NanoMasks FAQS Why we test to .027 Microns

Why we test to .027 Microns

Filtration efficiency is the measurement of a filterís capacity to effectively remove particulates, such as virus and bacterium, from moisture or air over a specified period of time. It should be noted that the number of digits after the decimal point (i.e. .99 vs. .999) is a function of the test and not necessarily a reflection of filter performance. It should also be noted that it is common to challenge air filters at 0.3 microns during filtration efficiency testing on the premise that if water droplets, or other large particles, are removed from an air stream all pathogens are removed as well.

While it is obviously much easier to achieve a favorable result at 0.3 microns; it has been proven that relative efficiencies will diminish as the contaminates decrease in size (virus are much smaller than bacterium), when filters are subjected to higher volumes of airflow or higher quantities of particulate, and when filters are in use over a prolonged period of time. Efficiency is more meaningful then when stated in terms of percentage of efficiency and particulate size. To put this into perspective, the image to the left shows the relative differential between 0.3 microns and 0.027 microns (the challenge particulates size for 2H Technology testing) and the following chart demonstrates why testing below 0.3 microns in size is relevant
Species Size in Microns

Associated Diseases

Bacteriophage ØX174 0.025 to 0.027 diameter

Test virus used by Nelson Laboratories to test 2H Technologyô filtration efficiencies

Hepatitis Virus (HBV) 0.042 to 0.047 diameter Hepatitis B
Adenovirus 0.07 to 0.09 diameter Respiratory Infections
HIV 0.08 to 0.11 diameter

Acquired Immunodeficiency Syndrome

Filoviruses 0.08 diameter
0.79 to 0.97 length
Ebola Virus
Bunyaviridae 0.08 to 0.12 diameter Hanta Virus
Orthomyxoviridae 0.08 to 0.12 diameter Influenza A, B, and C

Coronaviridae (SARS-CoV)

0.10 to 0.12 diameter SARS

Varicella-Zoster Virus

0.11 to 0.12 diameter Herpes
Cytomegalovirus 0.12 to 0.20 diameter Pneumonia, Hepatitis, Retinitis, Encephalitis
Variola Virus 0.14 to 0.26 diameter
0.22 to 0.45 length
Small Pox
Serratia Marcescens 0.45 diameter

Extraintestinal Infections,
Nosocomial Infections

Pseudomonas Aeruginosa 0.50 to 1.0 diameter
1.5 to 4.0 length

Endocarditis, Pneumonia, Osteomyelitis, Nosocomial Infections, Meningitis, Septicemia

Staphylococcus Aureus 1.0 diameter

Pneumonia, Osteomyelitis,
Acute Endocartis
Meningitis, Toxic

Mycobacteriumtuberculosis 1.0 to 5.0 diameter Tuberculosis
Bacillus Anthracis 1.0 to 1.5 diameter
3.0 to 5.0 length
Anthrax Infection
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