An air purifier filter traps airborne particles to improve indoor air quality. The most common and effective type is a HEPA (High-Efficiency Particulate Air) filter, which removes at least 99.97% of dust, pollen, mold, bacteria, and smoke particles as small as 0.3 microns. Other filters include activated carbon filters, which absorb odors and gases, and pre-filters that catch larger particles. Filters should be checked and replaced regularly, typically every 3-12 months, to maintain efficiency and address symptoms like allergies and asthma.
HEPA: Captures at least 99.97% of particles with a diameter of 0.3 micrometers (μm).
HEPA filters work via three mechanisms:
Interception: Particles moving along the airflow stick to the filter fibers.
Impaction: Larger particles directly hit and embed in the fibers.
Diffusion: Very small particles are delayed by colliding with each other and the gas molecules, increasing their chances of being caught.
