PM2.5 refers to dust particulate matter suspended in the air with a diameter of approximately 2.5 micrometers, also known as fine particulate matter. Due to its small diameter, it easily accumulates in the lungs after entering the human body and causes harm. The PM2.5 content in the air can typically be detected using a sensor.

There are several main principles for PM2.5 sensors to measure air. One of them is the Beta-ray method, which collects PM2.5 onto a filter paper and then irradiates it with a beam of Beta rays. The rays are attenuated as they pass through the particulate matter, and the degree of attenuation is proportional to the weight of the particles. The weight of PM2.5 can be calculated based on the attenuation of the rays. Principle of β-ray absorption: When an atomic nucleus undergoes β-decay, it releases β-particles. A β-particle is actually a high-speed charged particle with strong penetrating power. When it passes through a certain thickness of absorbing material, the phenomenon where its intensity gradually weakens as the thickness of the absorbing layer increases is called β-absorption.

The advantage of the Beta-ray method is high accuracy and a high correlation between the sensor signal and particulate mass. The disadvantage is the slow response speed, so usually only its hourly average value is used.

Application areas for Luftmy PM2.5 sensors: air purifiers, air conditioners with purification functions, PM2.5 detectors, range hoods, smoke alarms, fresh air systems, specialized PM2.5 sensors, air detectors, etc.