A microscopic particulate matter counter is an instrument specifically designed to detect, quantify, and categorize the concentration of particulate matter.
Different types of microscopic particulate matter counters that employ distinct principles for particle detection are available; some are discussed in this section:
E) Optical Particle Counters (OPC): These devices use light scattering or light-blocking techniques for detecting particles when they pass through a detection zone. An Optical Particle Counter can provide real-time measurements of the number and size distribution of particles in the sample.
Check the video to learn how Optical Particle Counters work: https://www.youtube.com/watch?v=F7PkGzt6xr0.
F) Condensation Particle Counters (CPC): A CPC condenses vapor, enlarging its size and enabling its detection and quantification. CPCs are highly sensitive to ultrafine particles.
Check this video to learn about the functioning of Condensation Particle Counters: https://www.youtube.com/watch?v=Msu-9YgvjCs
G) Beta Attenuation: A Beta Attenuation Mass Monitor (BAM) or Beta Attenuation Particle Mass Monitor (BAPMM) is used to determine the mass concentration of particulate matter and works on beta radiation attenuation through the filter. The instrument contains a beta radiation source, Strontium-90 (a radioactive isotope), which emits beta particles. The sample is drawn into the device through a filter, and the particulate matter gets deposited on the filter. When the emitted beta particles pass through the filter, the radiation is absorbed by the particles, reducing the intensity of the radiation.
H) Gravimetric Method: The particulate matter is collected on filter paper and weighed to determine its mass. This method is considered a reference standard for PM measurement and is mainly used for regulatory compliance.
Check this video to learn about the Gravimetric method: https://www.youtube.com/watch?v=KlFfuaSbybQ.
I) Scanning Mobility Particle Sizers (SMPS): SMPS is an advanced instrument used to measure the size distribution of particulate matter. It is highly effective in providing insights about the different sizes of particles and their concentration. The SMPS distinguishes particulate matter based on its electrical mobility, which is influenced by size and charge.
Check this video to learn more about SMPS: https://www.youtube.com/watch?v=esfmVsFrzVE.
These particulate matter counters are often used to check air and water quality, along with R&D purposes. Monitoring particulate matter is important because exposure to high levels of specific particle sizes might have adverse effects on the health of human beings, primarily respiratory and cardiovascular systems.