Microbicidal ultraviolet lamps are being touted as a potential solution to the problem of indoor airborne transmission of respiratory infections and could be used to “supplement ventilation” in crowded spaces, it is being argued.

Respiratory physician and academic Professor Guy Marks is the co-author of a new paper calling for the adoption of germicidal UV radiation that kills or deactivates pathogens.

While the technology is almost 100 years old – it was first successfully used in classrooms in the United States in the 1930s to reduce the risk of airborne spread of measles – it has been relatively overlooked during the present pandemic.

But there are numerous benefits including low cost and low maintenance, argue Professor Marks and his co-authors in an MJA perspective (link here) published on Monday.

The article, co-authored by Queensland University of Technology physicist Distinguished Professor Lidia Morawska and University of Melbourne head of mechanical engineering Professor Jason Monty, urges major reforms to improve indoor air quality.

A major part of this means creating enforceable standards on indoor air quality, which was currently a “regulatory no man’s land”, they wrote.

Ideas include distributing CO2 monitors, which could be used as a proxy for ventilation, albeit with limitations.

However, even well ventilated spaces could become risky with large crowds or highly infectious pathogens such as SARS-CoV-2, and this is when germicidal UV radiation could be particularly useful, the authors say.

“If utilised in shared spaces, it could be doing to air what is done to water — every drop of water we drink is disinfected,” they write.

Purported benefits of the existing technology (UV‐C 254 nm) included low cost and energy usage, while lamps also do not generate new pollutants in the air.

Unlike many portable air cleaners, UV germicidal devices are also completely silent. And they are already covered by international and Australian standards as well as workplace safety standards, the authors wrote.

“Its extension to far UV radiation (222 nm), which does not penetrate the skin, opens greater opportunities for use,” they add.

“The technology is there, it is proven, but we need a social licence to use it.”

The authors say the paradigm shift in ‘clean air’ thinking needed to tackle airborne transmission of respiratory infections is comparable to the ‘clean water’ transformation of sanitation infrastructure that was implemented in the 19th century triggered by cholera outbreaks.

“All buildings, public and private, will require modernisation, which will take time, but it is not a case of building from nothing,” they conclude.

“We must act now, starting with setting appropriate indoor air quality standards.”