Air Quality Instrumentation: Part III - Particle Mass (PM) Estimation
In the previous installments, I discussed ISO21501-4 (a standard used during particle counter calibration for the cleanroom industry) and how it served to bring a degree of rigor to air quality measurements in the cleanroom and manufacturing industry. In this installment, we’ll discuss particle mass (PM) estimation in air quality instrumentation.
First of all, let’s look inside some simplified air quality sensors to see how they function. There are two main types of optical air quality sensors: optical particle counters and optical photometers. A general overview and discussion of the limitations and challenges for each type of sensor follow below.