Shopping for a home air purifier, a whole house air filter for the furnace room, or a new vacuum cleaner just wouldn’t be the same without the dozens of products that pride themselves on their top quality HEPA filters. But what is a HEPA filter? Read on for the facts and the history of HEPA air filters.
What Is HEPA?
HEPA stands for “High Efficiency Particulate Air.” HEPA is not a brand; it is a type of air filtration system that is said to remove at least 99.97% of the most difficult size of airborne particles to filter, particles of 0.3 microns or micrometres in diameter (0.3 millionths of a metre).
Particles of this size are considered the most difficult to filter, and the HEPA filter is even more effective at filtering larger and smaller particles. This makes the HEPA filter ideal for capturing things like dust, dust mites, mold spores, cigarette smoke, paint fumes, plaster dust, pet dander and even disease-causing microbes like viruses and bacteria.
How the HEPA Filter Works
HEPA filters rely on mats of randomly arranged fibers that intercept and trap particles. Unlike a conventional membrane filter, a HEPA filter does not catch particles that are larger than the gaps between its fibers. Instead, it relies on the movement of air through the filter, which forces particles to pass near or collide with a fiber and become caught.
History of the HEPA Filter
The first HEPA filter was developed in the 1940’s, during World War II by the USA Atomic Energy Commission, and used by the Manhattan Project to filter radioactive particulates out of the air and prevent contamination. Eventually, this technology was declassified, and in the 1950’s HEPA was trademarked and introduced commercially. The name HEPA has since been applied to any high efficiency air filter that passes the requirements of the United States Department of Energy.