Data is one thing, interpretation another
Failure to comprehensively assess and contextualise all relevant data can lead to biased policy decisions and must be challenged
The widespread adoption of Far-UVC is contingent on a comprehensive appreciation of risks, benefits and context: incomplete or misleading information must be challenged. Two papers recently published in the John Hopkins University Journal Health Security could potentially distort perceptions of the risks of ozone from Far-UVC. Both papers conclude that risks from ozone are such that Far-UVC cannot currently be recommended for widespread adoption. Make no mistake; if this advice is followed, people will suffer and die needlessly as a consequence.
I believe the data does not support these conclusions, and I am so concerned that I am submitting a formal complaint to the publishers regarding these papers, requesting critical amendments that fundamentally alter the conclusions. This isn’t something I particularly enjoy doing, but this post explains why I believe it is necessary.
The coincidence of the Covid-19 pandemic with the explosion of open access scientific publishing has led to a huge interest in the science within the online Covid Cautious community. Unfortunately, I have seen many cases where published articles lack sufficient scientific rigour, and where the peer review process has, in my view, failed. This has often resulted in low quality papers being promoted online by an uncritical community, which can have damaging long term consequences.
Two papers caught my eye last month, specifically the discussions on the issue of Far-UVC and the risks of ozone and resulting pollutants, such as secondary organic aerosols (SOA)
and
Paper 2) Breaking Down Silos: A Multidisciplinary Approach to Mitigate Indoor Airborne Pathogen Transmission
What struck me most forcibly was that neither group of authors chose to reference any of the several published papers based on realistic real-world scenario measurements of indoor ozone/SOA produced by Far-UVC, which have consistently shown that the use of Far-UVC at the minimum intensities required for disinfection, combined with basic ventilation rates, do not result in any significant increase in ozone levels that could be considered hazardous to human health. [For readers interest, I have provided some of these references below]. Instead, both papers 1 and 2 chose to focus their commentaries and references on sealed teflon chamber experiments and mathematical models derived from these, without discussing the limitations of such studies.
Teflon chamber experiments are conducted in a controlled, isolated and inert environment that is not representative of real-world conditions. They will inherently find elevated ozone levels caused by Far-UVC compared with those found in real world situations. Mathematical models derived from these can provide useful insight, but are highly dependent on the quality of the input data and the assumptions built into the construction of the models.
Both papers 1 and 2 extensively cited published research based on teflon chamber experiments and associated models. Only one real world study was cited in either case (paper 1): Influence of Germicidal UV (222 nm) Lamps on Ozone, Ultrafine Particles, and Volatile Organic Compounds in Indoor Office Spaces. However, this study inexplicably focused solely on how Far-UVC affects ozone/SOA levels in a series of office buildings when the HVAC systems were shut down, leaving the buildings running at unfeasibly low (and illegal) ventilation rates of 0.2 ach.
This is the equivalent of researching winter temperatures in a building when you turn off the heating. It gets cold! In the study scenario, the answer is to simply switch the HVAC system back on. Problem solved!
Even with virtually no ventilation, they found only modest increases in ozone with Far-UVC, still well below the equivalent rates found in teflon chamber experiments, and inconclusive results regarding the formation of secondary pollutants. Indeed, the referenced study authors state: “These discrepancies [lower ozone levels than teflon chamber studies] are attributed to the small volume of the test chambers, the higher O3 production rates caused by the increased reflectivity of the chamber materials compared to building materials, and the lower O3 decay rates caused by both limited surface deposition and gas-phase reactions”. In other words, they are saying that teflon chamber experiments are unrealistic.
With these caveats, this study further undermines the conclusions derived solely from teflon chamber studies, although the authors of paper 1 failed to highlight or discuss such a perplexing methodology within the referenced study, or to contextualise the findings of this and other teflon chamber studies as non-realistic under real world operational conditions.
The failure in papers 1 and 2 to cite several published papers showing no adverse ozone effects from Far-UVC under realistic real-world conditions in the references and associated commentaries are serious over-sights which should, in my opinion, have been picked up by the peer review process. I view these as glaring omissions which completely distort the conclusions of the papers. I believe the papers need to be substantially amended to include the full range of references on the subject of Far-UVC and ozone, with further substantive alterations to the text to correctly state current knowledge on this issue. I will also be questioning why the publishers peer review process failed so spectacularly on this point.
In public health policy, details matter. Such a distorted review of current science on the issue of Far-UVC and ozone could be construed as misinformation, although I’m sure the authors did not intend this. However, in my view these errors are serious, and if they serve to potentially slow down the wide-spread adoption of such an effective, life-saving technology, lives will be lost needlessly. The researchers, reviewers and publishers all have a responsibility to correct such errors.
Real world studies into Far-UVC and ozone:
Effects of germicidal far-UVC on ozone and particulate matter in a conference room
222 nm far-UVC light markedly reduces the level of infectious airborne virus in an occupied room