How does PM 2.5 sensor work?

Overview of PM2.5

PM2.5 is particulate matter in ambient air with an aerodynamic diameter less than or equal to 2.5 microns, also known as fine particulate matter or lung-enterable particulate matter. Its diameter is very small, less than 1/20 of the thickness of a human hair, so it can be suspended in the air for a long time and can directly enter the lungs, causing a greater impact on human health.The main sources of PM2.5 include residues emitted through combustion in the processes of daily power generation, industrial production, automobile exhaust emissions, dust, and by-products of various chemical reactions, which contain toxic substances such as heavy metals. Most of these residues contain heavy metals and other toxic substances.

Due to its tiny size, PM2.5 can penetrate into human lungs and even enter the blood circulation, posing a serious threat to human health, such as triggering respiratory diseases and cardiovascular diseases.

PM2.5 Sensor Overview

A PM2.5 sensor is a sensor used to measure the concentration of PM2.5 in the air. It usually consists of optical or electronic components that can detect and measure the concentration of PM2.5 particles in the air in real time and accurately. Such sensors have a wide range of applications in air quality monitoring, environmental monitoring, industrial control and other fields.

PM2.5 sensor working principle

1. Optical Detection Method: This is the most common method and the sensor has a light source and a photosensitive element inside. When the air passes through the sensor, the light source will irradiate the particles in the air, and the photosensitive element will detect the change of light intensity after passing through the particles. Because PM2.5 particles scatter and absorb light, the decrease in light intensity is proportional to the concentration of particles.

2. gravimetric detection: this method calculates the concentration of particulate matter by collecting a certain volume of air samples and depositing the particulate matter in the samples on a piece of filter paper, and weighing the difference in weight before and after weighing the filter paper.

3. Capacitance Detection Method: This sensor detects the concentration of PM2.5 by using the principle that the capacitance value changes when particulate matter passes between the poles of a capacitor.

The working principle of PM2.5 sensors is mainly based on light scattering method or laser turbidity method. The following is the workflow based on the light scattering method:

1. Sampling: Inside the sensor there is a miniature fan which is used to draw in the outside air so that the airborne particles enter into the sensor.

2. Light Scattering: There is a laser light source inside the sensor that scatters light from the airborne particles as they pass through the laser beam. The intensity of the scattered light is proportional to the concentration of the particulate matter.

3. Detection: A photodiode receiver collects this scattered light and converts it into an electrical signal.

4. Calculation: The internal circuitry of the sensor converts the electrical signal into a particle concentration value.

5. Output: Finally, the sensor outputs the results to the device display or wirelessly to other devices.

Summary

PM2.5 is a fine particulate matter in the air that is harmful to human health, and its concentration directly reflects the quality of air. PM2.5 sensor is a device that can accurately measure the concentration of PM2.5 in the air in real time, and its working principle is mainly based on the light scattering method. With PM2.5 sensor, we can understand and monitor the air quality in time, so that we can take appropriate measures to protect our health and environment. PM2.5 sensors play an important role in air quality monitoring, environmental monitoring, industrial control and other fields.

PM2.5, PM10, Integrated Sensor Data Sheet

NBL-W-PM25-PM10-Integrated-sensors-Manual.pdf