How does a high-efficiency particulate air (HEPA) filter improve air quality in HVAC systems?

A high-efficiency particulate air (HEPA) filter significantly enhances air quality within HVAC systems by capturing 99.97% of particles that are 0.3 microns in diameter. This particular size is critical because it represents the most challenging particle size for traditional filters to capture, which can include dust, pollen, pet dander, mold spores, and smoke. By being able to trap such a high percentage of these fine particulates, the HEPA filter effectively reduces allergens and other harmful pollutants in the air.

This level of filtration contributes directly to improved air quality, making environments healthier, particularly for individuals with respiratory issues or allergies. The efficiency of HEPA filters means that they can significantly reduce the amount of airborne contaminants, leading to cleaner, safer indoor air.

The other options do not address the main function of a HEPA filter in terms of improving air quality. Increasing air pressure does not inherently lead to better filtration; simply replacing old air with fresh air does not ensure that contaminants are removed from the recycled air, and lowering the temperature of the air relates more to thermal comfort rather than filtration.