintillation detector to determine a zero reading. The APDA-371 automatically advances this spot of tape to the sample nozzle, where a vacuum pump then pulls a measured and controlled amount of dust-loaded air through the !lter tape. Hourly this dirty spot is placed back between the beta source and the detector thereby causing an attenuation of the beta ray signal which is used to determine the mass of the particulate matter on the filter tape.

The APDA-371 Air Pollution Dust Analyzer for Suspended Particulate Matter (SPM) ensures long term stability and self-diagnostic capabilities as well as efficient collection of fluorine resin tape. The measurement principle operates according to EU and EPA regulations and is also type approved by TueV.


  • Long term unattended remote operation of up to 60 days.
  • Automatic hourly span checks.
  • Data retrieval through RS-232 serial ports using direct PC connections, modems, printers, or digital data collection systems(Option).
  • Direct data logging into Compact Flash Card is optionally available.

Manufactured by HORIBA



Beta Ray attenuation




0-1,000mg/m3(standard), 0-1.000µg/m3

0-200/0-250/0-500/2.000/5.000/10.000µg/m3(special application)


±2.0% of F.S. at 1000/5000/10000μg/m3 range


±3.0% of F.S. at 1000/5000/10000μg/m3 range

Zero Drift

±20μg/m3/day at 200/500/1000/5000/10000μg/m3

Span Drift

±30μg/m3/day at 200/500μg/m3 range

±3.0% of F.S. at 1000/5000/10000μg/m3 range

Measurement time

1 hour

Sample gas flow rate

Approx. 16.7L/min


Tape failure, Flow rate failure, etc.


0-1 V, pulse signal, Contact Input/Output(Range, Power failure, alarm, etc.)

Option: RS-232C, LAN connecting terminal(TCP/IP)


AC100 VAC± 10V, 50/60 Hz, approx. 200VA


430(W) x 483.5(D) x 266(H) mm


approx. 19kg for SPM monitor

approx. 5kg for sampling pump