What are HEPA Filters and How They Work in Air Purifiers.
High-Efficiency Particulate Air (HEPA) filters are among the most trusted air filtration technologies used in residential, commercial, and industrial air purification systems. Originally developed during World War II to trap radioactive particles, HEPA technology is now widely used in hospitals, cleanrooms, factories, and modern HVAC systems.
According to the U.S. Environmental Protection Agency, a true HEPA filter must capture at least 99.97% of airborne particles as small as 0.3 microns. These particles include dust, pollen, mold spores, bacteria, and even certain airborne viruses.
How HEPA Filters Work
HEPA filters do not work like simple strainers. Instead, they use three advanced filtration mechanisms:
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Interception – Particles following airflow stick to fibers.
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Impaction – Larger particles collide directly with fibers.
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Diffusion – Extremely small particles move randomly and get trapped.
This combination makes HEPA filtration highly effective in removing PM2.5 pollutants — a major concern in Indian cities.
Applications in HVAC Systems
In commercial HVAC systems, HEPA filters improve indoor air quality (IAQ), especially in:
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Clean rooms
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Pharmaceutical units
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Hospitals
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Electronics manufacturing
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Food processing plants
Organizations like ASHRAE recommend proper filtration standards to maintain optimal indoor air quality in commercial buildings.
For industrial facilities, integrating HEPA filtration with a well-designed HVAC system ensures compliance with environmental and occupational safety standards.
