Clean air in hospitals

Tuesday - 13 August 2019

If you were asked to name a clean building, there is a good chance that you would think of a hospital. And you would be correct. The need to be clean is ingrained into every part of everyday hospital life. But there is a flipside to this; hospitals are normally sited where people are – in built-up, urban environments surrounded by good transport links. Unfortunately, with these conditions, high air pollution normally follows.

And that poses a problem for hospital managers. How do you protect people who are at their most vulnerable, when you are operating in an inherently unclean environment? And how do you control the transmission of infectious contaminants and dirt inside your building too? The answer lies in the hospital ventilation system. Or more precisely, its air filters.

The threat of outside air pollution

The health effects of breathing polluted air are well known. Numerous studies have linked particulate matter (or PM) to health issues including heart disease, chronic lung disease, asthma and lung cancer – as well as less obviously-related conditions, such as osteoporosis, diabetes, Alzheimer’s and dementia.

Just like bacteria and viruses, PM poses the most immediate danger to infants, the elderly and the sick. But due to these broad range of health complications, patients and staff in all wards and departments are at risk. So while certain areas of the hospital will need higher levels of air quality, it is important to protect the building as a whole from the harmful effects of air pollution.

The benefits of improving air quality extend beyond patient welfare to include staff performance too. REHVA (Federation of European Heating, Ventilation and Air-Conditioning Associations) investigated the link between air quality and productivity. It found that poor air quality and elevated temperatures consistently lowered performance by up to 10%1. Another study by Harvard University discovered that doubling ventilation rates in a clean indoor environment increased cognitive performance by more than 100%2. In a hospital, budgets are tight and problem-solving is a matter of life and death. So a poor environment where staff are unproductive, or unable to think quickly and clearly can have serious consequences.

The danger of microbial contaminants

When it comes to contaminants generated internally, the main worry of a hospital is the transfer of infectious diseases across the building. The wellbeing of patients, staff and visitors depends on preventing germs from proliferating and spreading.

Whether it’s planned for – in the case of wards treating patients that have been admitted with an infectious disease – or unplanned for – as in the case of an outbreak, controlling the spread of microbial contaminants is crucial. From a cost perspective alone, an outbreak of infection can cause longer lengths of stay, missed elective surgical revenue, wasted staff time, bed or ward closures, as well as additional contact precautions.

In sensitive areas, such as the operating theatres, recovery or oncology wards, air quality requirements are even higher. Patients undergoing open-wound surgery or with immunosuppression need cleanroom-quality air to provide protection from infection.

Other contaminants generated indoors

Cleaning is an integral part of daily hospital life – impacting every area and action in a healthcare facility. But cleaning products themselves emit a range of volatile organic compounds that are harmful to human health. Ethanol and ammonia are commonly found in disinfectant agents, and formaldehyde in laundry detergents. As these products are used in such large quantities within a hospital, the impact on patients, visitors, and in particular, staff is potentially very high. That is why cleaning agents are thought to be one of the leading causes of occupational asthma among healthcare workers.3

But hospitals aren’t just about the wards. There is a host of support operations helping the hospital function – many of which can also contribute to poor indoor air quality. Odors from kitchens or waste disposal can be unpleasant, while fumes from emergency power generators can be dangerous. And remedial works can cause dust and paint fumes across the hospital.

What can you do?

Whether contaminants are generated indoors or enter the building from outside, the key to protecting patients, staff and visitors is the air filtration system. Given this importance, it’s crucial that the filter system is both configured correctly and well maintained. Here’s a few ways to do that.

Review your requirements

Just as the level of pollutants varies across a hospital, so too does the required level of air quality. So it’s important to think carefully about the filter system throughout your healthcare facility. Under specifying the air cleanliness poses a risk to building occupants, while over specifying the filter class can lead to higher purchasing and energy costs.

We recommend working with your filter partner to review the required and actual air quality in each area of the building. This review should include both supply air and the extract of contaminated air. Once you have this information, a filtration system can be devised that enables you to reach your defined air quality goals while minimizing expenditure.

Look after your ducts

Duct cleaning can be a long and laborious task, particularly in older hospitals where retrofitted ventilation systems can be complicated and difficult to access. But it’s an important task nonetheless – the warm, dark and damp conditions of an air handling unit make ideal conditions for mold and bacteria. Any contaminants lining the ducts before the filters can compromise the life and/or performance of the filter system. While contaminants and bacteria after the filter stages will be gradually swept into the indoor environment.

Regulation varies from country to country, but there is likely to be guidance on the timing and type of duct cleaning that you must perform in a healthcare facility. So, ask your filtration partner for help to ensure that you stay compliant.

Boost surgical performance

When it comes to the operating room, an air delivery system must provide reliability, flexibility and performance above all else.

If identified quickly, a filter failure in most areas of the hospital will result in a mess to clean up and a minor deterioration in the indoor air quality. In an operating theater, a failed filter can have life-threatening consequences. So, only select filters that come with bulletproof quality assurance and are stringently tested to internationally-accredited standards.

Today’s operating rooms need to be flexible to the needs of the hospital without causing distraction or discomfort to the OR team. So, if you are retrofitting an existing theater or constructing a completely new operating room, specify a laminar flow ceiling that will wash contaminants away from the patient without causing a draft for the OR team. And also look for a ceiling system that will enable you to swap, move or integrate fittings – such as media bridges, surgical lights and ceiling pendants – seamlessly. The ceiling system is there to help the OR team do what it does best.


1 REHVA Guidebook: Indoor Climate and Productivity In Offices, 2006

2 Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers, Harvard University, June 2016