Health authorities around the world agree that COVID-19 is primarily spread through airborne transmission and this is supported by a wide range of studies that have examined the virus since it first emerged.
The availability of clean, uncontaminated air is therefore crucial in preventing the transmission of the virus and protecting people from infection in a wide range of environments.
This can be provided through reliable ventilation to a source of clean, uncontaminated air and/or through UV-C air disinfection systems to prevent viral loads from building-up within an interior environment.
Our UV-C antiviral air treatment solutions were successfully deployed during the first SARS crisis of 2003 (SARS-CoV-1). Similarly to COVID-19 (SARS-CoV-2), SARS is an airborne virus which can quickly spread in indoor settings. Our solutions were effectively deployed in hospitals to mitigate transmission risk in highest risk settings and they can now also be used to prevent transmission of COVID-19, which is more easily destroyed using UV-C than its SARS-CoV-1 predecessor.
Like other coronaviruses, COVID-19 will mutate as it spreads through a population and many in the medical and scientific community expect COVID-19 to be a long term problem around the world, even with the availability of vaccines. It is therefore important that steps are taken to protect people and environments if we are to live with this ongoing danger.
As well as good management processes and personal protective equipment, one can deploy engineered COVID mitigation solutions through infection intervention.
Airborne bio-hazard infection prevention
To reduce the transmission of COVID-19 in indoor environments, we recommend the following:
Ventilation systems must draw as much clean outdoor air into interior environments as possible. Take measures to filter adequately, especially in built-up areas or those with an API of 50 or more.
HVAC systems should utilise the best quality filters that are practicable, given the constraints on plant capability, capacity and maintaining airflow velocity. Ideally, deploy Germicidal UV-C, MERV14 - HEPA for coronavirus.
Engineered Germicidal UV-C devices should be deployed in the duct, near the filter and coils, to suit the duct size, airflow velocity(contact time), temperature range, humidity, target microbe and target inactivation level (i.e. clean, disinfected or sterilised air).
Systems should maximize the number of air changes in each room per hour. We recommend a risk-assessed approach to suit use, ideally achieving 10 air changes per hour or more but not less than 15 litres/person/second occupancy. For new buildings, this can be specified, but existing buildings or systems may require major refit or upgrade. Air distribution is just as important as the design flow rate.
If 10+ air changes per hour cannot be achieved, if air distribution is inadequate or if dead spots exist, then existing systems should be supplemented with air mixing, with fans carefully located, and fan-assisted germicidal UV upper room emitters should also be introduced for local intervention.
In more complicated or higher risk environments, using CFD (computational fluid dynamics) modelling to predict airflow, distribution, dead zones and aerosol generation mapping to engineer targeted UV-C interventions whilst maintaining safety.
Deploy carbon dioxide (CO₂) monitors or testing as a surrogate measure in case of inadequate ventilation to reduce long-range transmission risk in shared room air. This is important as historical data from tuberculosis outbreaks has proven that CO₂ concentrations above 1000 PPM significantly increase the risk of becoming infected through airborne transmission. Tuberculosis is a deadly airborne pathogen that is transmitted in a similar way to COVID-19. Studies have shown that improving the building ventilation to achieve a CO₂ concentration of 600 PPM significantly reduces the viral transmission of TB. Alongside the use of germicidal UV-C air disinfection, these engineered solutions may have a game-changing effect in suppressing the COVID-19 pandemic.
How does UV-C work?
Germicidal UV-C is a particular type of invisible short-wavelength ultraviolet light (254nm) which is naturally produced by the sun, although it does not normally enter the Earth’s atmosphere. For more than a century, UV-C generated through properly engineered emitters has been proven to kill or inactivate microorganisms including viruses by destroying nucleic acids and disrupting their DNA and RNA.
The effectiveness of UV-C has been demonstrated against highly infectious airborne diseases including tuberculosis, measles, SARS and COVID-19, which can be destroyed within milliseconds through exposure to UV-C.
Why is ventilation important?
Good ventilation reduces the concentration of viruses in the air and therefore reduces the risks from airborne transmission. Airborne viruses can be contracted through inhaling small particles (aerosols) in the air after someone with the virus has occupied an enclosed area.
Unfortunately, few indoor environments have been designed with consideration for the risk of a highly infectious viral pathogen and so reliable and safe ventilation systems which are suitable for infection prevention is not always achievable using existing systems.
Cold weather also aids the transmission of airborne viruses such as COVID-19 and so attempts to ensure ventilation may not necessarily have the desired effect.
There are also important weaknesses which must be considered and opportunities for improvement in many systems.
Air filters are used in modern ventilation systems or in portable, so called, “air-purifiers” or “air purification systems”. Filters help to intercept small particles such as pollutants, pollen, dust and some microorganisms, but even high quality filters will not intercept all viruses, including COVID-19 sufficiently.
However, if filters are supplemented with competently engineered UV-C filaments within the ductwork, these systems can be very effective intervention to mitigate infection risk from all airborne viral hazards.
Here are some examples of filters and pore sizes of the filter holes:
Heating, Ventilation & Air Conditioning (HVAC) systems which re-circulate air in buildings, in full or in part, are the most common form of ducted systems in the world.
However, studies have shown that these carry a risk of increasing viral transmission rather than decreasing it. This is particularly the case in confined spaces because the potentially infected human exhaled aerosol from occupants is inevitably collected by the ventilation extraction system. The air currents then carry this aerosol through the ducts, where it then passes over heater/cooling coils before being re-spread in the room and indeed, other rooms, spreading microbes even more rapidly.
The viral load generated by occupants of an environment builds over time, unless it can be diluted by introducing more outside air, and HVAC systems can give a false impression of air purity while also accelerating the spread of a virus.
A considerable draw-back of all mechanical ventilation (recirculated or fresh air) systems is that a biofilm can gradually build on the coils and filters over time, significantly reducing their energy efficiency. Caused by microbial growth, biofilm can be prevented by irradiating the coils using UV-C lamps which can also inactivate airborne microbial hazards within the system, disinfecting airborne contaminants that are not caught by the pre-filter through exposure and eliminating surface growth.
A recent study by McKinsey & Co confirms that upgrading HVAC systems by incorporating higher-grade filters can be very expensive and unfeasible in some situations. What’s more, even the very best medical grade HEPA filter will not eliminate the hazard concerns of viral airborne transmission.
Due to the shortcomings of HVAC systems, UV-C is often used on spacecraft and submarines along with high quality filtration.
Existing HVAC systems can be upgraded to improve viral-security using UV-C but this cannot be achieved through upgrading filtration alone.
Medical Grade Air Purifiers (HEPA+UV-C)
The majority of so called, “air purifier” devices are basic air processors which only remove larger particulate matter from the air but not small bacteria and viruses, such as SARS-CoV-2 which causes Covid-19.
Our purifiers are the highest efficacy level of medical grade quality. These portable air purifier devices have been proven to be extremely effective at stopping Covid-19 infection in hospitals in Northern Europe and now, we have a sole distribution agreement to supply these potent infection intervention products in the UK.
PP-L’s air purifiers combine 5 sets of filters and uniquely, combine a HEPA 13 filter, which captures all airborne particles down to a certified size of 0.3 microns, plus a UV-C disinfection lamp and then, yet another but even finer HEPA 14 filter, which will trap microbes down to the tiny 0.1 microns level of filtration. The double medical grade HEPA with virus destroying UV technology means that these PP-L devices are arguably, the best air purifiers now available, anywhere.
Our portable air purification products are ideal for inside clinical and high-care spaces such as hospitals, GP surgeries, dental clinics and consulting rooms, as well as conventional spaces such as offices, meeting rooms, cafes, pubs, restaurants, changing areas, lobbies, etc. The PP-L devices will also purify air at an industrial rate such is the quality of the Scandinavian Engineering and a single device is capable of rapidly purifying the air in spaces up to 300 m2.
All CE Marked, ISO 9001 and ISO 14001, as all our products.
In terms of maintenance costs, these devices can safely operate for up to 20,000 hours (c.2 years) constantly-24/7 between HEPA & UV lamp changes which gives these devices the lowest level of whole-life costs compared to the nearest rivals which require filter changes every 6 months.
For larger rooms and whole buildings, we can go to an industrial scale of air purification with our fixed fan assisted upper room UV-C devices and HVAC engineered COVID-19-Secure air disinfection solutions.
UV-C Air Infection Intervention Technologies
Our proven UV-C biotech air treatment solutions were utilised to great success during the first SARS crisis in 2003. The current Coronavirus, SARS-CoV-2 is much easier to destroy with UV irradiation than its SARS-CoV-1 predecessor, whether in the air or on surfaces.
PP-L is able to provide bespoke engineered solutions with UV-C for whole buildings and at an industrial scale for spaces both with and without HVAC ducted systems, re-circulated air systems, or in spaces with poor ventilation. We also offer portable Air Purifier Products that combine the use of HEPA filters and UV-C that are specified for smaller spaces.
Our UV-C technology and UV-HEPA Purification products are very economical to buy and maintain because the lights themselves are relatively inexpensive and they are highly efficient at inactivating microbes for around 12,000 hours at best efficacy. When our light fittings are changed, there is a very low risk to the person changing them or filters behind them, as all microbes within its vicinity would have been inactivated by the light prior to it being changed.
|Air Purifiers||Our UV-C & Air Technology Products|
|Able to remove microbes of any size||X||✓|
|Low Risk to Change Filter||X||✓|
|Does the system remain effective for over a year||X||✓|
|Are they non-chemical and cheap to run||✓||✓|
|Can they disinfect against all virus’s in the air||X||✓|
How does UV-C destroy viruses and microbes?
PP-L’s UV-C products have been developed over 80 years at our Swiss manufacturing facility. With over 130 global patents built up since 1939, the products rely on the trusted blend of gasses in quartz glass tubes to produce the most effective antiviral UV-C light on the market.
UV-C light is a non-ionising form of radiation with a wavelength between 200nm-280nm, our products produce a wavelength of 254nm – the optimum wavelength for destroying microorganisms – and our products are also non-ozone producing, unlike some UV products.
UV-C light is also known as germicidal ultraviolet irradiative light (UVGI) as it destroys the DNA and RNA of microbes by breaking bonds between the thymine and adenine pair and bonding two adjacent thymine nucleotides together. This instantaneous inactivation process stops the exposed microbes from undergoing mitosis and causing harm whether they be in the air, on surfaces or in liquids.
The inactivation solution depends on the medium, environment, hazard source, presence of people or animals, temperature, humidity, bio-load (viral load), exposure time and target microbe that one seeks to eradicate.
Our UV-C antiviral air treatment solutions were rapidly and successfully deployed during the first SARS crisis in 2003 for hospitals, environments which are amongst the highest infection risk settings. While it has similarities to SARS, COVID-19 is even easier to destroy with UV-C, whether in the air or on surfaces, making UV-C a highly effective tool to prevent transmission and protect health.
What evidence is there that UV-C works?
UV-C has been used for more than a hundred years to treat and prevent contagious diseases and there is a wealth of evidence going back decades to demonstrate UV-C efficacy in the inactivation and destruction of all known microorganisms. These include highly contagious airborne viruses including COVID-19.
Our UV-C products have been proven to inactivate over 35,000 different microbes. The irradiation energy required to inactivate these microbes and other relevant biohazard information are stored in our database, which is one of the largest private databases of its kind in the world. We have our own laboratories and partner with other scientific institutions.
We also possess approximately 4,500 peer reviewed scientific papers which support these conclusions and several studies since the start of the COVID-19 pandemic have demonstrated that UV-C is highly effective in quickly inactivating SARS-CoV-2 (COVID-19) to prevent its transmission.
Studies have shown that COVID-19 is capable of remaining airborne for up to 16 hours, travelling tens of metres through the air in an indoor environment, particularly when the air is cold. Studies have also shown that inhalation is the most common means of transmission, with 57% of people being infected in this way, compared to 8% who are infected through contact with surfaces.
Professor Donald Milton, an aerobiology expert from the University of Maryland, was instrumental in the World Health Organisation (WHO) announcement in July 2020 that COVID-19 can be transmitted via the air. He underlines the importance of swift action to prevent airborne transmission in indoor environments: “We need to subsidise bars and restaurants to stay closed. We need to increase ventilation where we can and start making as widespread as possible use of air sanitation with upper-room germicidal UV and maybe far UV in those places that must be open, like elementary schools. We need to stagger hours of starting work and keep density on public transport low, or open windows. And we need to wear masks”.
The science behind UV-C is well documented and widely acknowledged around the world. Please contact us for links to some of the hundreds of scientific papers that we have and continue to assemble on the efficacy of UV-C as a highly effective infection intervention against COVID-19. These include papers on the human aerosol transmission routes, and papers on various forms of ventilation and their strengths and weaknesses.
For more information on how PP-L Biosafety can help your organisation to improve air security to prevent the transmission of germs and viruses, please contact our team.