Citizens and Scientists Are Petitioning WHO About Airborne Transmission of Covid

How did it come to this?

Covid is Airborne

Covid is Airborne

"Citizens of the World" have started a petition on, demanding that the World Health Organization (WHO) "recognize the compelling scientific evidence that SARS-CoV-2 spreads by aerosol transmission ('airborne') and urge the WHO to immediately develop and initiate clear recommendations to enable people to protect themselves."

Most of the organizers and petitioners from around the world appear to be building scientists, some of whom have been regulars on Treehugger. Since late March we have been covering building scientists' assertations that the virus is an aerosol that can travel long distances, much like smoke from a cigarette, rather than droplets that fall to the ground within six feet. The WHO recently acknowledged the fact of aerosol transmission, as did the USA's Centers for Disease Control and Prevention. So why are all these people doing petitions?

How Did It Come To This?

The petitioners note that the WHO was pretty forceful about droplets versus aerosols in the spring, and that it has backtracked a bit about this position, but still waffles.

"WHO has made some updates to its practical guidance, which stemmed from its limited recognition of airborne transmission. However, even WHO's limited updated guidance has not been vehemently communicated or explained to the public. WHO’s lack of clarity and urgency regarding airborne transmission has led citizens, and those in key policymaking roles, to assume that additional precautions are not necessary. We know this is wrong. We know washing hands, distancing, and masks are not enough."

The petitioners and the building scientists want far more emphasis placed on ventilation. "WHO must clearly explain why ventilation measures are needed and update its guidance to recommend facial coverings even when physical distance can be maintained indoors."

Treehugger contacted engineer and lecturer Robert Bean, who has been on Treehugger a number of times, and is one of the organizers; he replied:

"We formed a group spearheaded by Lucia Lara through our combined concern over the WHO and our respective governments' lack of clear direction on aerosols. She is at the top of the organizer lists, along with the core petitioners.
Many government health agencies on our radar screen and others (WHO, CDC, Health Canada, etc.) have noted that society needs to be concerned with poor ventilation in crowded rooms, yet no explanation is forthcoming about why people should be worried. The USCDC waffled several times, removing its guidance on aerosols, then finally posted a position about aerosols and ventilation. Again, the transmission path is not being convincingly communicated to society—the WHO recently released a video on ventilation, which is good but also done without discussing aerosol. So there is a recognition that ventilation and filtration are necessary. Still, everyone is holding short of coming and saying why!!!"

A fundamental question is why the infectious disease experts take such a different approach to the transmission of the virus than the building scientists. Treehugger wondered if there were some kind of turf wars going on:

"There is definitely a disconnect between professionals that should be collaborating. So your basis for turf wars holds some validity; as many in the medical community are working from a medical model, the epidemiology from an epi model, the virologist from the virus model, the aerosols scientists from the aerosol model…public health and so on – but here is the thing…no one denies that ventilation and filtration are essential as a control layer so the building science with industrial hygiene perspective can not be ignored….yet these are studies not taught to the other communities."

Engineer David Elfstrom tells Treehugger that it is because of a different approach to the science;

"One of the breaks appears to be at the infectious disease vs physics level. In the body, that's biology, chemistry. In the air, that's aerosol science. In between is epidemiology. When Infectious Disease [experts] suggest a Randomized Control Trial for portable air cleaners with HEPA filters they run up against physical scientists who are used to doing controlled experiments."

The infectious disease specialists may understand viruses, but they don't necessarily understand air movement, so they kept changing their minds about how to deal with it. Elfstrom continues:

"Without fundamentally accepting and stating the mechanism of inhaled transmission of the infection, governments and public health authorities are creating many prescriptive requirements that are inconsistent."
Chapin 1910

Chapin, 1910

Elfstrom also points Treehugger to Jonathan Mesiano-Crookston, who notes that the droplet theory goes back to 1910, and that the WHO is also relying on studies done by people who are on the WHO guidance committees and wrote a 2013 study done in hospital situations:

"Though knowledge of transmission modes continues to evolve, current evidence indicates that the major mode of transmission of most ARIs [acute respiratory infections] is through large droplets.... Large droplets of this size, because of their weight and size, generally can not remain suspended in the air. Consequently, infection control precautions will only be necessary when the health-care worker comes within 1 metre of the patient. This is the rationale behind the recommendations under 'droplet precautions.'"

Writing from Australia, Dr. Raina MacIntyre explains that this division between droplets and aerosols is silly and outdated.

"The droplet vs. airborne paradigm has driven hospital infection control policy for almost a century, but is based on very old data which has since been disproven. It originates from photographic techniques from the 1930s and 40s which suggested large droplets are expelled within 2m of a patient and fall to the ground rapidly, whereas smaller airborne droplets may exist beyond 2m, for longer periods of time, and that these two modes are mutually exclusive. In fact, droplets of all sizes exist in a continuum, and large droplets can travel further than 2m."

None of this is news. Three years ago my colleague Melissa Breyer was writing about how flu viruses were spread as aerosols, quoting researchers who found that "People with flu generate infectious aerosols (tiny droplets that stay suspended in the air for a long time) even when they are not coughing."

Engineers and architects who understand how air moves (I am an architect and follow this carefully), have been going on about this since early spring. The petitioners are saying enough.

"Airborne transmission of SARS-CoV-2 is a fact. As a result, some countries have already recognized it. In many other countries, informed people are already undertaking measures to protect their families and loved ones. However, not everyone has the same resources or access to information. The only way for protection measures can reach the entire population equally is through local authorities, most of which follow WHO recommendations. Given this reality, the lack of clear guidance from WHO contributes to increasing social inequalities."

They make a number of sensible recommendations that can be reviewed on their website here.