Air hygiene must be a focus for the travel ecoystem, says Preverisk’s Professor Rodney Cartwright and Dr Esteban Delgado
Another dimension has been added to the prevention of travel associated illness, or rather given more prominence, by the Covid pandemic. It has been recognised for centuries that infections can be spread through the air and that patients with certain diseases need to be isolated.
Initially the spread through the air was blamed on “vapours and noxious odours” before micro-organisms were recognised as the cause of infections. Improvements in public health infrastructure especially in the reduction of overcrowded living conditions were associated with the reduction of many infectious diseases.
The chief medical officer, Dr George Newman, in his introduction to the Report on the Pandemic of Influenza 1918-19 observes that “in coughing, sneezing and even loud talking the infections of influenza are transmitted through the air for considerable distances”, “on the importance of avoiding overcrowding and thronging of every sort” and that “well-ventilated rooms and open-air life afford some defence”. Recent experiences with the coronavirus have reinforced these observations.
What does this mean for travel?
What, however, are some of the implications for tourism? Many holidays abroad commence in overcrowded airports where social distancing, especially in pre-flight security check areas, can be minimal. Although most airports have good air conditioning aimed at making the environment comfortable, with regards to temperature and humidity, there is little known about ventilation and the dispersal of microorganisms.
On the plane there is usually close proximity to other passengers and cabin crew, although limited studies indicate that airborne transmission of infections such as influenza and tuberculosis suggests that any spread is within two rows of an infected person. Destination airports tend to have crowded areas at immigration points and luggage retrieval areas.
Much of a holiday is spent in a hotel with a crowded check-in desk, bars and restaurants. Most hotels will have air conditioning designed to ensure a comfortable environment but with little information or knowledge on air flow and refreshment. Opening windows often results in air conditioning units switching off. During the recent pandemic, laudable attempts have been made to encourage social distancing and encourage the use of ventilated areas.
Unfortunately there are no standards and guidance available for the ventilation of rooms and public areas. This contrasts markedly to the plethora of official guidance, statutory instruments and well researched studies for the control of food and waterborne infections. Official guidance for other aspects of health and safety are also available and together form the backbone for Abta’s Tourism Accommodation Health and Safety Technical Guide.
Guidelines on Indoor Air Quality (IAQ) have been produced by the World Health Organization (WHO) that give guideline permitted concentration values for benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons, radon, trichloroethylene and tetrachloroethylene. They do not, however, provide ventilation recommendations or standards for reducing airborne bacteria or viruses that would assist in reducing risks from respiratory infections. This is a problem that is only slowly being recognised as in need of study and official guidance.
Disparity between infection sources
The disparity between advice for the control of food and water borne infections and that for airborne infections has been highlighted and challenged in a peer-reviewed paper, “Prevention of community respiratory infection transmission: a new era must start now” by an international group of public health scientists and environmental engineers.
They pose the question as why such a disparity exists especially as respiratory infections are common and cause massive economic loss. Airborne infections are difficult to trace when compared to waterborne and food borne infections. Sampling requires specialised equipment, airflow patterns in buildings are complicated and little understood and the detection of viruses that are responsible for most airborne infections are in a different league to the commoner water and food borne bacteria.
As a result of the increasing recognition of the airborne transmission of Covid-19, the study of ventilation patterns in buildings and the means to control them has become an important field of study. It is suggested that in the future, ventilation rates must be risk-based and developed based on the assessment of the infection risk for each pathogen under consideration. Buildings are complex and have a varied use so that ventilation will need to be demand controlled and flexible. Research and development programmes are required with the results being applied in the design of new buildings.
This will, however, take some time and it will be necessary to develop interim procedures to reduce the risks of airborne infections. It should be emphasised that whatever procedures are undertaken to make the environment safer they do not in any way reduce the need for individual travellers to follow the advice of public health authorities on personal protection measures including vaccinations.
An initial step will be to undertake risk assessments considering the infecting microbe, how it spreads, the persons who may be infected and environmental factors. This will be a major task involving multi-disciplinary teams, in airports and other large buildings that may contain large numbers of persons.
The findings may well suggest the need to provide improved ventilation involving major refurbishment works. Such works would have major financial implications and are likely to require government involvement. There will also need to be full consultations to decide what are acceptable health risk levels before committing considerable funds.
Considerations for tour operators
For tour operators the major interest will be in accommodation units varying from small buildings with little or no environmental control to large complexes with rooms of differing sizes and environmental controls of varying complexity – but all highly unlikely to have been designed to filter or exchange air for the control of microbes.
The challenge is to design practical protocols and procedures within the present structures to reduce the risk of the transmission of airborne microbes to guest and staff. Experience has shown that the design of such protocols and procedures must involve hoteliers at all stages. Experts from outside the hospitality industry have made proposals in the past that theoretically look good and sufficient for the purpose but in practice cannot be implemented.
During the Covid -19 pandemic, Preverisk has been working closely with hoteliers to trial various proposals in order to develop guidelines that work in practice. It has been very apparent that it is important to keep changes as simple as possible and to try them out in different establishments, recognising that what may work in hotel A may not in hotel B. It is necessary to be flexible and ideally design custom-fit protocols and procedures for each unit. Ongoing monitoring and audits are essential components with the results considered by a multidisciplinary team that can rapidly suggest improvements.
It is also becoming apparent that what appear to be simple measures such as the use of plastic screens need to be properly evaluated, as there are suggestions that their use may have unexpected consequences. A recent assessment of the evidence on screens and barriers in mitigating Covid-19 transmission has been published by the UK Environmental Modelling Group.
A deep paradigm shift is needed
In summary, the importance of controlling the spread of indoor respiratory infections has been highlighted by Covid and as observed in the publication referred to above the paradigm shift we need is much deeper than simply rethinking how we design and operate buildings and transport; it must start at a much higher level than it did a century ago and needs facilitated by a multidisciplinary approach, not just public health physicians.
The development of air travel has enabled hundreds of thousand people to quickly reach destinations across the globe. At the same time it has enhanced the rapid spread of microbes so that infections that at one time were localised can now quickly evolve into pandemics.
In this 21st century, just as we expect the water coming out of our taps and the food we eat to be safe, we need to ensure that the air that we breathe in our buildings is clean with acceptable pathogen counts contributing to the occupants’ health.