The Future of Air Purification in Public & Commercial Buildings


The future of air purification in buildings occupied by the public is now in the spotlight. Implementing air purification systems in public areas such as airports, train stations and bus stations is likely to be the next step in our fight against Coronavirus.

Urban transport is an area of great concern in regard to the current pandemic, and research has stated that existing policies and practices within the design, construction and operation of these infrastructures may have negative implications when it comes to containing the transmission of airborne diseases.

Organisations such as ASHRAE have responded to our current situation by setting out professional guidelines, though these will be likely to change as the situation develops and more is learnt about COVID-19.

The increase in use of public transportation is closely tied into the development and expansion of today’s working population. People spend a significant amount of time either waiting for public transport or commuting and due to this, the exposure to airborne threats in these areas has continued to increase. Addressing the necessity of installing air purification systems in our enclosed public spaces – in areas such as bus stations, airports, and train stations – to successfully combat the current pandemic, seems therefore to be a sensible step to take.

Capital cities such as London face chronic overcrowding in transport hubs, especially during peak hours. The Department for Transport (DfT) stated in Spring 2011 that over-crowded services were between 47% and 66% over capacity both in the trains and in the stations. In turn, individuals were standing or sitting in extremely close proximity in poorly ventilated areas. This has obvious implications for the spreading of airborne diseases through both direct and indirect contact.

What Does The Future Hold For Air Purification Since The COVID-19 Pandemic?

The quality of our air has never been so important. The outbreak of Coronavirus has allowed us to reduce the amount of air pollution on one hand, thanks to a decrease in greenhouse gas emissions, however on the other hand we must strive to increase the quality of air indoors to protect our health and wellbeing.

Air filtration methods in ground transport structures will undoubtedly play a part in controlling the spread of Coronavirus. A paper in 2014 reviewed 14 events of confirmed airborne transmission that had occurred in the public transport sector, and while not being able to prove it due to the outbreaks not happening under monitored conditions, speculated that poor ventilation, proximity to infected individuals, and recirculated air were likely contributing factors.

A further case study completed in Nottingham has shown that use of public buses and trams posed a significant risk of acquiring acute respiratory infections.

A worrying example specific to Covid-19 of the danger posed in a closed environment was demonstrated on the Diamond Princess cruise ship in January 2020. Panic by various countries meant that the ship was quarantined for over a month and despite all passengers being confined to quarters, the infection spread to infect at least 712 of the 3711 passengers and crew.

We are still learning about the behaviour of airborne infections such as COVID-19 and the available information is still limited and tends to be focused on exposure during travel, as opposed to the dangers that exist while waiting to travel within transit hubs such as airports or train stations. However, the literature and research that has been done offers a frank insight into the risk factors of these environments, and it is not too much of an extrapolation to concur that poor ventilation in these types of buildings poses the same types of risks as those found within the similar confines of a train, plain, ship or bus. 

Monitoring Air Quality In Transportation Hubs And Concourses:

Since the outbreak of Coronavirus, it can be assumed that air quality in commercial and public spaces such as tube stations and bus concourses will likely be monitored by third-party health and sustainability certification companies in the near future.

Performance-based air quality results may be required as one-off tests, annually or through continuous testing. Recent advances in air technology have dramatically reduced the cost of air sensors which can provide readings on the air quality.

Monitoring the levels of air purity in public or commercial buildings will include the testing of CO2 amounts, total volatile organic compounds found, humidity levels, temperature and particulate matter.

It may transpire that air quality data for public or commercial buildings can be viewed remotely, therefore allowing for required intervention or troubleshooting should there be dangerous practices happening.

The PHI purification cell technology from RGF Environmental integrated in PureAir Air Purification & Odour Control System has validated test results showing up to 99+% reductions on enveloped or protein jacketed viruses similar to the Coronavirus. This has been reviewed by Associate Director of the National Agriculture Biosecurity Center and past Distinguished Professor Dr. James Marsden of Kansas State University, who supports that the evidence suggests “there is every reason to believe Airius PureAir PHI Technology would also be effective in reduction of COVID-19”.

PHI Cell technology has already been certified to reduce the levels of SARS virus by 72.92%  (a member of the Coronavirus family) and widely implemented by the Chinese Government in response to the 2002-2004 SARS outbreak. This sample was taken in a subway and highlights the effectiveness of this technology inside public buildings and transport infrastructures.

What Methods Can Be Used To Combat Coronavirus Through Air Purification?

Photohydroionisation technology, which uses ultraviolet C (UVC) light in air circulation systems, can be used to disinfect air supplies in indoor structures. It works by emitting a high intensity, broad-spectrum UV light projected on to a quad metallic target, producing ionised hydro-peroxides which capture and kill viruses.

Viruses, gases, bacteria and mould spores are all either killed or neutralised. The only remaining by-product from the reaction is Oxygen and Hydrogen, which are already naturally abundant in the air around us.

Hydroperoxides are otherwise known as ‘Mother Nature’s cleaning agent’ and are what make the air smell clean after a thunderstorm. They are naturally produced in our environment and are artificially created by the PHI Cell featured in the Airius PureAir System, in order to provide us with fresh, safe air.

Airius’ PureAir Air Purification and Odour Control System uses this PHI Cell advanced oxidisation technology to make sure indoor spaces have improved air quality, especially in the midst of the current Pandemic. For public spaces such as bus stations, airports and train stations which have many people passing through, controlling the air supply and making it as safe as possible is critical. The PureAir System works in buildings with ceilings up to 14 metres and more – perfect for spaces such as airports and train stations that often have higher ceilings.  

Humidity Control:

The amount of humidity in an indoor space has a substantial effect on the transmission of harmful pathogens. Where relative humidity is maintained, for example at around 40%, there tend to be fewer infections.

ASHRAE recommends that maintaining a humidity level of below 65% reduces the chance of mould growth, like wise holding the humidity between 40% and 60% may reduce the transmission of airborne bacteria. Scientists have found that dehydrated bacteria droplets remain floating in the atmosphere for longer, which subsequently increases the risk of transmission to humans.

Dehydrated virus cells are able to crystallise into a solid state which preserves them and enables them to last longer, therefore extending the time of possible transmission. When air humidity is kept constant at over 40%, the microbial droplets are able to retain moisture and therefore drop to the ground or a surface – which will then be more likely to be wiped away if you are following strict cleaning procedures.

The correct amount of moisture in the atmosphere allows for a more hostile environment for bacteria, as it can allow solutes within an aerosol to form dissolved salts – this inactivates the virus, mould or bacteria.

Due to the current Coronavirus pandemic, we must look at how air humidity is controlled in commercial and public buildings, especially during the colder months that will soon be upon us. Now we are fully aware of the consequences of airborne infections, it is crucial that humidity control is incorporated in an effective COVID-19 containment strategy.

The Airius PureAir Purifying Fan System can also help to manage and maintain ideal levels of humidity, by increasing or decreasing the levels of air movement in a space, as well as vastly improving the efficiency of air turnover.

Air Exchange Rate:

Fresh air and well-ventilated spaces are crucial for health and wellbeing, not only during this pandemic but also looking towards the future. A factor we must consider in this strategy is the air exchange rate of a building.

In buildings such as airports, fresh air is unlikely to reach the main parts of the building. But with the Airius PureAir system you could circulate fresh, safe, virus-free air throughout the entire building structure.

The fewer air changes a building or room has, the more likely it is that pollutants and viruses stay in the atmosphere. This is why is it important to maintain consistent levels of outdoor air ventilation and airflow circulation. In enclosed public spaces such as bus stations, train stations and airports, air treatment, filtration and purification methods can compound the issue relating to a lack of fresh outdoor air.

Because of the nature of these building’s design, public transportation buildings can greatly impact airborne disease transmission. The combination of the built environment alongside multiple individuals passing through these areas has been proven to result in higher transmission of viruses.

Particularly relevant to this case is the increase in international travel. Airports have the potential to act as hubs for the global spread of airborne diseases, for example SARS, H1N1 and Coronavirus. They play a critical role in the operation of controlling the nature of epidemics and pandemics – as their design and very nature make them a high-risk infrastructure to a bioterror attack.

Ventilation systems that achieve 100% outdoor air with zero circulation are important for preserving the wellbeing of the people that use these spaces. Higher air exchange rates greatly assist in diluting potentially contaminated air, as well as benefitting inhabitants by improving cognitive function.

The optimal rate of air exchange rate in healthcare environments is around 20 air changes per hour. Although commercial and public buildings do not require quite this level, since the rapid changes in protocol from COVID-19, it is recommended that solutions are correctly implemented to make sure air is purified as much as possible.

ASHRAE have recommended the following strategies for increased air exchange:

  • Leave HVAC systems on for a set time after occupants leave, for example after workers have left the office or shops have shut. This allows for a final flush out of contaminated air

  • Temporarily disable demand control ventilation and open the outdoor air dampers to 100% capacity when possible to maintain appropriate humidity and temperature controls.

The Airius PureAir System has been proven to significantly improve the quality of indoor air, airflow circulation and comfort and could be implemented in public indoor spaces to reduce the spread of viruses, bacteria, gases and volatile organic compounds. It also eliminates mould and odours, whilst the active cleaning agents provide indoor spaces with fresh, clean air.

Talk To Airius About The Future Of Air Purification In Public Buildings And Commercial Properties

If you would like to find out more about the Airius PureAir Air Purification, Circulation and Odour Control System for use in your building, please contact us and we’ll be happy to provide you with a No Obligation Quotation for your application.

The PureAir System has already been installed in a wide variety of applications and is perfectly suited for installation into public spaces such as train stations, airports, bus stations and other public transport concourses.  Small, compact and extremely versatile, we have developed Air Purification Solutions for both new builds, as well as all types of retrofits and even Protected Heritage Buildings with Airius Systems having already been installed in numerous Grade I, II* and II listed buildings.

Feel free to get in touch with us for more information by calling on 01202 554 200 or via email at