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 Table of Contents  
SHORT REPORT
Year : 2020  |  Volume : 8  |  Issue : 1  |  Page : 29-32

Air travel in COVID-19 pandemic


1 NIMS Hospital, Jaipur, Rajasthan; Infecion Control Consultant Shroff Eye Hospital, Delhi, India
2 NDMC Medical College and Hindu Rao Hospital, Delhi, India

Date of Submission12-Jun-2020
Date of Acceptance18-Jul-2020
Date of Web Publication4-Sep-2020

Correspondence Address:
Dr. Vandana Saini
NDMC Medical College and Associated Hindu Rao Hospital Delhi
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jpsic.jpsic_12_20

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  Abstract 


To limit the spread of coronavirus, most of the countries had applied lockdown, restricting movement of people, ban on public transport and air travel. The World Health Organization (WHO) advises against the application of travel or trade restrictions in countries experiencing COVID-19 outbreaks for a longer period of time. These lockdowns should be short in duration and be regularly reviewed as the situation evolves. After lockdown, most of the countries have started airline services again, but society in general is sceptical about safety of air travel and the spread of disease in the present COVID time. Aircraft appears to be airtight chamber with passengers sitting very close to each other, so people get worried about getting infection from fellow travellers. Unfortunately, most of the regulations are on chemical contaminants in the flight cabin but are silent on bacteriological, viral and other microbial contamination of air in the cabin. Still, it has been observed that the risk of infection in flight is comparable to train and car and might be much lesser. To maintain air quality, airplanes have High-Efficiency Particulate Air filters which can capture 99.9% of particles (bacteria, fungi and larger viruses or virus clumps) of 0.1–0.3 μm in diameter. Low concentrations of bacteria and fungi have been found in air cabin at levels that are not thought to pose any health risk. Air is replaced with fresh air every 2–4 min in the aircraft. Besides that, ventilation systems on planes are set up in zones; air is shared between a small group of people only. Although the risk of catching something, airborne on a plane is lower than in many other confined spaces because of the filters and air exchange ratio but risk of infection through contact is still possible, so if a person fly observe contact precautions, for example, hand hygiene and use face cover.

Keywords: Air travel, COVID-19, pandemic


How to cite this article:
Saini N, Saini V. Air travel in COVID-19 pandemic. J Patient Saf Infect Control 2020;8:29-32

How to cite this URL:
Saini N, Saini V. Air travel in COVID-19 pandemic. J Patient Saf Infect Control [serial online] 2020 [cited 2020 Sep 25];8:29-32. Available from: http://www.jpsiconline.com/text.asp?2020/8/1/29/294369




  Introduction Top


Director-General of the World Health Organization, on advice of the Emergency Committee convened under the International Health Regulations (2005), declared an outbreak of COVID-19 a public health emergency of international concern on 30th January 2020. COVID-19 is an infectious disease that spreads through droplet. Communicable diseases are the single most important cause of ill health globally, constituting as high as 44% of the total diseases.[1] Amongst the top ten causes of deaths, communicable diseases stand in the seventh position, with lower respiratory tract infections on top.[2]

The transmission of respiratory virus is mainly through air and droplets. These droplets fall fairly close to where they originate. Hospital's guidelines for influenza define exposure as being within 3–6 of an infected person for 10 min or longer.[3]

So far, COVID-19 virus has spread to 213 countries of the world and 35 states and union territories of India, infecting more than 71 lakh population of the world. To limit the spread of infection, most of the countries have taken lockdown measures and suspended public transport including flights.

Movement restriction of people and goods during pandemic is not proven to be effective in most situations; this may divert resources, may also disrupt businesses and has negative social and economic effects on the affected countries. However, in certain circumstances, restricting movement of people may prove temporarily be useful, mainly to curtail the transmission of infection and help in preparing for the challenges ahead, such as strengthening infrastructure, increasing the number of beds and testing capability.

The WHO also advises against the application of travel or trade restrictions to countries experiencing COVID-19 outbreaks for a longer period of time.[4] Travel restrictions at the beginning of an outbreak may give time to the authorities, even of a few days, to implement effective measures to contain the pandemic. Limiting the movement of people should be based on public health risk. These should be short in duration and be regularly reviewed as the situation evolves.

After lockdown, most of the countries have started airline services, but society, in general, is sceptical about the safety of air travel and the spread of disease in the present pandemic.

It is important that environment in the aeroplanes is clean and does not become the source of infection. Most of the regulations are on chemical contaminants in the flight cabin but are silent on bacteriological and viral contamination of air in the cabin. The Federal Aviation Regulations are on ventilation regulations for carbon dioxide, ozone, temperature, humidity, cabin pressure, etc.

Without proper ventilation, the aircraft cabin becomes the tightly sealed chamber, which is an ideal environment for the spread of bacteria, viruses and fungi. Passengers and flight crews are exposed to one another's respiratory ailments as well as high levels of carbon dioxide and other gases including vapours and fumes from materials and chemicals inside the aircraft. However, it has been observed that the risk of infection spread through flight is lower as compared to train and car travel.

Infection in the aircraft will depend on air quality of the cabin. There are four major issues with the air quality:

  • Oxygen concentration
  • Contamination of cabin air with virus, bacteria, fungi, etc
  • Temperature and humidification
  • Pollution with pesticides on routes to countries which do not want pest to enter their country and hence the use of pesticides to prevent this.


Altitude at which aeroplanes fly, oxygen concentration usually remains about 21%, but the air pressure decreases in such way that does not allow humans to breathe easily. To overcome this, hot compressed air at high pressure is drawn from the plane's engines, cooled and directed into the cabin to supply breathable air.

At times due to possible faults in the engine seals, it may lead to heated engine oil, hydraulic fluids and organophosphate (used as lubricants for the engine's metal parts) contaminate the cabin air. These health effects are called as 'aero toxic syndrome', but various Civil Aviation Authorities maintain that there is no scientific evidence that shows this condition exists.

For maintaining air quality, aeroplanes have the following system in place.


  Ventilation Systems Top


Planes are engineered to maintain an air pressure up to 8000 feet that is to keep air pressure same as found at sea level. Until the early 1980s, the ventilation systems on aircraft are used to provide100% fresh air to the cabin. In flight, fresh air is bled off from compressed engine air and diverted to the passenger cabin. This robs the engine of some of its thrust. To achieve a given level of thrust, more fuel is required to provide the thrust and the passenger air cabin supply. With an increase in expenditure in fuel prices, airlines searched for ways to save energy. After some experimentation in the early 1980s, the major aeroplane manufacturers began recycling part of their ventilation air. If some of the passenger air can be filtered and recirculated, less engine air is needed, and more of the fuel's energy can be devoted to flying the aeroplane. In 1993, this type of ventilation system saved about $60,000 per plane.[5]

Ventilation, with recycled air, increases the hazards of cabin air quality. In addition to the ventilation systems on newer aircraft which recirculate the air, another cause of the reduction in fresh air is the fact that 'flight crews on-most aircraft can regulate the Environmental Control Units (ECU), or airpacks, that deliver fresh air' to the cabin.[6] This 'flow control' allows crews to change the air flow depending on the number of passengers on the plane. In this day of fuel conservation, airline carriers may encourage their flight crews to operate an ECU at a lower level than is appropriate.[6] This reduction of fresh air circulation effectively reduces the operating costs of the airlines, but it can also increase the amount of airborne toxins, viruses and bacteria in the cabin. As 50% air is recirculated, with a tight air seal cabin, there is always a chance of spread of infection through air if any person is infected with airborne illness including COVID. However, few studies which have been done have shown that microbial contamination of cabin air entails a lesser risk of disease transmission aboard an aircraft than in any other public setting.[7],[8],[9] Low concentrations of bacteria and fungi have been found at levels that are not thought to pose any health risk usually lower than those found in other public places or in private houses. This is because most aircrafts have robust High-Efficiency Particulate Air (HEPA) filter systems. According to the Centers for Disease Control and Prevention, HEPA filters capture 99.9% of particles (bacteria, fungi and larger viruses or virus clumps) of 0.1–0.3 μm in diameter. Cabin air generally passes through the filters 20–30 times/h or once every 2–4 min. Besides that, ventilation systems on planes are set up in zones that cover between seven and eight rows, means air is shared between a small group of people in aircraft.[6]

While HEPA filters are effective in removing most of airborne particles, which include bacteria and viruses that are in clumps, but filters are ineffective in removing single viruses. Furthermore, the filters can become blocked and lose effectiveness if proper maintenance not done and changed as per manufacturer instructions.


  High-Efficiency Particulate Air Filters Maintenance Top


Every airline has what's called an operations specifications manual that dictates how that airline runs, including how often components are changed. There is some variation in how often they are to be changed. HEPA filters are made by various manufacturers, and each gives their own maintenance guidelines regarding cleaning and change of filter pads. It is important that these safety precautions are monitored regularly.

We may find people coughing and sneezing after a flight, in spite of air being cleaned. This may be due to dryness of atmospheric air at the altitude most aircraft fly. The airlines choose not to humidify the air because moisture can cause problems of its own, such as ice build-up in the space between the fuselage and the liner panels in the cabin putting stress on the aircraft. Virus survival in the environment depends on the amount of time it is taken to drying. Viruses would need moist environment and will become non-infectious if left dry. The aircraft dry air may be an advantage that even if one coughs or sneezes, droplets get dry up too quickly and are not infectious to others.

However, HEPA filter is not going to help if infection is from touching hard surfaces that have not been cleaned properly. When an infected person coughs or sneezes, they shed droplets. If these droplets fall on people or on surfaces and if touched with hands and then carried to nose, mouth or eyes with unwashed hands, a person can become infected. Hence, it is important that whenever chair handle, trays, overhead luggage cabin or toilet handle are touched, hand rub or hand washing is required.

In the aeroplane, air hostess spend maximum time with passengers, more so while distributing snacks. It is important that they are not infected and spent least time with the passenger in this COVID time.

Risk of catching airborne infection on a plane is lower than in many other confined spaces because of the filters and air exchange ratio, but the risk of COVID 19 infection is still possible through fomites. Hence contact precautions for example hand sanitisation and use face cover is advisable in air travel.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
World Health Organization. Constitution of the World Health Organization. In: Basic Documents. Geneva, Switzerland: World Health Organization; 1948.  Back to cited text no. 1
    
2.
SHRAE, Ventilation for Acceptable Indoor Air Quality; standard 62-2001. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers; 2001.  Back to cited text no. 2
    
3.
Available from: https://www.nationalgeographic.com/science/2020/01/how-coronavirus-spreads-on-a-plane/. [Last accessed on 2020 May 13].  Back to cited text no. 3
    
4.
5.
May Be Unhealthy (NPR Morning Edition: Cost-Saving Measure in Newer Airplanes News Broadcast; 30 July, 1993.  Back to cited text no. 5
    
6.
Anita Jean Smith, Cabin Air Quality in Aircraft: What is the Problem What is Being Done or what Can Be Done About It – Who Can Do It and How, Journal of Air Law and Commerce 61:Article 6.  Back to cited text no. 6
    
7.
Nagda NL, Fortmann MD, Koontz MD, Baker SR, M.E. Ginevan. 1989. Contaminant Measurements, Health Risks, and Mitigation Options.  Back to cited text no. 7
    
8.
Dechow M, Sohn H, Steinhanses J. Concentrations of selected contaminants in cabin air of airbus aircrafts. Chemosphere 1997;35:21-31.  Back to cited text no. 8
    
9.
Wick RL Jr., Irvine LA. The microbiological composition of airliner cabin air. Aviat Space Environ Med 1995;66:220-4.  Back to cited text no. 9
    




 

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