Covid-19 Infection At Supermarket Possible
Research in Finland conducted in four separate research institutes including Aalto University, VTT Technical Research Centre of Finland and the Finnish Meteorological Institute showed that there is a risk that COVID-19 could be spread in supermarkets due to airborne transmission.
Using an average supermarket layout researchers showed that once someone coughs or sneezes then leave behind extremely small aerosol particles carrying the coronavirus. Aalto University Assistant Professor Ville Vuorinen said "These particles could then end up in the respiratory tract of others and could travel as far as over two supermarket aisles.”
So is there a real risk that you could get infected by airborne contamination of COVID-19 at the supermarket ? Well maybe, and certainly in any room that contains a large number of people in a confined space like a hospital waiting room or cinema.
I have spent the last thirty years designing and validating Pharmaceutical and Medical Device facilities and Hospital biocontainment systems where the sole aim is to prevent the transfer of microbiological contamination from the immediate environment to medical products and medical staff and patients.
Using “real time” air quality testing we know for example that if we have a non-sterile secondary packing room for boxing up surgical masks with an office quality air filtration system which filters the air in the room only three times per hour we see a rapid build-up of bacteriological and particulate air contamination over time.
We also learnt that if the female packing staff wore just normal street clothes, predominantly skirts, then we would see a massive increase in airborne yeast concentrations.
Humans are very dirty organisms, we shed around one million dead skin cells per day.
Every minute an adult human wearing street clothes will release around 50,000 particles per minute into the immediate environment. These particles include dead skin cells ,makeup particles, bacteria, yeasts, fungi and an assortment of clothing fabric and dust particles and if they are not filtered out or diluted by fresh air recirculation they build up in the room.
We have also learnt over decades of real time testing that, while the WHO claims that COVID-19 is not airborne, bacteria and viruses can hitch a ride on microparticulate airborne skin debris and dust particles and can be transported over long distances.
Now if you are walking on a path in Ponsonby and you stay three meters away from another human being then you will not be likely to come into contact with their possibly infectious surrounding biological tsunami because their infectious particles are rapidly dispersed into the ambient environment.
However in a closed room environment like a hospital waiting room which has only three room air changes per hour then the bacteriological and particulate contamination is recirculated within the room to produce a bacteriological and particulate bioaerosol or “fog” which can allow viruses to remain suspended and airborne over long distances and sets the scene for the infection of everyone in the room.
The four key determinants as to the possibility of contracting COVID-19 via airborne contamination are the number of people in the room who are infected, the number of the people in the room per square meter, the number of room fresh air replacements per hour and the types of filters used in the air-conditioning system.
It is therefore not surprising that the major clusters of COVID-19 infections in New Zealand have been attributed to weddings, conferences and colleges which had very high concentrations of people per room and very little fresh air replacements and no air-conditioning bacteriological filters.
The good news is that most supermarkets are limiting the number of people into the supermarket at any given time so hopefully the airborne bioaerosol bioburden will be relatively low and your chances of contacting COVID-19 via airborne transmission will, be relatively low.
Those people quarantined in Hotel facilities for long periods of time with common interconnecting air-conditioning systems may not be so lucky.
Fifty people in isolation with a common interconnecting hotel return air system will be producing over four billion particles per day and this provides a bioaerosol -fog capable of carrying COVID-19 over large distances.
However the most likely place you will acquire a bacterial or viral infection in New Zealand is in hospital.
We have the second highest rate of Hospital Acquired Infections in the developed world nearly twice that of Italy.
A new study examining air samples from hospital wards in China with COVID-19 patients has found the virus can remain airborne for up to four meters, -- twice the distance current guidelines say people should leave between themselves in public.
So with the upcoming Flu season looming get your Flu vaccination, open your windows get some fresh air and don’t go anywhere where there is a large concentration of people in a small confined space.
You could get infected by viruses and bacteria surfing on someone elses dead skin cells.
No one wants this.
Sir Ray Avery