Recently, global COVID-19 data has rebounded, with new variants exhibiting increasing transmissibility and immune evasion capabilities , sounding a new alarm for global public health security. Beyond traditional preventative measures such as vaccines, masks, and social distancing, have we noticed a powerful yet unsung ally? That is the air filtration technology widely used in modern construction and precision industries—HEPA and ULPA filters .
The novel coronavirus, especially Omicron and its variants, primarily spreads through airborne droplets and aerosols. In poorly ventilated indoor environments, tiny aerosol particles carrying the virus can remain suspended in the air for hours, extending transmission distances far beyond social distancing. Faced with this invisible threat, we need tangible barriers. HEPA and ULPA filters were developed precisely for this purpose.
I. The Shield of Protection: A Technical Analysis of HEPA and ULPA
HEPA: High-Efficiency Particulate Air Filter
Standard: Filters particles with a diameter of 0.3 micrometers with an efficiency of at least 99.97%.
Why 0.3 micrometers? This is the “most easily penetrated particle size. ” Particles larger or smaller than this size are more easily captured. Therefore, overcoming the 0.3-micrometer barrier means excellent interception capabilities for both larger and smaller particles.
Relevance to Viruses: The diameter of a single COVID-19 virus cell is approximately 0.1 micrometers, but it cannot exist alone in the air and must attach to larger carriers such as droplet nuclei (typically 1-5 micrometers in diameter). HEPA filters can efficiently capture these virus-carrying droplet nuclei, thus significantly reducing the concentration of viruses in the air.
ULPA: Ultra-High-Efficiency Particulate Air Filter
Standard: More stringent than HEPA, with a filtration efficiency of at least 99.999% for particles with a diameter of 0.1-0.2 micrometers.
Application Scenarios: Primarily used in environments with extremely high cleanliness requirements, such as chip production lines, pharmaceutical workshops, and operating rooms.
Role in Epidemic Prevention: While ULPA filters offer superior performance, their high air resistance and cost make them unnecessary for ordinary civilian use. HEPA filters have achieved a “golden balance” in terms of cost-effectiveness and performance for public health and epidemic prevention.
II. How to Make HEPA/ULPA Air Filtration Technology Serve Public Health?
Integrating HEPA/ULPA technology into daily epidemic prevention is a crucial step in building an “indoor air safety net.”
1. Upgrade Central Air Conditioning Systems in Public Spaces: Airports, train stations, hospitals, schools, large shopping malls, and other densely populated places should prioritize installing or upgrading HEPA-grade filters in their return or supply air systems. This is equivalent to putting a giant “N95 mask” on the entire building, continuously purifying the circulating air and diluting and removing potential viral aerosols.
2. Widespread Use of Air Purifiers: In offices, classrooms, restaurant private rooms, and homes where it is impossible to modify central systems, air purifiers equipped with HEPA filters are a highly cost-effective option. When choosing, pay attention to the “clean air delivery rate” (CADR) value to ensure it matches the room size, and replace the filter regularly.
3. Creating a Near-Clean Local Environment: In specific high-risk areas, such as waiting areas in hospital fever clinics, nucleic acid sampling booths, and even the potential future “safe social rooms,” ULPA technology can be used to create a near-sterile local environment, providing additional protection for medical staff and vulnerable populations.
The recurring global pandemic serves as a stark reminder that the fight against viruses will be a protracted one. With diverse strategies for coexisting with viruses, our arsenal needs continuous enrichment. HEPA and ULPA filters, technologies that once quietly protected laboratories and factories, are now taking center stage, becoming a solid and reliable technological defense line for public health. Trenntech not only provides customized filtration products for industrial production but also aims to provide a powerful protective umbrella for every breath of indoor air we breathe.