Particle counters are specialized gadgets that count particles they detect, one at a time. They utilize three different methods of counting. The first type is aerosol counter, which monitors the quantity of fragments in the air. It counts and sizes particles in the surrounding air, thus determines the quality of breathing air. Such devices are most commonly used in special scientific and industrial buildings that need to monitor the excessive amount of harmful particles. Another possible application of such device is a cleanroom, a special premise where decontamination before entering a sealed clean environment is taking place. There are gadgets that are used for liquids, they are needed to monitor the quality of a fluid that passes through them. Certain liquids have a set particle limit they need to maintain to be considered clean and be appropriate for usage. An example would be fuel or water. Such gadgets are utilized at pumping stations and sophisticated filter systems. Solid counters are required to measure dry elements like rocks or building materials. These devices are utilized in food, building industry and science.

There are three main techniques used in particle counting. The first one is called light obscuration. Devices with this working principle quantify the light a particle blocks and establish its size. The second method is called light scattering, it’s based on measuring the amount of light that was redirected by a fragment. This method is used for detecting extra-small fragments. The third method is known as direct imaging, where a laser is used to illuminate particles, and then a sensor measures the area of the illuminated particle.