Breathe easy: maintaining clean air in a veterinary practice

Biosecurity for both your staff and clients is an essential requirement during these difficult times.

All environments we work and live in will have a degree of contamination, and a susceptibility to particles, moulds, bacteria and viruses.

With normal routines of thorough cleaning and the use of disinfectants, combined with the procedures that are undertaken to maximise biosecurity, we can feel pretty confident of this as we can see exactly what we are doing. For example, how medical waste is now routinely disposed of in a safe way that protects staff and clients.

The presence of airborne particles can produce a different hazard, as COVID-19 has shown during the past 18 months.

Modern technology has now allowed the development of mobile, high-quality air filtration systems that can minimise the presence – and reduce the associated risks – of airborne contaminants such as viruses, bacteria and physical particles.

Filtering surgery air is the final part of the cycle when it comes to clean air; the essential basic first steps are to minimise the sources of contaminated air before it becomes airborne through thorough cleaning and disinfection of areas.

However, external factors that will produce air pollution within practice buildings will enter via doors, windows, air circulation systems, and via humans who can carry and transmit virus particles. Both external and internal examples from within the buildings that will produce contamination can be seen in Table 1.

All of these can produce both short-term and long-term health problems if left unchecked.

The effects of these factors show through when too little air is entering the building, allowing pollutants to accumulate to levels that can cause problems.

These can be dealt with by mechanical ventilation systems, which are fine unless the source is originating from outside the building as this will then effectively result in the system actually spreading the contaminant around – unless it has been filtered out.

Exchange rate

When we allow outdoor air to enter a building, say through open windows or doors, the rate at which outdoor air replaces indoor air is called the exchange rate. The lower it is, the greater the chance of pollutant levels increasing.

Among the most serious airborne risks to any health worker is that of transmitted virus and other living particles within the air space of a building. COVID-19 is classical of this by spreading the viral particles of an infected person within the aerosol droplets when they cough or sneeze.

Ensuring air purity

When looking to control airborne diseases the essential first steps are quite basic:

• Thorough and regular cleaning of premises, including floors, walls and ceilings. Removing the contaminants with powerful good-quality vacuums.
• Using recognised disinfectants and antiseptics to kill microorganisms.
• Ensuring staff clothing is always clean to minimise contamination.

We then need to look at how we can ensure air purity by utilising new technological air purification systems (APS; Figure 1).

What do you need from an air purification system for a veterinary practice?

You will be looking to minimise the presence of particles such as dust, pollen, house dust mites, faeces, dander and spores. These could affect any staff member who suffers a degree of asthma.

You need to reduce the challenge of viruses and bacteria, such as COVID-19, common cold, flu and some airborne bacterial infections.

To improve the quality of your staff’s working conditions and clients’ comfort, you should look to reduce smells.

Huge range

The biggest handicap of purchasing a built-in system is the cost and disruption of fitting; however, with improved technology, high-quality mobile systems have now become available that can offer the level of performance a vet practice requires.

The market will offer a huge range of types of “air purifiers”. A flashing red or green light on a nice-looking piece of equipment can give a false sense of confidence that what you have bought is actually doing what you need.

However, like a lot of equipment of this type, you cannot easily check exactly what it is doing, and without air sampling you have to rely on the information you have been given at the time of the purchase.

To understand what you will need, look at the size in microns (µm ) or nanometres (nm) of the particles we are dealing with (Table 2).

SARS-CoV-2 virus has been found to have a diameter of between 50nm to 140nm ¹, while the dust mite is 2,000 times larger (Figure 2).

So, what should you be looking for in an air filtration system (AFS)?

[1] The system should have multi-filtration, which would include:

[a] Prefilter to remove larger particles, such as dust, hair or skin flakes.

[b] An adenosine triphosphate high-efficiency particulate air (ATP-HEPA) antimicrobial peptide filter that removes particles with a diameter of 2.5µm.

[c] High efficiency carbon filter – this will absorb harmful substances, for example mercury and benzene.

[d] UVC ultraviolet bulb – to kill viruses and bacteria.

[2] The system should be fully automated and able to detect and display the level of particulate matter in a room – this will give an indication of the air quality. This is measured in µg/m³ – for household and commercial air, a level of 12µg/m³ to 25µg/m³ is considered normal. For hospital and veterinary premises, a lower level of 6µg/m³ to 12µg/m³ is advised.

A filter is generally classed a “True” HEPA medical filter (HEPA H13) if it filters out more than 99.7% of particles above 0.3µm in diameter. These high-density ATP-HEPA antimicrobial filters will remove airborne particulate matter with a mean diameter of 2.5µm. This is opposed to many other filters that have HEPA filters that only capture down to 2.0µm. Filters labelled “True HEPA” are tested to a level of high efficiency. HEPA-type filters can have a comparable performance of air change, but their efficiency of removing particles can vary.

[3] The system should be designed to have a 360° air intake to maximise the amount of air that is taken in to be circulated.

[4] It must have enough power to undertake the required number of air changes in a room. In a commercial environment, 6 air changes per hour is acceptable, but for a medical environment we expect 10 changes per hour. An air purification unit should be able to purify 600m³/hour.

[5] The system you purchase should be able to show the scientific backup behind any claims that are made.

[6] Deciding on how many APS units you may require is dependent on the sizes of the rooms and the volume of people using it. For example, a prep room may have 3 to 5 times the staff working than say in the kennels or the practice offices at any one time. If you were to suggest in line with this requirement, it would be a matter of one unit per relevant room in a typical sized vet practice.

[7] Costs – for professional medical standard units will cost around £700 to £900 for a quality APS.

Hopefully this article will help you know what to look out for, so rather than rely on the flashing light, ask for some science behind the light.