Update: 2020-12-07 17:05 Source: LUFTMY
Air particulate pollutants are composed of particulate matter, acid droplets, organic chemicals, metals, soil, or dust.Moreover, the size of particulate air pollutants is associated with the risk of disease, and the smaller the size, the greater the risk.Particles smaller than 10 microns (PM10) -- about one-eighth the diameter of a human hair -- can travel through the throat and into the lungs, causing serious health problems.
When the particles are smaller than 2.5 microns (PM2.5), they are more harmful and can enter deep into the lungs, where the body cannot naturally avoid them.The particles are too large for the body's immune system to handle, but they are small enough to penetrate deep into the respiratory system.Therefore, the sensor is currently the only one that can detect the weight of particulate matter and provide the mass concentration.
Particulate matter sensors commonly used include PM10 sensors and PM2.5 sensors, and sensor principles commonly used include laser principle and infrared principle.
Infrared principle PM2.5 sensor
Particles and molecules can scatter light and absorb some of the energy of the light.When a beam of parallel monochromatic light is incident into the measured particle field, it will be affected by the scattering and absorption around the particle, and the light intensity will be attenuated.The relative attenuation rate of incident light passing through the concentration field to be measured can be obtained.The relative decay rate can basically linearly reflect the relative concentration of dust in the field under test.The intensity of the light is directly proportional to the intensity of the electrical signal converted by photoelectric. By measuring the electrical signal, the relative attenuation rate can be obtained, and then the concentration of PM2.5 in the field to be measured can be determined.
Infrared principle PM2.5 sensor selection recommendation: GDS06 Infrared PM2.5 Sensor Model
Laser principle PM2.5 sensor
Using Mie Mie spherical particle scattering principle, namely the laser sensor using laser light scattering produces on the suspended particles in the air, the photoelectric detector in a certain way within the scope of collecting scattering intensity, will receive the scattering intensity linear converted into voltage, and then into a data processing system, data processing system according to the program in advance according to the Mie scattering theory for data processing, it is concluded that the equivalent grain size of particles of different size particles per unit volume and concentration.
Laser principle PM2.5 sensor selection recommendation: LD12 Laser PM2.5 Dust Sensor Model