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Developing Airora’s Technology 

Part I - Solving the Open Air Factor (OAF) mystery

 

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A short peer reviewed history of how Airora cracked the mystery of the ‘Open Air Factor’ and revolutionised air and surface purification and sanitisation

The challenge of infection prevention

Preventing infections arising from contaminated air or surfaces remains one of  humankinds greatest challenges.

Cholera, bubonic plague, smallpox, and influenza have been some of the most brutal killers in human history. Smallpox alone has been estimated to have killed circa 500 million people over the last century[1]. More recently, in 2020, COVID-19 was declared a pandemic, and as of May 2023 the WHO reported that, worldwide, there have been more than 760 million confirmed cases and almost 7 million resultant deaths[2].

Few doubt that a new COVID-19 like pandemic will arise in the future. Indeed, the UK’s 2021 Integrated Review of Security[3] estimates that another novel pandemic remains a “realistic possibility” before 2030 as population growth, and the loss of wildlife habitats, are set to increase the risk of diseases jumping from animals to humans.

While COVID-19 has dominated recent headlines, The WHO estimates that more than 1.4 million patients worldwide in developed and developing countries are affected at any one time by health care-associated infections (HAIs) [4], that is an infection occurring in a patient during their stay in a health care facility which was not present or incubating at the time of admission. To put this into perspective, out of every 100 patients in acute-care hospitals, seven patients in high-income countries and 15 patients in lower income countries will acquire at least one HAI during their hospital stay. Sadly, on average, 1 in every 10 of those patients will die from their HAI.

That is the bad news, but the good news is that a new ‘hydroxyl cascade’ technology[5], promises to greatly reduce both HAIs and future pandemic related infections.

Fifteen years in the making, this breakthrough technology arises directly from our recent better understanding of the origins of outdoor air’s natural and powerful germicidal property, and how that effect can be replicated indoors.

Early history

The recognition that outdoor air has germicidal properties was widely exploited during the late 19th and early 20th centuries in the treatment of tuberculosis, where  patients underwent 'open-air therapy' to help them heal. It was further exploited by military surgeons during the First World War who used the same open-air technique to disinfect and heal severe wounds and by doctors to treat influenza patients during the 1918-19 pandemic[6].

There appears to have been little further interest in the germicidal properties of outdoor air following this period and during the 1950s chemical therapies  superseded ‘open air therapy’, and interest diminished.

During the 1960s and 1970s these germicidal properties were briefly re-visited by UK biodefence scientists at Porton Down[6] who conducted experiments proving that open air has a potent germicidal effect. However, not knowing the origin of the effect, they simply called it the ‘Open Air Factor’ or OAF. The Porton Down scientists demonstrated that OAF effect occurred outside but didn’t occur inside unless ventilation rates were very high indeed. From this they concluded that whatever the active agent was, it was clearly short lived. However, they ultimately failed to identify the active agent, as at that time no test technique was sensitive enough to identify and measure the OAF present in the air. 

When this research ended in the 1970s, interest in the OAF again fell away except amongst a small group of scientists, including the inventor of hydroxyl cascade technology, who were determined to unravel the mystery.

A solution is identified

In the years that followed, while hydroxyl radicals[1] were recognised as one possible  source of the germicidal effect, others contended that, given typical concentrations, their very short life and their creation at random locations, they were statistically unlikely to react with harmful viruses, bacteria and moulds in sufficient numbers to be the OAF germicide, but that other Reactive Oxygen Species (ROS)[2] might play a dominant role[6].

But by the turn of the 20th century, by persistently focussing on advances at the intersection of atmospheric chemistry, microbiology and aerobiology the inventor of hydroxyl cascade technology concluded that OAF wasn’t just hydroxyls in general and / or other ROS, but a particular subset of hydroxyl radicals that are created in a particular way, such that they became a powerful targeted germicide.

Hydroxyl radicals as a germicide

There are multiple sources of hydroxyls in outdoor air. The most common daytime source being a photochemical reaction which creates randomly dispersed hydroxyls. However, another significant source is the natural 24 hour outdoor reaction of ozone with aromatic essential oils emitted from plants[7]. The defining feature of this second source is that the underlying cascade reaction condenses, and has a strong propensity to occur on surfaces, including the surfaces of particles such as harmful viruses, bacteria and moulds[8]. It is hydroxyls created from this condensing reaction, at the very surface of viruses, bacteria and moulds, which target the hydroxyls and make them such a powerful germicide.

Fortunately, humans, animals, and plants have evolved over millennia to co-exist with hydroxyls and their reaction by-products[9]. Atmospheric hydroxyls cannot enter the blood stream or tissues within the body, because skin and mucosal membranes have evolved to provide a protective barrier.

It became clear that hydroxyls were not just a powerful outdoor germicide, but as they were not harmful for humans, they held considerable promise in infection prevention.

Over the last decade ‘air cleaners’ based on creating hydroxyl radicals by photocatalytic oxidation (as pioneered by NASA[10]) have become available. However, because the life of a hydroxyl radical is so short, their impact outside of the air cleaner is, whatever the claims made, strictly limited. In fact, these hydroxyl radical ‘air cleaners’ basically act as filters and share all the same physical limitations as other filters, principally that typically only 50% of the ever changing air in a room passes through the filter and is ‘cleaned’[11].

Development of the hydroxyl diffuser

The development challenge then was to create hydroxyl radicals throughout an indoor space, in a similar concentration to daylight outdoor levels, 24 hours a day, employing the aromatic essential oil cascade reaction which in turn preferentially targets harmful viruses and bacteria both in the air and on surfaces.

The inventor’s ‘Hydroxyl Diffuser’ does exactly that.

And the results are truly remarkable[12]:

  • Inactivating high concentration benchmark MS-2[3] airborne virus in less than 5 minutes according to Public Health England (Porton Down no less!).
  • Inactivating high concentration MRSA[4] on glass in 1 hour according to Public Health England. 
  • Inactivating high concentration airborne Staphylococcus epidermidis[5] bacteria in less than 2 minutes according to Public Health England. 
  • A simulated sneeze test with high concentration of bacteria saw a greater than 99.99% reduction in transmitted live bacteria after only 600mm according to BRE & IOM Stafford – the hydroxyl cascade is so powerful it creates a real time person to person infection shield!

And the benefits go well beyond virus, bacteria and mould inactivation. Hydroxyls also remove all odours, break down all VOCs and most other polluting gasses and damage the protein and tertiary structure of allergens so that they are no longer recognised by the body's immune system[9,13,14,15,16]. It is no surprise then that they have become known as ‘The Detergent of the Atmosphere’, because without them, life as we know it would not be possible on planet Earth.

Developing a safe and reliable technology

If it is so simple, how has it taken fifteen years for Hydroxyl Diffusers to become available?

Beyond creating the necessary reliable technology, the fundamental issues for the developers were to decide on and achieve a target hydroxyl concentration and to ensure that none of the emissions or by-products of the very complex underlying chemical reactions are harmful.

The concentration of hydroxyls in the lower atmosphere has been determined to generally lie between 0.5x106 per cm3 and 5x106 per cm3[17] depending on many factors, including time of day, humidity, temperature, season etc.[18]. In general, the concentration is lowest at the poles and highest at the equator.

The developers decided to fall well within this range by targeting output in the range of 1 to 3x106 per cm3 with a focus on 2x106 per cm3.  Performance within this range varies a little in terms of the time taken to inactivate pathogens, but the outcome over time is very similar.

Measuring hydroxyl concentration is however not easy, and so the developers turned to both Leeds University Atmospheric Chemistry Group and the UK’s National Health and Safety Laboratory to cross check measurements using different measurement techniques and then calibrate the Hydroxyl Diffuser technology.

Following detailed experimentation, the developers determined that the quantity of essential oil and ozone necessary to create the required hydroxyl concentration was fortunately very low, well below any cautionary, advisory or regulatory limits.

In fact, by employing the latest sensor technology, the Hydroxyl Diffuser monitors the air quality in real time and dynamically adjust its outputs to ensure that, where pre-existing background ozone levels are found to be too high, the resultant level falls to well within all advisory and regulatory limits.

In terms of by-products, the developers asked the world leading UK Building Research Establishment (BRE), Indoor Air Quality Group, to develop a test and evaluation regime to establish the product’s safety. That regime was focussed on two principal issues; are all by-products safe at the concentration created and do any by-products accumulate over time.

The test results were unambiguous:

  • None of the by-products, at the concentration created, either from the underlying process, nor from their reaction with any of the typical VOCs found indoors, are known to be harmful. This is the first time that such a comprehensive analysis has been carried out and involved not just the BRE but also two specialist Universities, Leeds and York, to identify each and every by-product.
  • None of the by-products accumulated over time, be they particulates or VOCs, indeed most tend to reduce over time.

As the Inventor told me, it was fifteen years well spent!

The Airora revolution

In conclusion, Hydroxyl Diffuser technology is both effective and safe and is set to revolutionise how we make those who are indoors safe from infection while simultaneously protecting those indoors with breathing problems from allergens and irritants.

 

You can find out all about Airora at airora.com

And contact us at support@airora.com

 

References

  1. Henderson, DA (2009) “Smallpox: The Death of a Disease – The Inside Story of Eradicating a Worldwide Killer”. Published by Prometheus Books.
  2. Search for “WHO Weekly epidemiological update on COVID-19” For the latest figures
  3. (2nd July 2021) “Global Britain in a Competitive Age: the Integrated Review of Security, Defence, Development and Foreign Policy”. UK Cabinet Office
  4. Global report on infection prevention and control (2022), World Health Organisation
  5. https://www.airora.com/imagined-by-nasa-delivered-by-airora.html 15/06/2023
  6. Hobday RA, Collignon P (Jun 2022) “An Old Defence Against New Infections: The Open-Air Factor and COVID-19”. Cureus PMID: 35875284
  7. Geyer A, Bächmann K et al. (Jan 2003) “Nighttime formation of peroxy and hydroxyl radicals during the BERLIOZ campaign: Observations and modelling studies”. Journal of Geophysical Research: Atmospheres
  8. Dark FA, Nash T (January 1970) “Comparative toxicity of various ozonized olefins to bacteria suspended in air” Journal of Hygiene 1970
  9. Martínez VR, Arañó LM et al. (April 2020) “Evidence of OH· radicals disinfecting indoor air and surfaces in a harmless for humans method”. International Journal of Engineering Research & Science
  10.  Perry JL, Frederick KR at al. (2011) “A Comparison of Photocatalytic Oxidation Reactor Performance for Spacecraft Cabin Trace Contaminant Control Applications”. American Institute of Aeronautics and Astronautics
  11. Novoselac A, Siegel JA (2009) “Impact of placement of portable air cleaning devices in multi zone residential environments”. Building and Environment 44 (2009) 2348–2356
  12. Summary results at https://www.airora.com/verification.html  14/06/2023
  13. Finlayson-Pitts BJ, Pitts, JN Jr. (1999) “The Chemistry of the Upper and Lower Atmosphere”. Academic Press, San Diego
  14. Garrison, Warren M. “Reaction mechanisms in the radiolysis of peptides, polypeptides, and proteins Chemical Reviews” 87 (2): 381–398
  15. Kawamoto S et al. (2006) “Decrease in the Allergenicity of Japanese Cedar Pollen Allergen by Treatment with Positive and Negative Cluster Ions”. International Archive of Allergy and Immunology Vol.141, No. 4
  16. Kazuo Nishikawa et al. (2016) “Exposure to positively and negatively charged plasma cluster ions impairs IgE binding capacity of indoor cat and fungal allergens”. World Allergy Organization Journal 2016
  17. Hewitt CN, Harrison RM (1985) “Tropospheric concentrations of the hydroxyl radical—a review”. Atmospheric Environment (1967) Volume 19, Issue 4, 1985, Pages 545-554
  18. NASA (December 2018) “Detergent-like Molecule Recycles Itself in Atmosphere” https://earthobservatory.nasa.gov/images/144358/detergent-like-molecule-recycles-itself-in-atmosphere 17/06/2023

Copyright Airora 2023 1 V 1.1

[1] Hydroxyl Radicals OH (commonly Hydroxyls) are the second most powerful oxidising agent after fluorine. Hydroxyls are abundant in outdoor air, with a typical concentration of 2x106 per cm3 during daylight hours. They are highly reactive with a life span in the atmosphere is typically less than one second.

[2] Reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (O2), including not just hydroxyl radicals but also peroxides, superoxide, singlet oxygen, and alpha-oxygen.

[3] By testing against MS2, the CDC confirms that hydroxyl radicals will inactivate pathogens in levels 1 – 4 of that Spaulding Classification, including all those in the coronavirus family (which includes the SARS-CoV-2 coronavirus that causes COVID-19). Level 5 Mycobacteria are basically no different in structure to other more susceptible bacteria and as Airora produces a never-ending supply of hydroxyls, even clumps of cells, thick layers and heavy cell walls are expected to eventually succumb. We are not aware of any pathogens which will not ultimately succumb to hydroxyl radical attack.

[4] Methicillin-resistant Staphylococcus aureus (MRSA) infection is caused by a type of Staphylococcus bacteria that's become resistant to many antibiotics.

[5] Multidrug-resistant Staphylococcus epidermidis (MDRSE) is responsible for difficult-to-treat infections in humans and hospital-acquired-infections.

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