In recent weeks there has been increasing public discussion about airborne transmission of the COVID-19 causing SARS-C oV-2 coronavirus. In an open letter published on 6 July 2020, 239 scientists from across the globe urged WHO to affirm the airborne transmission route and to address the issue in guidance. WHO responded to this letter by acknowledging “emerging evidence” of airborne transmission. Better Indoors were among the first to write to the UK authorities about the significance of airborne transmission and we are pleased that our expert views are at last being recognised.
But, what does “airborne” really mean? The coronavirus is spread through tiny water droplets that contain the virus that are emitted when people sneeze, cough, talk and even just breathe. The size of these droplets ranges from visible particles that fall out of the air under gravity onto surfaces and floors to invisible particles so small they remain suspended in the air. It is these tiny particles, known as aerosols, that greatly increase the transmission risk because they can spread over long distances carried by internal airflows and can be inhaled by people who are a long distance away from the source. Indeed, research has shown that infectious aerosols can remain in the air for up to 16 hours and can maintain infectivity for longer periods. We believe this is one of two main reasons why this virus spread so far and so quickly and has become a global pandemic. The other being people are highly contagious without showing any symptoms – termed asymptomatic.
What is the option to minimize the aerosol transmission of the virus?
There is a high risk of transmission in any busy household or commercial space. An infected person will release the virus via aerosols inside these spaces which will likely be inhaled by another person somewhere inside the space. Crowded spaces however cannot stay locked down permanently but there needs to be more effective mitigation than simply wearing masks, social distancing, wiping down surfaces and limiting numbers.
At Better Indoors we have been advocating since this emergency began that every building must be served with effective ventilation combined with a process of active air purification. In the UK, most buildings are built to minimum ventilation standards which means they predominantly rely on natural background ventilation, or opening windows. This method is often leads to problems of indoor air quality especially during the colder months and would need to be improved upon in order to create robust conditions to prevent virus transmission. Ventilation however does not physically remove infectious aerosols, it just moves them around and/or expels them from the property. Active air purification offers the capability to physically destroy airborne virus and other organics such as bacteria, odours, mould spores, VOCs and house dust. Active differs from passive filtration/PCO type systems which must force all the air in a space through a unit to treat it which never guarantees all the air in a space is treated because it treats all the air and surfaces in a space simultaneously and continuously. In short, an indoor space that has effective ventilation and active air purification offers the most effective defence against airborne transmission of COVID-19.
Please read our blog: Air Sanitation System To Fight Against Second Waves of COVID 19 which shares some great insights about the second wave of coronavirus, what would be its impacts and how you can reduce its risk.