High Efficiency Particulate Air (HEPA) filters are crafted from a dense, fibrous mat typically composed of glass fibers. The production process involves layering these fibers to form a mat with an intricate network of microscopic passages. The fibers are arranged randomly, creating a maze-like structure that traps particles effectively. The filter's efficiency is attributed to its ability to capture particles as small as 0.3 microns in size, including dust, pollen, mold spores, and bacteria.

HEPA filters operate on the principle of mechanical filtration. As air flows through the filter, the particles within it collide with the fibers. Larger particles are trapped through direct interception, while smaller ones are captured by diffusion and inertial impaction. The filter's labyrinthine design ensures that a significant portion of particles is unable to pass through, purifying the air in the process.

The effectiveness of HEPA filters is further enhanced by their large surface area, maximizing the chances of particle capture. These filters are commonly employed in air purifiers, vacuum cleaners, and ventilation systems, providing a crucial line of defense against airborne contaminants. HEPA filtration is especially valuable in environments where maintaining high air quality is essential, such as hospitals, cleanrooms, and homes of individuals with respiratory conditions. In summary, the construction and design of HEPA filters, coupled with their mechanical filtration mechanism, make them a reliable and efficient means of cleaning air by trapping a wide range of particulate matter.