What is a pm sensor?

PM sensor, the full name is particulate matter sensor, can be called PM2.5 PM10 sensor or dust sensor according to the detection object. It is a device used to measure and monitor particulate matter (such as dust, smoke, pollutants, etc.) in the air. This kind of sensor is widely used in air quality monitoring, environmental monitoring, industrial process control and other fields.

Particulate matter under light
Particulate matter under light

The dangers of PM

When the human body breathes, most PM with a diameter of more than 10 μm is deposited in the nasopharynx through impact, while dust with a diameter of less than 10 μm can enter the deep part of the respiratory tract. Most of the dust deposited in the alveoli is fine particulate matter below 2.5 μm (PM2.5).

PM2.5 fine particles have a small diameter, remain suspended in the atmosphere for a long time, spread over long distances, and usually contain toxic and harmful substances, so they have a greater impact on human health. PM2.5 can enter the lungs and blood. If it contains germs, it will cause greater harm to the human body, including our respiratory system, cardiovascular system, and even the reproductive system.

Laser Dust Sensor FS00201

PM Sensor sensor working principle

PM sensors usually use optical principles to measure particulate matter. The optical principle mainly uses the principles of light scattering and absorption to estimate the concentration of particulate matter by measuring the degree of light scattering and absorption by particulate matter.

In optical principles, PM sensors usually contain a light source and a light detector. As air passes through the sensor’s measurement area, particles scatter and absorb light. Photodetectors receive scattered and absorbed light and convert it into electrical signals. By measuring the strength of the electrical signal, the concentration of particulate matter can be deduced.

Common optical principle sensors include laser scattering sensors and infrared absorption sensors. Laser scattering sensors use laser light to illuminate the air and measure the intensity of scattered light to estimate the concentration of particulate matter. Infrared absorption sensors use the absorption of infrared light by particulate matter when infrared light passes through the air to estimate the concentration of particulate matter.

Laser Dust Sensor FS00202

PM sensor performance indicators

  1. Range: Indicates the range of particle concentration that the PM sensor can measure, usually expressed in terms of mass concentration or number concentration.
  2. Resolution: Indicates the smallest particle size or concentration change that the sensor can resolve.
  3. Accuracy: Indicates the accuracy of sensor measurement results, usually expressed as error or deviation.
  4. Response time: Indicates the time it takes for the sensor to start measuring and output stable results.
  5. Stability: Indicates the stability of the output results of the sensor during long-term operation.
  6. Environmental adaptability: Indicates the sensor’s adaptability under different environmental conditions, such as temperature, humidity, pressure, etc.
  7. Maintenance cycle: Indicates the length of the cycle in which the sensor needs to be cleaned or replaced regularly.
  8. Application scope: Indicates which fields or application scenarios the sensor is suitable for.
  9. Other special properties: such as anti-interference ability, explosion-proof performance, etc.