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Smart Intelligent Air Conditioning and Ventilation - Post-COVID-19 pandemic:Paranoia about un-safe spaces?

You can now count trains, hospitals, cars, offices as places where you have to think twice before stepping in because they are all not safe for you. Virus, germs and pathogens are every where. Some are very deadly of course and some will get you sick. You will have to be very careful when going into a confined space where there is very little ventilation to speak of. And when there is no ventilation, especially when there is no opening for fresh air to seep in, then what you breathe there is just recirculated air and you also breathe in pathogens without your knowledge. Worst, some people do not show any symtoms when inflicted with illness and they go around spreading pathogens while talking at the top of their voice as if they are the god ordained apostles. But to your knowledge, allmost all comfortable spaces have air conditioning but no ventilation because they can't afford to have leakages that can drive up their energy cost! So what to do? Well, how about an intelligent air conditioning and ventilation system that will not only reduce your energy bill, but will also go a long way to save you from being infected with the deadly virus!

But how is Covid-19 virus transmitted?


A case study of how a Chinese restaurant air conditioning system help spread Covid-19 – should we then redesign the air conditioning system? Here is a picture of how air conditioning help spread diseases published in a letter from several scientists in Guangzhou addressed to the Emerging Infectious Diseases Journal, based at the US Centres for Disease Control and Prevention (CDC.)


covid-19 spread by air conditioning



* Patient A1 was infected with COVID-19, but asymptomatic when they dined with their family (A2-5) on January 24.

* The AC picked up air droplets from the breath of patient A1 and blew them around the room. Water droplets usually don’t travel more than a meter without assistance.

* Nine other people (four members of A, three of B, and two of C) later tested positive for COVID-19 and were traced to to A1.


“The key factor for infection was the direction of the airflow,” a group of scientists from Guangzhou noted and felt worrying because the implications could be wide ranging as we are heavily pampered by air conditioned spaces and something we could not do without. It is no wonder why our health care providers are easily infected by Covid-19 in their working environments! The issue seems to be an enclosed space; air is recycled ad infinitum. Perhaps we need to redesign the air conditioning system to better suit the situation that we are facing now and the foreseeable future. Air conditioning was designed in 1902 and was widely used since the fifties. It was designed to efficiently cool a confined space; no windows to bring in fresh air. Is there then a solution? Yes, it is called ‘Open Space Air Conditioning.’



Here is a graphic of how a virus is spread


The Great Danger from Micro Droplets

Micro-droplets of infectious coronavirus could stay airborne for hours and social distancing practices may not be enough to stop infection and spread, experts said. In an open letter to the international science community, 239 health practisioners urge their colleagues to take airborne transmission seriously as COVID-19 cases rise in many parts of the USA. The scaring part is that though most of the heavier respiratory droplets don’t reach more than 6 feet from a person's mouth, aerosolized droplets (micro droplets) can span an entire room and hang in the air for several hours, this because there is no air ventilation, only recirculated air; according to the letter published July 6 in the journal Clinical Infectious Diseases. Governments are starting to be highly concerned that tiny droplets can carry SARS-CoV-2. And after months of denying the importance of this, the World Health Organization is reconsidering its stance.

In response to the commentary, the WHO has softened its position, saying in a press conference on 7 July that it will issue new guidelines about transmission in settings with close contact and poor ventilation. “We have to be open to this evidence and understand its implications regarding the modes of transmission, and also regarding the precautions that need to be taken,” said Benedetta Allegranzi, technical leader of the WHO task force on infection control. WHO had maintained all along that the virus is spread mainly by contaminated surfaces and by droplets bigger than aerosols that are generated by coughing, sneezing and talking. These are thought to travel relatively short distances and drop quickly from the air, hence the good of wearing a musk and practising physical distancing. But now, that is not enough as the issue of adequate air ventilation and air exhaustion (which is non existing in most of our public spaces) can become a game changer.


One thing good about about lockdowns - flu-like illness came crashing south!

Rates of flu-like illness drop to 'almost zero' during lockdown; that is according to New Zealand's Director-General of Health Dr Ashley Bloomfield. She further added that staying at home and 'breaking the chain of transmission' for the Covid-19 outbreak had also broken the chain of transmission for other respiratory illness in the community too. Meanwhile, early data from the FluTracking survey, an Australian Research entity which asks respondents simple questions about cough and fever symptoms every week, suggests that the incidence of those symptoms plummeted after physical distancing measures were introduced in Australia from mid-March. Flu-like symptoms fell from a peak of 1.6 per cent to a low of 0.3 per cent. The incidence of these symptoms in the community at the same time last year was 1.8 per cent. That's a difference of 1.5 percentage points (83.3 per cent) and represents a historic low for the survey.So how does it tick?


The most probable answer is that people were made to stay away from public places where there is very little ventilation. And when there is no ventilation, you just breathe in recirculated air which is most likely infested with pathogens; coming from people who sneeze, cough and talk aloud. That is also the reason why people tend to get sick easily unknowingly catching the bug while doing their everyday things. If someone falls sick in your office, then it would not be surprise that others would catch the sickness too. Experiments had shown that you can transmit the germs even while you are talking! Should we not then take a serious look at the HVAC system that is running our spaces with the aim of re-engineering the whole HVAC thing even though it will 'cost an arm and leg?' It would also not surprise us if the general practitioners (doctors) also tell the same story that very few people came to their clinics with flu symtoms! Concerned Doctors have advised that restaurants and other public places not to open for dine-in after lockdowns are lifted if they have not made alterations to their ventilation system. This is a critical call and it will mean whether we will make it through to the post coronavirus era or remain in lockdowns forever.


When transmission of virus is concerned, we have to talk about this guy called the 'Super Spreader' and he or she is definitly the guy that we should be weary about. Unfortunately, the guy does not normally show early symtoms and we have no way to identify them until when the whole thing flared up. Here is a Super Spreader Article that you should be reading. Meanwhile,


From another corner, a prestigious scientific panel told the White House Wednesday night that research shows coronavirus can be spread not just by sneezes or coughs, but also just by talking, or possibly even just breathing. "While the current (coronavirus) specific research is limited, the results of available studies are consistent with aerosolization of virus from normal breathing," according to the letter, written by Dr. Harvey Fineberg, chairman of a committee with the National Academy of Sciences. That sums it, we are not safe in any environment but we will need to be very careful when we enter an enclosed space; you never know where the virus lurks.



Open Space Air Conditioning – Intelligent Air Conditioning and Ventilation System to better prevent the spread of coronavirus!


intelligent spot air conditioning system


We are now capable of bringing air conditioning (or heated air) to an open space or space that have provisions of allowing fresh air to enter the space. It also means that stale air (virus infested air) can be filtered (to kill off the virus) and then exhausted. The new system has two components. One of which is a redesigned air conditioner out-let nozzle and the other is a redesigned ventilation system that caters to the new safer environment.


New ventilation system to have better air quality to prevent spread of covid-19


intelligent air conditioning and ventilation

Intelligent air conditioning with smart ventilation to boot


conventional air conditioning - side draft

conventional air conditioning - air flow from side to side, thus helping transmit pathogen from one person to another

intelligent air conditioning - down draft

intelligent air conditioning - air flow from top to down, thus averting transmission of pathogen from one to another

In view of the Covid-19 pandemic, and as we know that there is very little air ventilation to speak of in most of the spaces we spent out time in, it is critical that we have an air ventilation done right by having air flow from the top to the bottom as compared to the conventional way of having the air flow from side to side. It is not only important for fresh air to be inducted into the environment but we must also ensure that the air flows from top to the bottom. This however has not yet being mandated by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) but we believe it will be so as a matter of time since our lifes are greatly impacted by the epedemic. On the other side of the Atlantic, Eurovent (europe's industry association for indoor climate, process cooling and food cold chain technologies) have made these recomendations that 'ventilation rates should be increased from outdoor air' as well as 'extending the operation time of the ventilation system' and further embed proper filters in the ventilation.


If indeed that the coronavirus is dispersed through micro droplets floating in the air, then we will have to ensure that all precautions to have these micro droplets be directed away from people like dumping it to the floor. A floor level air exhausting system (air vacuuming) is then employed to suck out the pathogens that have landed on the floor. Alternatively, the polluted air could be exhausted through an outlet valve designed on the floor; this is however a new concept but might be made mandatory for the sake of preventing the recirculation of pathogen infected air in the environment. It might be a good idea for HVAC Engineers to take a good look at their existing systems which might come up short because we are now facing a great invisible threat from a possible slow mutating of COVID-19.


Here at Riverria Iskandar Malaysia we have planned for an 'Intelligent Ventilation' in our room spaces that is intelligent enough to detect whether there is any occupant in the room. It will automaticaly shut off the air inlet valve and the fans to conserve energy when the room is empty. When it detects that there is occupant in the room space, it will open up the valve and on the fan to allow an aportion of air to enter, varying it in accordance to the number of occupants in the room. It also work in a smart way in that it is connected to the network so that it could be programed to ventilate the space prior to the entry of the occupant.


The Intelligent Ventilation system also has a smart outlet valve (preferably designed on the floor) to help exhaust out the air which it works in coordination with the inlet valve. There is also embeded filters (HEPA) at both terminals so that pathogens are got rid off. Not only that the Intelligent Ventilation also comes with ultra violet light semination at both ends. This makes the air safe for inhaling but if pathogens were to be brought ( unintentional) into the space by humans, then it will work by coordination with the Intelligent Air Conditioner (nozzle) to deliver a right passage for the breath (may have pathogens) the people exhaled out towards the floor level away from people.This is an important system to have if we want to avoid the spread of pathogens, in particular Covid kind of virus.


floor level exhaust ventilation

Near floor level air exhaust


floor level exhaust ventilation

Floor level exhaust ventilation system




floor level air filteration

Portable air filteration and germ killer


An alternative to air ventilation is to employ a portable air filter which will also kill any pathogens. The portable air filter (can also provide slight air cooling) should come with HEPA filters and also an ultra violet dosing gun. This is to help draw in air exhausted by the occupant and then leading them to be exposed to ultra violet light so as to neutralise the pathogens. This system is most easy to set up as it does not need to re-construct the infrastructure but you will have a tradeoff in that there won't be any fresh air drawn in.


How does the Intelligent Air Conditioner make the difference?

Well, you will notice from the above diagrams that the air coming from the air conditioner is moving downwards. If the breathe from the person sitting in the room is in anyway compromised, that is if it does contain pathogen, then it is evident that the compromised air is pushed downwards towards the floor and not to you. You will then not have to breathe in the compromised air and you will therefor not going to catch it in your face. You will realised that this is different when you are using a conventional air conditioner where the air flow travels horizontally and is not forced downwards. And if you are sitting opposite the person, the intelligent air conditioner will direct another air flow downward towards you through another nozzle, thus creating an air barrier to shield you from the air breathe out by the other guy. That is the beauty of the intelligent air conditioner like is built for post-covid era!


New Intelligent Ventilation for Riverria Iskandar Malaysia Condominiums to fight COVID-19


The new ventilation system will take into consideration the need to bring in fresh air either through a conventional window or an open door. The idea is to cool a particular space whilst taking into consideration of an entry of fresh air and an exhausting of stale air. Would it then be efficient for the air conditioning to take care of fresh air inflow and also the exhausting of already cooled stale air? It’s certainly not possible you may think because there will be a lot of leakages, yes? Well, that is where the new air conditioner outlet nozzle is designed to handle.


The new Industry 4.0 endowed Air Conditioner Outlet Nozzle


Designed from the ground up and patent pending, the new Air Conditioner Outlet Nozzle is built with intelligence as it is able to detect how many occupants and which spaces need to be cooled in real time basis. Thus it is capable of running with high efficiencies as it does not waste energy trying to cool spaces which have no occupant (people) like ceilings and spaces where furnitures are laid. And when the environment changes like having people moving in and moving out at the same time, it will use its intelligence to gauge in which direction it will direct its jet of cool (or hot) air; this being done by the fully articulated nozzles that can change its configuration to deliver maximum cooling with the least amount of energy. So even if you have openings like a window or an opening door when someone comes knocking in, the intelligent nozzle will reconfigured itself to train its cooling air to the new demanding conditions.

In short, the new nozzle is intelligent and capable of detecting where the demand is and also determining how much to cool. As a further improvement of the intelligent air con nozzle, it is capable of detecting the individual body temperature (focus on the forehead) and it will notify through a mobile application to the master controller so that a precaution can be taken. This feature will be very helpful where we need to identify in real time the person with an abnormal body temperature. All this is done automatically (with artificial intelligence assistance) without having human inputs and when there is nobody in the room; it will automatically shut itself down and return to its standby mode. This new system is capable of a 60 percent reduction in fuel bill despite having to cater to an inflow of fresh (and sanitised) air from the intelligent ventilation system; also an air (also sanitised) exhausting system.

Importance of Good Air Ventilation

CO2 (carbon dioxide) concentrations in outdoor air typically range from 300 to 500 ppm. Thus indoor CO2 concentrations of 1000 to 1200 ppm (parts per million) is considered on the high side. Now, if you sleep in an air conditioned room where there is very little ventilation, the level of carbon dioxide could reach a level of 1,000-2,000 ppm in a very short time which according to health experts can cause drowsiness. With further upping of level of CO2, say 2000 to 5000 ppm (if you consider that there are at least two persons sleeping), then it is normal to feel headaches, sleepiness, stagnant stuffy air, poor concentration, increased heart rate and slight nausea even though you may be sleeping and not aware of it.

That is certainly not a healthy way of life and normally people are not aware of. In order to rectify the situation of poor air quality in an enclosed space, there must be ventilation designed into the system. Air should also flow from the top to the bottom and preferably having it filtered and sanitised before allowing air in and also filtered and sanitised before exhausting it out and preferably at the floor level. This should be the new standard in light of the presence of coronavirus.


Intelligent Ventilation for Vehicles

intelligent vehicular ventilation

intelligent vehicular ventilation


Like all spaces, we have to ensure that we have good ventilation and be safe from coronavirus infection. We will need to have air inflow from outside and air outflow to outside of the vehicle, be they cars, buses, trains and aircraft. In order that that the vehicle air conditioning work effeciently, we will need to use an intelligent air conditioner that is specially designed for vehicular spaces. In order that the intelligent air conditioner work efficiently, it must be able to determine which spaces to cool as it does not waste energy cooling those spaces that are devoid of passengers. The intelligent vehicular ventilation system takes into consideration of inflow of air from outside the vehicle. It also takes into consideration of an out flow of air from the vehicle as shown by the above diagram.

Since we are having a leakage of air (exhaust) from the vehicle, we will need to compansate it by having the air con work only on those spaces with an occupant (this is more acute in confined home spaces). So if we only have the driver, the air con nozzle will only direct cool air (or hot) to the direction of the driver. This is made possible because the intelligent air conditioner is able to adjust to the number of passengers in the vehicle. The intelligent air con is also able to direct the air flow from the passenger to the out flow valve designed on the vehicle pillars (with the aid of an internal exhaust fan) such that the breath of the passenger (could be infested with pathogen) is quickly sanitised and exhausted out of the vehicle; thus preventing the back passengers (also side passenger) from inhaling the out flowing breath of the front passengers. As all intelligent ventilation is capable of doing, there will be filtering and sanitizing devices fitted to both the entry and exit points of the system; filters and ultra violet emitters will be used.


elevator ventilation

elevator-new death pit


Elevator Space - Very Little Ventilation to speak off

We all know that there is very little ventilation when we use the elevators. Some of them do come with air conditioning but not air ventilation so in the light of spread of coronavirus, we would definitely feel claudaphobic as we breathe in what others exhale out. And the germs! Yaak. But that was the way how elevators was designed. However because of the presence of virus floating all around us, it would be better that we do a re-design of the system which should include adequate ventilation. The new design will look like this.


intelligent elevator ventilation

Elevator Ventilation as it should with air entering from the top and flowing out at the bottom! With this method, you won't have to breathe in what other exhale!


shopping mall

getting the flu visiting shopping mall?

Shopping Malls - the likely place where you get infected with the flu virus!

Shopping Malls are great places to while away your time and almost everyone including the children would love to spend their leisure time there. However, there is a suspicion among health practisioners that shopping mall is the most likely place where you can contract influenza especially the children. How is it so? Well, shopping malls are usually crowded with people and that is where sick people also visits. Sneezes, coughs and loud voices normally provide a convenient way to spread the virus. It is certainly true for corona virus and many other forms of diseases. Making it worse is the fact that there are very little ventillation in the shopping malls and it is also true that the air conditioning is normally centralised, so it is obvious that visitors do breathe in what others exhale because you only have recirculated air in the environment.


There seems to be very few options if we were to opt for changing the ventillation system as it would normally require a substantial sum of money to do so. So what can be done about it? In the face of pandemic, it would be advisable to add at least some form of device to counteract the virus that are suppose to be trapped in the air conditioning ducts. One viable but not tested solution is to have these ducts radiated with ultra violet rays as some of the shopping malls already have instituted this iradiation technique as a stop gap measure until a better solution comes about. Additionally, ground level ventillation could be instituted as it is easier to do so.



How safe are you travelling in an aircraft?


A report from US’s Centers for Disease Control and Prevention:Volume 26, Number 11—November 2020.

Abstract

Four persons with severe acute respiratory syndrome coronavirus 2 infection had traveled on the same flight from Boston, Massachusetts, USA, to Hong Kong, China. Their virus genetic sequences are identical, unique, and belong to a clade not previously identified in Hong Kong, which strongly suggests that the virus can be transmitted during air travel. In 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in China, ultimately causing the coronavirus disease (COVID-19) pandemic. Many persons with SARS-CoV-2 infection have since flown into and out of COVID-19–affected areas (1). Some countries quarantine arriving passengers. Airports are also screening passenger body temperatures before boarding and after arrival. Recent investigations have shown that SARS-CoV-2 can be transmitted before symptom onset, posing a challenge to outbreak control (2). Although risks for SARS-CoV-2 transmission have been extensively investigated, in-flight transmission of the virus has not been formally confirmed. Airline staff members have voiced concerns over acquisition of SARS-CoV-2 infection (3). Given that flights are still departing to and from COVID-19–affected countries, determining whether in-flight transmission of SARS-CoV-2 occurs is essential.


The Study

We examined public records for 1,110 persons with laboratory-confirmed COVID-19 in Hong Kong, China, recorded from January 23 through June 13, 2020; we used Centre for Health Protection (CHP) public records and the Vote4HK COVID-19 in HK database for case-patients who had traveled before diagnosis (4,5). At the time, the Hong Kong government had yet to introduce mandatory quarantine and airport screening (6). We identified a cluster of 4 persons with COVID-19 (henceforth referred to as patients A–D) associated with a commercial flight that departed from Boston, Massachusetts, USA, on March 9 and arrived in Hong Kong on March 10, 2020.

The airplane, a Boeing 777-300ER, flew for »15 hours and carried a maximum of 294 passengers. The cluster comprised 2 passengers and 2 cabin crew members. Although these persons did not fulfill the criteria for SARS-CoV-2 testing at the time of arrival, results of reverse transcription PCR conducted in local healthcare settings within 5–11 days of arrival were positive. All 4 case-patients subsequently recovered (Appendix Figure 1). Patients A and B were a married couple. Patient A was a 58-year-old man with underlying disease who sat in a window seat in business class on the airplane (Appendix Figure 2). On March 10, fever and productive cough developed; on March 13, he had mild abdominal discomfort, followed by diarrhea 2 days later. His 61-year-old wife, patient B, also had underlying illness. She sat directly in front of him in a business class window seat.

On March 10, she had a sore throat. One day later, fever and cough developed. As their symptoms evolved, they sought healthcare and were hospitalized on March 14. On March 15, respiratory samples (collected March 14 for patient A and March 15 for patient B) were positive for SARS-CoV-2. No public record indicates what their underlying diseases were or whether these 2 passengers were symptomatic during the flight. Before the flight and within the 14-day incubation period, they visited Toronto, Ontario, Canada (February 15–March 2); New York, New York, USA (March 2–5); and Boston (March 5–9). CHP classified the couple as imported cases into Hong Kong.

Patient C was an asymptomatic 25-year-old man identified through contact tracing by the Hong Kong government and the airline as a close contact of patients A and B. He was a Hong Kong–based business class flight attendant who served patients A and B during the flight. After patients A and B received their diagnoses, the airline informed patient C, and he attended an outpatient clinic on March 16. He was positive for SARS-CoV-2 on March 17 and was subsequently quarantined and hospitalized. Patient C stayed in Boston during March 5–9.

Patient D was a 51-year-old female Hong Kong–based flight attendant on the same flight. Fever and cough developed on March 18, SARS-CoV-2 test result was positive on March 21, and patient D was hospitalized. There is no publicly available information of her travel history before the flight or her contacts with the other patients on or after the flight. Descriptions of the disease experienced by patients C and D were unavailable. CHP categorized patients C and D as close contacts of a person with an imported case.

To generate genetic evidence for transmission between the 4 patients, we sequenced their viruses. Samples were collected under public health authority, and individual patient identities are known to CHP. Retrospective analysis of leftover samples without individual consent was permitted under local regulations and approved by the institutional review board of the University of Hong Kong/Hospital Authority West Cluster (reference UW 20-168) and the London School of Hygiene & Tropical Medicine Ethics Committee (reference 22384). Stored upper respiratory samples were sent to a World Health Organization reference laboratory at the University of Hong Kong.

We deduced near full-length genomes (sequence length >29,760 nt) by using the Illumina sequencing method and previously described primers and protocol (7). All deduced sequences had a minimum coverage of 100. While sequencing and analyzing the specimens, we were blinded to patient status as passenger or crew. Figure. Phylogenetic tree of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses isolated from passengers and airline crew members who traveled on the same flight from Boston, Massachusetts, USA, to Hong...

The near full-length viral genomes from all 4 patients were 100% identical and phylogenetically grouped to clade G (Figure). Other than these 4, none of the 189 viral sequences deduced from samples collected in Hong Kong (January 21–May 12, 2020; GISAID, http://platform.gisaid.orgExternal Link), belong to this clade (data not shown) (K.S. Leung et al., unpub. data, https://www.medrxiv.org/content/10.1101/2020.03.30.20045740v2External Link). Conversely, in March 2020, virus sequences related to those of patients A–D with only 2 nt differences were isolated in Toronto, New York City, and Massachusetts (Table), making it plausible that patients A and B acquired a similar virus during their visit. Worldwide during January 10–June 13, »30,000 complete SARS-CoV-2 genomes with high coverage were deposited into the GISAID database. None shares 100% identity with the sequences of the viruses in the cluster reported here.

Top Conclusions

Given the case histories and sequencing results, the most likely sequence of events is that one or both of passengers A and B contracted SARS-CoV-2 in North America and transmitted the virus to flight attendants C and D during the flight. The only location where all 4 persons were in close proximity for an extended period was inside the airplane. Passengers and cabin crew do not generally go through the same check-in process at airports before boarding. Although we cannot completely rule out the possibility that patients C and D were infected before boarding, the unique virus sequence and 100% identity across the whole virus genome from the 4 patients makes this scenario highly unlikely. Patient D may have acquired infection from patient C, but because their test results were positive within 1 incubation period, it is more likely that patient D was infected by patient A or B. We therefore conclude that these 4 patients belong to the same in-flight transmission chain. Our results strongly suggest in-flight transmission of SARS-CoV-2.

No other COVID-19 cases associated with this flight have been identified. We were unable to quantify the virus attack rate on this flight because not all passengers were tested. Previous reports of probable in-flight transmissions of SARS-CoV-2 lack genetic evidence (8,9). During January–March 2020, the International Air Transport Association received 3 reports of suspected in-flight transmission (10). Contact tracing of 2 passengers who flew from China to Canada has yielded no indication of secondary infections from the flight (11). Nonetheless, SARS-CoV-2 test results have been positive for hundreds of flight attendants and pilots; at least 2 have died (12,13). Our results demonstrate that SARS-CoV-2 can be transmitted on airplanes. To prevent transmission of the virus during travel, infection control measures must continue.

Acknowledgments and Citations

Edward M. Choi, Daniel K.W. Chu, Peter K.C. Cheng, Dominic N.C. Tsang, Malik Peiris, Daniel G. Bausch, Leo L.M. Poon , and Deborah Watson-Jones Author affiliations: London School of Hygiene & Tropical Medicine, London, UK (E.M. Choi, D.G. Bausch, D. Watson-Jones); The University of Hong Kong, Hong Kong, China (D.K.W. Chu, M. Peiris, L.L.M. Poon); Department of Health, The Government of Hong Kong Special Administrative Region, Hong Kong (P.K.C. Cheng, D.N.C. Tsang); Public Health England, London (D.G. Bausch); National Institute for Medical Research, Mwanza, Tanzania (D. Watson-Jones) Dr. Choi is an assistant professor at the London School and Hygiene & Tropical Medicine. His research interests include viral infections and vaccine development.


Appendix


Volume 26, Number 11—November 2020

Dispatch

In-Flight Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 Edward M. Choi, Daniel K.W. Chu, Peter K.C. Cheng, Dominic N.C. Tsang, Malik Peiris, Daniel G. Bausch, Leo L.M. PoonComments to Author , and Deborah Watson-JonesComments to Author Author affiliations: London School of Hygiene & Tropical Medicine, London, UK (E.M. Choi, D.G. Bausch, D. Watson-Jones); The University of Hong Kong, Hong Kong, China (D.K.W. Chu, M. Peiris, L.L.M. Poon); Department of Health, The Government of Hong Kong Special Administrative Region, Hong Kong (P.K.C. Cheng, D.N.C. Tsang); Public Health England, London (D.G. Bausch); National Institute for Medical Research, Mwanza, Tanzania (D. Watson-Jones)


covid virus study table
*These 4 viral genomes are unique among the sequences deposited into the GISAID database (http://platform.gisaid.org) January 10–June 13, 2020. They contain 6 polymorphisms compared with the WIV04 reference sequence of SARS-CoV-2, 3 of which are nonconservative. SARS-CoV-2 genomes that differ from these by 2 nt had been reported from Massachusetts, USA; New York, USA; and Ontario, Canada, in March 2020. SARS-CoV-2, severe acute respiratory syndrome coronavirus 2. †A 2019 reference sequence from a patient in Wuhan, China (hCoV-19/Wuhan/WIV04/2019). The nucleotide positions shown are relative to this reference sequence (GISAID accession ID EPL_ISL_402124). ‡No. nucleotide differences relative to the virus genomes of patients A–D. §Nonconservative polymorphism at nucleotide position 11083, which corresponds to a Leu (TTG) to Phe (TTT), L37F, amino acid change in the NSP6 protein. ¶Nonconservative polymorphism at nucleotide position 14408, which corresponds to a Pro (CCT) to Leu (CTT), P323L, amino acid change in the NSP12 protein. #Nonconservative polymorphism at nucleotide position 23403, which corresponds to an Asp (GAT) to Gly (GGT), D614G, amino acid change in the spike protein.


It would now be clear that there is a problem with the aircraft ventilation as we know of it! So what are we going to do about it? But not all aircraft have the same ventilation system. A good example is the system used by JAL. A better system to confront Covid-19 is to increase the individual flow vents from the top of the cabin and to completely suck out the air through the bottom of the seats.

commercial aircraft ventilation system

The aircraft receives external air through the engine *The Boeing 787 uses electric compressors to feed external air directly into its air-conditioning system, rather than from the engine. The air-conditioning system adjusts the compressed air to an appropriate temperature and supplies the clean air throughout the cabin. The differential pressure will push the air inside the cabin toward the belly of the aircraft and is discharged from the cabin pressure control valve. For the ATR turboprop aircraft operated by Hokkaido Air System and Japan Air Commuter, fresh air replaces the cabin every 4-6 minutes. As for the SAAB340B aircraft operated by Hokkaido Air System, fresh air replaces the cabin every 4-5 minutes. Both aircraft are not equipped with HEPA filters but the ventilation system allows fresh air to be supplied from the overhead compartment and extracted at the bottom of the aircraft.