Helping People Understand and Mitigate the Spread of Aerosol-Born Infections

A request in April 2020 to deploy a long-established optical technique to identify gas flows and the spread of aerosols in surgery opened up an entirely new avenue of research for Dr Kevin Nolan, whose primary interest is in studying the flow of liquids and gases – fluid dynamics. Initially the new research focused on identifying the potential spread of the COVID-19 virus in clinical procedures and therapy settings. More recently, still related to the spread of viral infection, it has expanded to encompass collaboration with manufacturers of air filtration equipment on how it can be used in various settings and has also led to his involvement in the development of new European standards for face coverings used in community settings.

“We’re talking about using IOT to measure air quality, using sensors almost like a real time indoor weather prediction”

Seeing is Believing

Dr Nolan was first approached by Professor Ronan Cahill, Professor of Surgery at the Mater Hospital, after he had seen on the internet work conducted by a university in Holland using the Schlieren optical technique to identify gas and aerosol leaks in surgery. Professor Cahill and his colleagues wanted to find ways in which the spread of an aerosol-born virus, such as COVID-19, in an operating theatre could be identified and then eliminated. They hoped this would enable surgeons to resume the range of procedures being severely restricted by the pandemic.

Keen to play his part in the emerging national emergency, Dr Nolan brought large and cumbersome Schlieren equipment, which had been built to help him in his research while at Bell Labs Ireland into how to keep computer and telecommunications equipment cool, and set it up in a theatre in the hospital. Schlieren makes small changes in the refractive index of air visible to the human eye and provides, for example, striking imagery of airflows – including the human breath. It therefore reveals the air currents containing liquid droplets, or aerosols.

The value of the technique as a means of demonstrating the potential spread of the virus in the human breath was immediately recognised by Professor Cahill and extensive use was made of the Schlieren technique to demonstrate to the public, via the media, what happens to the human breath when appropriate COVID-19 protocols, such as coughing into an elbow, are employed.

You can read the full case study here:?Helping People Understand and Mitigate the Spread of Aerosol-Born Infections