Scientific Evidence

Safe and effective air purification proven by
over 15 years on the market and the most extensive safety and efficacy data in the industry.

Destruction of Airborne Pathogens


At the Aerosol Research and Engineering Laboratories (ARE Labs), a U.S. laboratory specializing in the study of aerosolized microorganisms, PYURE conducted an evaluation of the kill rate on several pathogens, including viruses, bacteria and mold. The MDU/Rx™ device demonstrated a kill rate of between 99.9% and 99.99% within an hour.

PYURE efficacy was evaluated on five biosecurity level one (BSL-1) microorganisms that are considered representative of a broader range of more pathogenic organisms:

  • Scientific Graphs
  • Select pathogen to view study results
  • MS2 - Reduction in Viable concentration vs. Time
  • PhiX174 - Reduction in Viable Concentration vs. Time
  • Staphylococcus epidermidi - Reduction in Viable Concentration vs. Time
  • E. herbicola - Reduction in Viable Concentration vs. Time
  • A. Niger - Reduction in Viable Concentration vs. Time

Two viruses were selected to evaluate performance against RNA and DNA based viruses:

• MS2 bacteriophage is a positive sense, single-stranded RNA virus that infects the bacterium Escherichia coli. MS2 is routinely used as a simulant for pathogenic RNA viruses such as SARS.

• Phi-X174 bacteriophage is a circular single stranded DNA based virus that infects the bacterium Escherichia coli. Phi-X174 is routinely used as a simulant for DNA viruses such as smallpox.

Two vegetative bacteria were selected as simulants for a broad range of pathogenic bacteria:

• Staphylococcus epidermidis, a Gram-positive bacterium and simulant for a range of medically significant pathogens such as Staphylococcus aureus (“staph” infections).

• Erwinia herbicola, renamed Pantoea agglomerans, is a Gram-negative bacterium commonly used as a simulant for Francisella tularensis and Yersinia pestis (bubonic plague).

One species of black mold

• Aspergillus niger was selected because it is a pernicious black mold that has been attributed to many respiratory problems for infants, the elderly and immunocompromised individuals. It is particularly difficult to kill in air and on surfaces.

Safety and Toxicology


Comparative Biosciences, Inc. in compliance with the US Food and Drug Administration GLP regulations (21 CFR Part 58), conducted a 13-week toxicology study on the effects of elevated PYURE output levels on a statistically significant population of rats. Rat exposure levels were 2 to 3 times higher than the maximum levels recommended by PYURE. The results showed no adverse effects on treated animals vs. control animals after continuous exposure for 13 weeks, neither at the gross or cellular level.

This toxicology study, along with the mechanism of action and pathogen destruction studies, were submitted to the FDA as part of the 510k registration and listing for the MDU/Rx™ unit. As part of the FDA submission, a review of NIH, CDC and other relevant government databases was conducted. The review did not reveal any data or evidence that natural natural or artificial hydroxyls are in any way toxic to humans, animals or plants.

Mechanism of Action


A study conducted at the Lovelace Respiratory and Research Institute (LRRI), in an ultra-clean environmental chamber demonstrated that:

• Hydroxyl production levels are similar to the hydroxyl concentrations produced by sunlight outdoors

• Hydroxyls react within 20-40 milliseconds with volatile organic compounds (VOC) and generate powerful organic oxidants stable enough to circulate throughout the treatment space and sanitize air and surfaces

• The reaction rate of hydroxyls with VOC is a million times faster than ozone

• A very small quantity of ozone is produced as a byproduct of hydroxyl production, but the concentrations produced stay well within safe limits for occupied spaces

These results were subsequently published in a peer reviewed scientific journal. (David R. Crosley, Connie J. Araps, Melanie Doyle-Eisele & Jacob D. McDonald (2017) Gas-phase photolytic production of hydroxyl radicals in an ultraviolet purifier for air and surfaces, Journal of the Air & Waste Management Association, 67:2, 231-240, DOI: 10.1080/10962247.2016.1229236).

A study of the chemistry resulting from hydroxyl decomposition of VOC was conducted at Columbia Analytical Group. The results showed that ambient VOC were rapidly decomposed and that the steady state amounts of intermediate organic decomposition products, including aldehydes, ketones and alcohols did not increase above ambient levels in the treated space. PYURE Technology decomposes the VOC initially present and then decomposes the VOC formed as oxidation by-products, leaving behind a low, steady state concentration of VOC like that found outdoors.