Harvard environmental researcher Joseph Gardner Allen was elated when New York Governor Andrew Cuomo instructed all malls to install high-efficiency particulate air filters capable of trapping the Covid-19 virus, if they wanted to reopen.
Dr Allen, who directs the “Healthy Buildings” program at Harvard T.H. Chan School of Public Health, said, “I’ve been writing consistently since early February about how healthy buildings should be the first line of defense against the novel coronavirus.”
He continued by saying, “I’m really grateful that we have a leader in the country — somewhere — who was finally talking about healthy buildings, ventilation and filtration. That hasn’t happened before. It just hasn’t happened.”
An open letter was sent to the WHO, the US Centers for Disease Control and Prevention as well as other health agencies by a panel of 239 scientists which included Allen, asking all parties to change their public guidelines on the spread of the novel coronavirus.
The letter which was published in early July in the journal Clinical Infectious Diseases, stated current guidelines only focused on “hand washing, maintaining social distancing and droplet precautions”. The scientists said health agencies were ignoring the tiny droplets containing the coronavirus that spray from mouths, became aerosolized and then become airborne, as a possible means of transmission.
A co-author of the letter, University of Maryland professor of environmental health Donald Milton, previously told CNN, “They don’t want to talk about airborne transmission because that is going to make people afraid.”
Professor Milton elaborated further by adding, “The best vaccine against fear is knowledge and empowering people to take care of themselves. Why wearing a mask is important is because it blocks the aerosols at their source, when it is easy to block them.”
Dr Allen who has focused his career on how sick buildings affect worker productivity and performance, said that because the CDC and WHO “have been so slow to acknowledge aerosol transmission is happening, buildings are not putting in appropriate control measures.
Dr Allen continued by saying, “The prudent and pragmatic approach is to acknowledge that airborne transmission is happening and put in the controls. If we find out in five years, that airborne was 5% of transmission, then OK. But what if it’s 20% or 30% and we failed to acknowledge it? That’s a problem.”
The WHO released a new scientific report on July 9th that acknowledged the coronavirus could spread through the air in crowded indoor spaces. The report stated, “In these outbreaks, aerosol transmission … cannot be ruled out. More studies are urgently needed to investigate such instances and assess their significance for transmission of COVID-19.”
The WHO report continued by stating, “Current evidence suggests that transmission of SARS-CoV-2 occurs primarily between people through direct, indirect, or close contact with infected people through infected secretions such as saliva and respiratory secretions, or through their respiratory droplets.”
The CDC has also acknowledged “Covid-19 is thought to spread mainly through close contact from person-to-person,” through “respiratory droplets produced when an infected person coughs, sneezes, or talks.”
Governor Cuomo wanted malls to install HEPA filters with the highest MERV (minimum efficiency reporting value) ratings between 17 – 20 which are more effective than filters with lower ratings.
However, Dr Allen has a slightly different opinion, “HEPA filtration is not always going to be feasible or practical. But there are other filters that can do the job. What is recommended now by the standard setting body for HVAC is a MERV 13 filter.”
University of Massachusetts associate professor of biology Erin Bromage, suggested building owners should look at increasing the amount of makeup air that is brought from the outside, conditioned and brought inside.
Bromage said, “It’s worse in regards to energy, but the more outside air we bring in, the more dilution of the virus we have and then the safer you are.”
Dr Allen summed things up saying, “No one strategy alone is going to work. But if we layer enough of these on top of each other, we can significantly reduce risks.”
18th July 12:30 2020