||HEPA Filters -
An acronym for High Efficiency Particulate Air filters, a HEPA filter is
one of the most effective and efficient air filtration technologies
employed today in the air purification industry.
Any "true" HEPA filter has passed a stringent test developed by the
ASHRAE, the American Society of Heating, Refrigerating and Air
Conditioning Engineers, to ensure the filter is capable of capturing at
least 99.97% of airborne particles as small as 0.3 µm (microns). A
micron is one millionth of a meter, or 1/25,400 of an inch.
|To give you a sense of how truly powerful these filters
are, imagine just one hair on your head. A single human hair can
measure over 100 µm wide, while a human red blood cell clocks in with a
diameter of 7 µm. A certified HEPA filter traps particles as tiny as 0.3 µm, protecting against a wide
range of microscopic air pollutants like dust, pollen, mold, and
bacteria that commonly enrage asthma and allergy symptoms and often
bread diseases and infections.
Originally developed by the US Atomic Energy Commission in the 1940s,
HEPA filters were first used during the Manhattan Project to protect
researchers from harmful radioactive particulate contaminants. These
first filters were made from blue asbestos and esparto grass, and were
lauded for their excellent dust storage, resistance to plugging from
oil-type screening smokes and uncannily high particle retention
capabilities. After World War II, HEPA filtration technology was
declassified by the US government and began its emergence into the
commercial and residential air filtration fields. At this time HEPA was
commercialized and became a registered trademark, but it also quickly
evolved into a generic term referring to any highly efficient air
HEPA filters have come a long way in the last 50 years. Today they are
composed of a mat of randomly arranged fine glass impregnated
cellulose fibers, usually pleated and folded over itself many times to
increase the filter's surface area and thus its efficiency. While the
air space between these randomly woven fibers may seem non-existent to
our naked eye, it is infect much larger than 0.3 µm. But, unlike common
filters that can only catch particles as small as the filter's smallest
opening, a HEPA filter employs the filtration mechanisms Interception,
Impaction and Diffusion to trap far smaller particles against the
filter's cellulose fibers. What you're left with is beautifully clean
air free of the invisible contaminants that plague households worldwide.
Commonly found in medical and surgical facilities, tuberculosis wards,
NASA clean rooms and microcircuitry laboratories, HEPA filters are
relied upon wherever the highest degree of air filtration is necessary.
Here at PureAirProducts.com we offer a wide range of whole house, room
and portable air purifiers that utilize true HEPA filters. Often working
in conjunction with other proven air purification methods, i.e.
Activated Carbon filters, Electro-Static filters, Ultraviolet Germicidal
Irradiation and Photocatalytic Oxidation, these purifiers provide
outstanding air filtration for homes of varying sizes and with multiple
indoor air concerns.
Check out these high rated HEPA air purifiers available now at
And for more information on HEPA filters and air purifiers in general,
be sure to visit the EPA's website on Indoor Air Quality at