A HEPA filter, or High-Efficiency Particulate Air filter, is a type of air filter designed to trap very small particles. It can capture at least 99.97% of particles that are 0.3 microns in size, including dust, pollen, and pet dander. This makes HEPA filters popular in various applications, such as air purifiers, vacuum cleaners, and HVAC systems. HEPA filters work by forcing air through a dense mat of fibers, which physically traps particles. They are essential for improving indoor air quality, especially for individuals with allergies or respiratory issues. Regular maintenance and replacement of HEPA filters are necessary to ensure their effectiveness.