Origins and Applications of HEPA Filters
HEPA filters were originally developed during the Second World War to prevent the spread of airborne radioactive contaminants as part of the Manhattan Project. Today, they’re utilized in a wide range of applications where clean air is required—from air purifiers and HVAC systems in homes and offices, to clean rooms in industries like pharmaceuticals and aerospace, and medical settings like operating rooms and isolation wards.
How Does a HEPA Filter Work?
The HEPA filter works by trapping particles in a complex web of fibres. This web, typically composed of fibreglass with diameters between 0.5 and 2.0 micrometres, forms a dense network of gaps and holes. Particles are captured in the HEPA filter through a combination of three mechanisms: interception, impaction, and diffusion.
Limitations of HEPA Filters
While HEPA filters are highly efficient at removing particulate contaminants from the air, they do not remove gaseous pollutants such as volatile organic compounds (VOCs) or radon. Additionally, they do not kill organisms like bacteria or viruses; while many of these organisms can be captured due to their size, they may remain alive once trapped.
Therefore, in some cases, HEPA filters may be used in conjunction with other air cleaning systems, like activated carbon filters for removing gases, or ultraviolet (UV) light systems for killing microorganisms.
HEPA Filters and Air Quality
In the context of your article on ventilation in a windowless room, a HEPA filter could be part of an air purifier system used to help circulate air and reduce airborne contaminants.
It’s always advised to ensure any HEPA filter system used is properly maintained, including regular filter changes as per the manufacturer’s guidelines, to ensure the system’s effectiveness.
