Is denser filter material always better for a filtration-type air purifier?

2024/08/17

Many people believe that the higher the density of the filter material used in an air purifier, the better the purification effect. However, is this really the case? In general, for ventilation filters, the speed at which air passes through the material ranges from 0.13 to 1.0 m/s. The resistance and airflow are not linearly related but follow an upward curve. Increasing the airflow by 30% might increase the resistance by 50%. Filters can capture particles of any form, including droplets. The filtering material is typically porous and has some noise reduction effects. Filters create resistance to airflow and provide some degree of air distribution. Higher density filters can remove smaller dust particles, improving purification, but they also create significant resistance, reducing airflow and affecting purification efficiency. Thus, relying solely on filter media has limitations (it may require increasing fan power, which can lead to noise issues and higher energy consumption, and high-efficiency filters need frequent replacement, increasing consumables). This is similar to wearing a mask; masks that effectively protect against PM2.5 are often less breathable.

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