How can we minimise the risk of airborne infection in hospitals and at home?
On average, people in the UK and much of Europe spend around 90% of their time indoors – and few are aware that the air they breathe inside their homes, workplaces, shops and other indoor settings can be up to five times more polluted than the air outdoors. Indoor air pollution can include dust, mites, dander, mould spores, volatile organic compounds (VOCs) and pathogens: common infection agents, which are of particular concern in clinical and hospital environments, including Staphylococcus, Streptococcus and Enterococcus species; variants of pneumonia; and – as a relatively recent but significantly more virulent example – COVID-19.
Clinically significant microorganisms can be introduced into healthcare settings via a number of exterior sources, including people, water, construction materials and air currents. The introduction and spread of airborne bacteria, viruses and fungi within hospitals may be attributed to poorly maintained heating, ventilation or air conditioning systems; open windows and doors; ceiling insulation and false ceiling spaces; and air filters, among other vehicles.
At-risk patient populations
Certain patient demographics are particularly vulnerable to airborne infection, either due to compromised immune systems – as in the case of elderly patients, those undergoing chemotherapy, or patients with HIV – or due to risks associated with a patient’s occupation, lifestyle or limited access to medical care. At-risk groups in this second demographic may include drug users, members of medically underserved communities such as homeless or immigrant patients; and health and care workers, who are more likely than most to come into contact with infected people, surfaces or air for sustained periods of time.
Optimising air quality to minimise risk
The airborne transmission of harmful microorganisms may be arrested and mitigated in a number of ways. One of the most crucial ways to halt the spread of infection through contaminated air is the implementation of frequent, comprehensive, consistent cleaning and disinfection protocols for all air conditioning, filtration and ventilation systems, which represent a significant risk factor for indoor transmission of disease.
The US Centers for Disease Control and Prevention (CDC) draws particular attention to the risks posed to hospital air quality by construction and renovation activities, which may disrupt or dislodge dirty or contaminated materials; cause or exacerbate water leaks which contribute to a hospitable environment for fungi; and compromise the free flow of air through fan or ventilation systems. The CDC therefore recommends enhanced caution when planning construction within hospital settings, stating: ‘Construction, renovation, repair, and demolition activities in healthcare facilities require substantial planning and co-ordination to minimise the risk for airborne infection both during projects and after their completion.
‘Environmental services, employee health, engineering, and infection control must be represented in construction planning and design meetings should be convened with architects and design engineers.’
Indoor air should be regularly sampled, monitored and analysed for signs of contamination and disease transmission.
Monitoring and purifying indoor air
Air purifiers have come a long way since their inception; and modern air cleaning technology is now more than sufficient when it comes to providing optimal indoor air quality. A multitude of air purifier types are available; perhaps the best known of the group is the HEPA (high efficiency particulate air) filter. Developed during World War II to eliminate radioactive toxins produced during atomic bomb creation, the HEPA is still the most efficient type of air filter available. They are made from fibreglass and specialise in eliminating dust, mites, pollens, mould, pet dander, bacteria and 99.97% of common allergens.
Activated carbon (AC) filters use adsorption technology. Not to be confused with absorption, adsorption refers to the adherence of atoms, ions, or molecules (from gas, liquid or dissolved solids) to a designated surface. AC filters specialise in trapping chemical fumes, odours, gases and smoke. Ionisers and ozone generators are also examples of modern air purification technology. Although they do not boast the same impressive rate of efficiency as the HEPA or the AC filters, they work proactively; meaning unlike HEPA and AC, they do not rely on fans to operate.
Home automation technology for purer air
Smart technology is becoming increasingly affordable. One of the latest smart technology trends, home automation, can now be utilised to monitor and improve the quality of air in the home using an existing HVAC system and a whole house purifying system. An automated indoor air quality monitor allows users to view data on their phone in real time, as well as past measurements and events.
When the system receives a bad air quality report from the monitor, it can trigger the activation of fans, adjust humidity and boost airflow, sending clean air back out through all of the HVAC supply vents in the home. In addition to purifying the air, a smart thermostat and air purifying system reduces the amount of energy a home uses, ultimately saving the homeowner money.
This article is from issue 14 of Health Europa. Click here to get your free subscription today.