HEALTHCARE FACILITY AIR QUALITY
A range of technologies for keeping hospital air ‘clean’
Dr Barend ter Haar, formerly a biochemist and research scientist, and director of BIOtAK, Healthcare Innovations Australia, and BES Healthcare, discusses some of the wide range of technologies available at a reasonable cost for maintaining good air quality in hospitals and other healthcare facilities, and for minimising the chances of airborne infection.
The last couple of years have concentrated people’s minds around infection prevention. The COVID-19 pandemic started with the public being asked to concentrate on this virus being contagious, and major concerns were around wiping down everything – from door handles to shopping – and leaving items for days for the virus to self-destruct. Steadily the advice changed round to treating the virus as being primarily infectious, being transmitted by airborne aerosol droplets, and subsequently, as a result, masks became mandatory. With the increased transmissibility of the Delta variant of COVID, there is greater emphasis on the need to reduce the level of infectious agents in the air, and come this autumn we expect that various bacterial and viral infections that have been less prevalent due to lockdown – infections such as flu, norovirus, colds, etc – will reappear in force as the herd immunity for these has decreased. To try to keep as many people feeling confident and safer at work (and away from their sick beds), we have even greater need to apply precautionary infection prevention principles, rather than belated rearguard infection control.
Figure 1: A simple air filtration system for close contact protection.
Technology for smaller spaces In this article, we will look at various types of technology applicable to smaller spaces, and compare them with what can be applied to larger spaces. The aim is to protect staff, as well as visitors, clients, and patients, as far as possible. The technologies range from the simpler level of air filtration, through more sophisticated systems which kill the bugs in the air, to those that cover surface disinfection as well, and, finally, those which break down the dead microbes into water and carbon dioxide. There are other benefits of air purification, depending on the system. Some will extract seasonal allergens such as tree or plant pollen, and others will remove airborne environmental pollutants, such as from road traffic. Some systems will also deodorise by oxidising
the chemicals responsible for creating noxious odours. Here we come full circle, since often the odours are the result of bacterial activity on fatty substances produced by humans in the first place, and thus getting rid of the bacteria removes the source of these odours.
Protection in smaller spaces Simple air filtration is at the lower end of the technological scale, but can be effective in small spaces, as long as the air from a contaminated source is not being dragged past uninfected people. There are many different types and grades of filters, and variations in the size of pores, and this will be reflected in their price. Simple filters may trap spore-laden dust, but the pores may not stop smaller items such as viruses. On the other hand, the
smaller the pore, the more quickly the filters will get blocked, and then the system becomes ineffective. Thus these systems are probably best for handling smaller enclosed areas, where people are meeting closely face to face, and where the air between people can be filtered (see Figure 1 for an example). These systems would be ideal to place between a member of staff and a patient in a consulting room, and are also great for first-line defence for staff at reception desks.
Filtration systems are also a good basic means of catching airborne allergens, such as pollen. The downside is that the filters need replacing routinely, and care should be taken in handling and disposal, so that any items caught in the filters are safely contained.
October 2021 Health Estate Journal 89
©Safe-air UK
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