The particulate system is made up of three separate modules:
- An optical engine for measuring the particulate. There are two types of optical engine:
- the particle monitor uses a nephelometer combined with a sharp cut cyclone and measures a single size fraction: TSP or PM10 or PM2.5 or PM1.
- the particle profiler uses an optical particle counter (OPC) and measures four size fractions simultaneously: TSP and PM10 and PM2.5 and PM1. It doesn’t use a sharp cut cyclone.
- An electronics module for handling the data transfer.
- A pump module for controlling the flow rate.
The particle monitor has an international performance certification (MCERTS) and is more accurate than the particle profiler.
The sample flow for the particle monitor and particle profiler is separate from the gas sample flow. There is a separate pump, a separate inlet and a separate exhaust.
|Particle monitor||Particle profiler|
|Mass outputs||TSP or PM10 or PM2.5 or PM1||TSP and PM10 and PM2.5 and PM1|
|Particle count outputs||No||Yes|
|Accuracy||<± (2 μg/m3 + 5% of reading)||<± (5 μg/m3 + 15% of reading)|
|MCERTS||Yes for PM10||No|
|Factory calibration period||Every two years (24 months)||Every year (12 months)|
|SCAQD 1466 approved||Yes||No|
|Inlet flow rate||2.0 LPM||1.0 LPM|
The particle monitor uses a custom forward light scattering nephelometer to measure particle concentration and a sharp cut inlet cyclone to select the particle size.
There is a different sharp cut cyclone for each particle size designation. TSP is measured by only fitting the TSP inlet and not using a sharp cut cyclone.
AQM 65, AQS 1 and Dust Sentry monitors can be configured with one particle monitor to measure a single particle size.
The three modules are positioned in the top right corner of the enclosure – optical engine on the far right, pump in the middle, and the electronics module on the left.
Sample and purge filters are located inside the optical engine.
An AQM 65 can be configured with two particle monitors to measure two size fractions at the same time. All six modules are lined in a row at the top of the monitor.
Outside the enclosure, the PM10 inlet is fitted on the right and the PM2.5 on the left.
The particle profiler uses an optical particle counter to measure four particle size fractions simultaneously. There is no sharp cut cyclone – both the concentration and size are measured inside the optical particle counter. Only the TSP head is fitted to the top of the inlet tube.
AQM 65, AQS 1 and Dust Sentry Pro monitors will only ever have one particle profiler installed. The three modules are positioned in the top right side of the enclosure – optical engine on the far right, pump in the middle, and the electronics module on the left. The sample and purge filters are mounted on the inside of the pump module.
Before July / August 2018 (when there was a change to the pump module), the filters were between the pump module and optical engine.