Silencers are typically designed as noise reduction devices using absorbent materials according to different noise reduction principles. They are used in ventilation and air conditioning systems to reduce aerodynamic noise generated by fans and prevent noise from spreading into the air conditioning rooms. Air purification systems usually do not install silencers and instead opt for other comprehensive measures to meet the requirements of the air purification system. If a silencer is necessary, it should be selected with structures and noise reduction materials that are not prone to dust generation and accumulation, such as perforated plate silencers.