What is a common filter media used in HEPA filters?

Borosilicate glass fiber is commonly used in HEPA filters due to its unique properties that enhance filtration efficiency. This material is known for its high tensile strength and effective filtration capabilities, allowing it to capture a broad range of particulate sizes, including very small particles that are often a concern in air quality management.

The structure of borosilicate glass fiber allows for a large surface area while remaining lightweight, which improves airflow while maintaining optimal filtration performance. This is particularly important in applications where high levels of air purity are required, such as in hospitals, laboratories, and cleanrooms.

In contrast, options like polyester fiber, while useful in other types of filters, do not provide the same level of filtration efficiency for very fine particulates as borosilicate glass fiber. Similarly, activated carbon is primarily used for chemical adsorption rather than particulate filtration, and cellulose paper is less effective in high-efficiency applications due to its susceptibility to moisture and degradation over time. Thus, borosilicate glass fiber stands out as a preferred choice in the construction of HEPA filters.