As we head into winter, employers will need to consider factors such as the role internal heating and ventilation systems could play in spreading Covid-19 in indoor workplaces.
Features
Preparing for a Covid-19 winter
As we head into what may yet be the most challenging phase of Covid-19, the British Occupational Hygiene Society (BOHS), a charity focused on worker health protection through prevention, is set to step up its work to help businesses.
At the outset of the pandemic, BOHS was a ‘go to’ organisation to get guidance on personal protective equipment (PPE). With some of the world’s leading specialists in PPE counted amongst its members, that is hardly surprising. However, the Society continues to be concerned that a focus on PPE is problematic.
In the hierarchy of controls, which is at the heart of good occupational hygiene practice, individual protection, such as PPE, is the last line of defence. It signals that the workplace environment has been abandoned to the hazardous exposure and means the management of the risk is only as good as the availability of the PPE.

As we came to see in the first phase of the pandemic, PPE supply failures and a fundamental lack of scientific data on diagnosis, exposure and transmission of the virus made this a problematic approach.
Effective preventative strategies –revolving around distancing, physical hygiene and organising work in a different way – have had the impact that medical intervention could not have. The Society has continued to dissect and develop this risk-based approach, developing and promoting tools to assist with the complex task of determining how risk can be most effectively managed.
The Society’s occupational risk matrix launched this summer, brought together theoretical, scientific and social science knowledge to provide one of the most comprehensive tools for controlling workplace exposure to the virus. Its principles are being used by large organisations and have drawn interest and support from government as the unprecedented task of planning for an unknown future continues to challenge both private and public sectors.
By looking at data on infection rates and the nature of potential occupational exposures, the matrix enables users to focus on Covid-19 control measures by occupation, rather than just by location. A further development which brings in consideration of individual risks and vulnerabilities is under development.
As we head into the autumn, the Society has already turned its attention to the consideration of several important risk issues which arise from the maturity of the pandemic and the changing contexts for control. The summer, which provided much of the warm weather regarded as the means to help bring the pandemic under control, has departed and this leaves us with some practical problems.
For example, ventilation using outdoor air, so helpful in the summer, will potentially be less effective in exposure control during autumn and winter. Cold, moist air will not only be uncomfortable, but also potentially increase the possibility of infection or people getting exposed to masking illnesses like influenza which will make Covid-19 harder to detect.

Also, internal heating and ventilation systems have the potential to redistribute the virus, judging by emerging evidence that the virus is ‘airborne’. Much vaunted technical innovations, such as UV treatment of recirculated air, suffer from a paradox. The volume of air that needs to be recirculated means that air may not stay present in ventilation systems for long enough to enable most current UV technology to neutralise the virus.
The Society has been overwhelmed by developers promoting new systems and processes to address Covid-19. The pandemic has promoted rapid innovation, but many new technologies only work in principle and may have practical problems. For example, high volume ventilation systems may move a lot of air, but they might not move all of the air, particularly in locations in and around people – exactly where Covid-19 is likely to be present. Air testing equipment is beginning to become available, which may be useful in finding these locations of concentration, but might only provide a localised snapshot and can’t provide an assurance that all the air in all of a location is ‘Covid-19’ safe.
Autumn and winter challenges
Our expert group has identified some key issues that will need to be systematically addressed and considered by those who look after the health of workforces, when seeking to prevent exposure to or transmission of the coronavirus at work, as we head into autumn and winter. These include:
- Temperature, humidity and weather variations and the impact of these both on the virus’s ability to infect people and people’s susceptibility to infection
- Natural ventilation issues and the migration towards indoor work activities, as well as the use of temporary shelters in, for example, the construction sector
- Change in leisure activities and behaviours, including the return to face-to-face schooling, diminishing social distancing and reduced compliance with good hygiene procedures
- Change in occupational behaviours, arising from both financial pressures and the indirect impact of being forced to adopt additional control measures for Covid-19 – such as downsizing of teams, more gig working, less cash being available to purchase PPE and general weariness among employers and workers about the importance of following Covid-19 precautions
- Seasonal illnesses – such as colds and flu – and their masking effects on Covid-19 symptoms
- The increased likelihood of those who have contracted another illness experiencing complications if they also contract Covid-19
- Higher sickness absence rates and accumulated leave impacting the workforce
- Control measure attrition as other factors interfere with the effectiveness and appropriateness of them
- Viral mutation
- Seasonal working patterns bringing about new occupational infection challenges.
The Society feels that employers need to prepare for these challenges in a number of ways. The first is to look for lessons to be learnt and to continue to do so as the pandemic progresses. The second is to accept that, whatever a second wave brings, the public health and governmental response is unlikely to be the same as the concerted lockdown of the spring. It is likely that variable and local responses by national and local government bodies will require a different and more customised set of controls to be available for organisations to deploy to protect their workforces.
The critical question of the impact of test and trace, if it is deployed, and how any localised approaches might work, continues to be a challenge. With a constantly adapting approach to the management of the pandemic, keeping an eye on the range of potential responses by government remains crucial. This, in turn revolves around the evolving scientific knowledge.
Despite incredible efforts in moving the science forward, the debate is still open among scientists about crucial issues relating to the transmission and behaviour of Covid-19. In this context, the work of the Society will continue to focus on developing approaches which consider the potential risks and viable means by which they can be controlled, while ensuring that work and workplaces can continue to operate.
Behind all of this is a longer-term question. The physiological impact of Covid-19 means that those who recover may have permanently affected respiratory systems. This in turn leads to the prospect of a more fragile workforce, more vulnerable to other illnesses further down the line. The focus on preventing or controlling additional harmful occupational exposures to health hazards therefore becomes even more critical.
In many ways Covid-19 has exposed the fault lines in how we address occupational health challenges and the paramount importance of placing prevention at the heart of the occupational health agenda and health at the heart of every organisation’s health and safety strategy.
Professor Kevin Bampton is Chief executive officer at the British Occupational Hygiene Society (BOHS)
For more advice visit the BOHS website: www.bohs.org/coronavirus-hub
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