Testing and verification of Airora technology

The development, testing and verification of
Airora's patented biocidal technology

Introduction

Airora’s multi-million pound scientific, technical and engineering journey has taken over ten years and has involved several phases of prototype development. As the science is both relatively new and challenging we have required extensive independent testing to ensure both the safety and efficacy of the resulting product.

The journey has involved the expert and professional capabilities of a number of internationally renowned independent design, research and testing organisations, including:

The UK Building Research Establishment’s Internal Air Quality Team and Laboratories
PA Consulting
The UK Government’s Health Protection Agency (Public Health England)
The UK Government’s Health and Safety Laboratory
FDA Laboratory, Rochester, New York State
The University of Leeds
The University of York
The University of Ottawa

Underpinning the whole Airora journey has been the culture of generating sound evidence based on good science.

The chemistry behind Airora >

How it works

Airora's Hydroxyl Cascade

In outdoor air, natural chemical reactions continuously create a cascade of hydroxyl radicals, which are proven to kill (inactivate) all human pathogens. Hydroxyl radicals play a critical role in decontaminating the environment and are known as 'Nature's Detergent'. However, this atmospheric chemistry does not exist naturally indoors, where the risks of infection are therefore significantly higher.

Airora’s breakthrough technology recreates the effect of the natural chemistry of open air - creating a safe and natural hydroxyl radical cascade throughout an entire indoor space. Hydroxyls reach every corner of a space within seconds, ensuring continuous air and surface decontamination, everywhere. The University of Leeds, one of the few leading laboratories in the world which is able to measure hydroxyl radical density, has confirmed that our technology creates hydroxyls at a rate which aligns with typical ambient conditions at noon in the summertime.

Our technology is designed to operate 24/7, continously suppressing pathogens while people go about their daily lives.

Biocidal efficacy

The inactivation of pathogenic viruses and bacteria

Atmospheric hydroxyl radicals are proven to kill (inactivate) all human pathogens, be they bacteria or viruses, by a well understood process: In general terms, hydroxyls react with the lipids and proteins in their thin, delicate surface structures, causing lysing (breakdown).

Airora technology has been shown to continuously suppress high levels of pathogens, both in the air and on surfaces. Our extensive test data, from both the laboratory and the field, demonstrate Airora's rapid effectiveness in destroying bacteria and viruses, and also fungal spores. A summary of just some of our extensive laboratory test results is provided below.

Test Facility / Date	Test Type	Test Microbes	Test Method	Test Chamber Size	Results
HPA UK June 2006	Airborne	MS-2 Coliphage	Aerosolisation (high concentrations)	18m3	6 log (99.9999%) kill in less than 5 minutes
HPA UK Sept 2008	Airborne	1) Bacillus atrophaeus (gram +) “aerostable spore” 2) Staphylococcus epidermidis (gram -)	Aerosolisation (high concentrations)	18m3	1) 1 to 2 log (99%) kill in 60 minutes 2) 5 log (99.999%) kill in 2 minutes
HPA UK Nov 2007	Surfaces (steel & glass)	1) MRSA (low concentrations) 2) MRSA (high concentrations)	1) Tested over 1 & 4hrs. 2a) Tested at 24 hrs & 2b) Tested at 48hrs.	18m3	1) At 1 hour NO surviving MRSA on glass or steel. 2a) NO surviving MRSA on glass (greater than 6 log kill) & a 3 log kill on steel 2b) 4 log kill on steel

In summary, as tested:

all pathogens tested airborne, even MS-2 at high concentrations, are subject to a log 6 kill rate in minutes
surface borne MRSA on glass, even at high concentrations, is subject to a log 6 kill rate in 1 hour and on all types of surface to a 3 log kill rate in 16 hours

Note that Airora’s technology is ‘always on’ and is designed to constantly maintain maximum suppression of microbial contamination. The time taken to initially reach high kill rates should be read in that context.

Testing by Ottawa University

In addition to independent testing undertaken on our behalf, Ottawa University undertook testing on an Airora development prototype at the University of Ottawa on behalf of a third party. An example from the results is shown below.

Photographs of recovery plates from the 120 minute Reyniers slit sampler

The first stained photograph of the control plate (SE #1) shows the colony forming units (CFU) of Staphylococcus epidermidis recovered from the air of the aerosol chamber. The second photograph represents a preliminary examination (20 hours of incubation) of unstained bacteria of the test plate (T60- #1-1) representing the first evaluation of the development prototype (LED/35ppb O3).

Control Plate: Stability in Air (SE #1)

Test Plate: Device Test (#1-1)

It can be seen that the S. epidermidis has been reduced in numbers to undetectable in ~35-40 minutes (the challenge input – nebulizer fluid concentration of the SE#1 was 4.9Log10 and the #1-1 was 4.82Log10) these values show that the inoculums sprayed into the chamber are consistent and these plates can be compared to each other for the purposes of efficacy.

COVID-19 and MS-2 Coliphage

While it is not possible at this time (for safety reasons) to test our technology directly against the COVID-19 virus, we know that Airora's technology destroys ALL types of pathogenic viruses, including those in the coronavirus family (which includes the SARS-CoV-2 coronavirus that causes COVID-19), in the air and on surfaces.

This is demonstrated by the testing carried out by Public Health England's microbiologists at Porton Down using MS-2 Coliphage as a surrogate. In every test, our process quickly rendered MS2 Coliphage inactive in the air and on surfaces.

The microbiologists at Porton Down use MS2 Coliphage as a gold-standard surrogate for pathogens because it is exceedingly difficult to inactivate. If you can use a process to inactivate MS2 Coliphage then that process would be expected to inactivate all types of pathogenic virus and bacteria. Like all coronaviruses, MS2 is a positive sense single-stranded RNA virus and studies have shown that it is 7 to 10 times more resistant to denaturation (i.e. harder to inactivate) than a coronavirus.

Read an example of hydroxyls inactivating human coronaviruses >

Non-biocidal effects of hydroxyl radicals

Removing malodours

Malodour experiments are undertaken either by chemical analysis or by human noses. While there is extensive literature demonstrating the ability of hydroxyl radicals to react with, break down and remove malodours, HTL has also undertaken field tests to demonstrate the effects of Airora on malodours.

Airora has undertaken several human nose experiments, the most significant of which was in 2013. Using a professional consumer research firm, Airora took 12 groups of recruited consumers, both women and men, through a blindfold experience of an Airora device inside two different test houses. Each of the groups was then de-briefed which were captured on video (over 7hrs), with a two minute video summary (available under NDA) produced to illustrate the overwhelming reactions of the groups.

The language used by these consumer groups to express Airora's beneficial effect speaks for itself:

“outdoors” “in a spa” “on holiday by the sea” “feel energised” “motivated” “mountains” “forests”

Neutralising airborne allergens

Independent third party research relating to hydroxyl radicals and their effect on indoor allergens illustrates how hydroxyl radicals can prevent the onset of allergic reactions.

Pollens, Fungal Spores, Pet Dander

Hydroxyl radicals have been shown to reduce IgE-binding capacity in pollens, spores and pet dander through the degradation and modification of the tertiary structure and/or the induction of protein denaturation and/or aggregation. This allergen structure is no longer recognised by the body's immune system and therefore histamine and other chemical mediators are not released.

While the references below refer in their titles to cluster ions, the text makes it clear that the recorded effects are achieved by hydroxyl radicals which result from the chemical interactions between the cluster ions.

References:

Kawamoto S et al. Decrease in the Allergenicity of Japanese Cedar Pollen Allergen by Treatment with Positive and Negative Cluster Ions, International Archive of Allergy and Immunology, 2006, Vol.141, No. 4
Kazuo Nishikawa et al. Exposure to positively and negatively charged plasma cluster ions impairs IgE binding capacity of indoor cat and fungal allergens, World Allergy Organization Journal 2016

House Dust Mites

Hydroxyls instantly denature the allergen Der p1 and Der f1 found in house dust.

Hydroxyls oxidise their protein structures, for example protein backbone damage due primarily to a hydrogen atom abstraction at the alpha carbon. This process leads to backbone fragmentation.

Side-chain damage is another possible protein oxidation mechanism and can occur through hydrogen abstraction or oxygen addition. Both hydroxyl radical initiated oxidation mechanisms result in a modified allergen structure. This allergen structure is no longer recognised by the body's immune system and therefore histamine and other chemical mediators are not released.

References:

Garrison W M. Reaction mechanisms in the radiolysis of peptides, polypeptides, and proteins. Chem Rev 1987:381-398 -9920.
Singh J & Thornton J M. Atlas of Protein Side-Chain Interactions, Vols. I & II, 1992 IRL press, Oxford.

Removing VOCs and other pollutants / asthma triggers

It is well documented that the powerful oxidisation effect of hydroxyl radicals eliminates pollutants and common lung irritants such as ozone, volatile organic compounds (VOCs), formaldehyde and carbon monoxide.

BRE has undertaken extensive air quality testing of various Airora prototype devices. As part of these tests BRE attempted to qualify and quantify the test chamber air prior to, as well as during and after testing, in order to ascertain exactly the air emissions created by the Airora technology versus the background air.

These tests confirm that Airora's technology removes ozone, reduces VOC and carbon monoxide concentrations and does not lead to an unsafe level or accumulation of Formaldehyde, indeed formaldehyde is broken down and reduced over time.

References:

B. J. Finlayson-Pitts and J. N. Pitts, Jr., The Chemistry of the Upper and Lower Atmosphere, Academic Press, San Diego, 1999.
J. A. Logan, M. J. Prather, S. C. Wofsy, and M. B. McElroy, Atmospheric Chemistry: Response to Human Influence, Phil. Trans. Roy. Soc. (London) 290, 187 (1978).
C. J. Weschler and H. C. Shields, Production of the Hydroxyl Radical in Indoor Air, Environ. Sci. Tech. 30, 3250 (1996).

Please contact us via our contact page if you would like to review more extensive laboratory and real world biocidal and non-biocidal test data.

Safety

Hydroxyl Radicals

Hydroxyl radical generation has been approved by multiple regulators as safe air cleaning technology.

Air quality and trace compounds

Throughout the development of the technology the utmost concern has been to ensure the safety of the devices. To this end there has been extensive testing of the emissions starting with the earliest prototypes.

The Indoor Air Quality team at BRE undertook most of this work, with additional input from the University of Leeds and University of York.
At the outset a thorough study was carried out by BRE to determine international regulations and limits for various relevant compounds. From this the tightest limits were taken as the starting point for compliance. However, working with various third parties, who were interested in the technology, key limits were further tightened.

The testing at BRE was carried out in a specialist 18m3 chamber designed for air quality studies. This was chosen as it represented a small bedroom sized space reflecting the smallest room in a house where a consumer version of the device might be used. Testing in a small chamber like this represents a tougher challenge from an air quality point of view.

BRE and the University of York were, together, able to identify all trace compounds resulting from the use of our technology and were able to confirm that none were known to be hazardous.

Developmental timeline

2007
Extensive microbiological testing of prototype engines at the UK Government’s Health Protection Agency at Porton Down
Granted initial patent in GB followed by 60 jurisdictions

2008
Prototype designated T250 developed leading to radical steps in the understanding of the technology and device design

2010
T250 learning leads to concept design of ‘domestic’ prototype room scale devices, termed T35 (without a fan) and T50 (with a fan)

2011 - 2013
In-depth independent testing to confirm all aspects of safety and emissions and the associated regulatory requirements worldwide, with a target to reduce all emissions to < 1/10 of the acceptable regulatory limits

2013
Prototype T60 developed to embody and exceed all regulatory and other requirements
T60 subject to further extensive efficacy and safety testing

2014
Additional, new patents applied for and subsequently granted

2015 – 2016
Further developments and simplifications with a focus on Allergens and Asthma, leading to the development of the Airora Home

2017 - 2019
Final industrial design and testing of Airora Home
Development of a personal wearable device, Airora Personal

March 2020
Collaboration with PA Consulting to rapidly develop and bring to market the Airora Professional, a wall-mounted product designed for all types of commercial and public buildings, including Hospitals, Care Homes, Schools, Offices and Airports.