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The Importance of Indoor Air Quality in Veterinary Hospitals

Clean air is a basic requirement of life. The quality of indoor air, where people and pets spend a significant part of their lifetime, is essential to their overall health and well-being. The very buildings where they live and work, have long been associated with increased health risks and disease outbreaks in both humans and animals. As such, there is an ongoing debate as to whether indoor air should be regulated in the same way as drinking water and outdoor air pollution. Consider that in any given setting, one may choose not to drink the water or eat the food that is available, but generally has little choice in breathing the same air as everyone else. This makes air an environmental equalizer, with the potential to rapidly disperse whatever it may contain, including airborne pathogens. For example, canine and feline viral respiratory diseases, SARS-Covid-2 and influenza viruses can quickly spread in crowded and poorly ventilated indoor settings. Indoor pollutant sources can include dirt/dust/dander, contaminated surfaces, Heating Ventilation & Air Conditioning (HVAC) systems, building materials, furniture, drains, carpets, chemistries used for cleaning/disinfection/odor control to name just a few. This highlights the importance for improving indoor air quality and reducing the exposure to both pollutants and pathogens.

It is vital that veterinary hospitals implement strategies to improve the safety of indoor air as part of their overall infectious disease prevention and control protocols. Any facility where animals are housed are dynamic environments where the aerosol composition is complex and generated from multiple sources such as pets, humans, outdoor air, surfaces, drains and equipment. Controlling the concentration of indoor respiratory aerosols to reduce airborne transmission of infectious disease is key to keep occupants safe. This can be achieved by combining engineering controls such as: ventilation, filtration and air decontamination with other routine infection prevention measures.

Ventilation reduces the number of airborne pathogens by bringing in fresh air to ‘dilute’ the concentration of pathogens present indoors. Why is this important? An analysis of sick leave data for more than 3,000 workers found that 57% of all sick leave was attributable to poor ventilation.1

Filtration removes some of the pathogen load via passage of air through a special filter such as a HEPA filter, lowering the pathogens in the air and reducing the chances for pathogens to be inhaled. However, this is likely not enough since a study by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRE) showed on average that HEPA systems only capture ~50% of airborne particles in a room.

Today in the market there are two types of air decontamination devices: mechanical & electronic.

Mechanical devices are considered a passive system in that the particles must travel to and through the unit before being captured or inactivated. Filtration is an example of a passive process as air must pass through an appropriate filter to capture particulate matter and microbes. Most facilities already have a passive system in place within their HVAC systems by means of HEPA or MERS filters. Since the filters trap but don’t kill pathogens, care must be taken when changing out the filter. A spray bottle can be utilized to mist down the old filter while it is being gently removed and bagged for disposal. This will help prevent aerosolization of the particulate trapped by the filter. Appropriate personal protective equipment (PPE) should be utilized during this process. In addition to regularly changing out filters, the ducts should be routinely cleaned and sanitized.

Electronic air decontamination systems can include ionizers, photo catalytic oxidation (PCO) units, electrostatic precipitators, hydroxyl generators, devices with UV light components and other electronic air cleaning technologies. It’s important to keep in mind that these type if air decontamination devices could generate ozone.  Breathing ozone is harmful because it irritates the eyes, nose, and throat. It can cause chest pain, coughing, shortness of breath, and may trigger asthma attacks in those that are susceptible. Long-term exposure to ozone could cause chronic breathing impairments and compromise the respiratory defense mechanisms.

When purchasing air decontamination devices, it is critical to assure that they meet UL2988 certified ozone free and or CARB (California Air Resource Board) approved standards to guarantee the safety of the devices.

New generation PCO devices, release ions into the environment, these ions then combine with humidity in the air to and form an oxidizer that reacts with microorganisms in the air and on surfaces, thereby lowering the concentration of viruses, bacteria and fungi. Advanced PCO devices have shown to be over 99% effective killing viruses and bacteria, and over 95% effective against mold spores while also mitigating unwanted odors. They are safe, efficient and convenient. Furthermore, they are a cost-effective addition to the routine hospital infection control measures.

Ultimately the objective of air decontamination methods is not to kill all the microorganisms in a room, that would be sterilization, but to reduce the air microbial content and surface contamination to lower disease transmissibility. It is likely that different air decontamination strategies will have complementary and additive effects to make indoor air safer for animals and people

As more air decontamination devices become available, it is imperative to evaluate the safety and performance of each unit. Due to the complexities of indoor air environments and the assessment of microbial survivability, the evaluation of decontamination methods requires highly specialized equipment, technical skills, and test protocols. Look for testing performed in laboratories that utilize: General Laboratory Practices (GLP) standards; specialized equipment such as room size sealed aerosol chambers and microorganism surrogates that have similar resistance properties to the pathogenic organisms of concern. When purchasing devices, it is key to assure that laboratory testing for efficacy and safety has been done on the very model you are interested in. Avoid test results from ‘similar’ technologies or models and tests that were ran in small chambers with no proof that the units can cover the square footage they are rated for. Finally, be very wary of doing business with companies that are not openly willing to share the full test reports, only offer a summary of test results or provide results with missing or ‘blacked out’ information.

Investing to a create a healthy building is relatively inexpensive compared to the cost of spreading communicable diseases. Consider the ramification on your business reputation, potential legal and financial risks, and being able to attract and keep qualified personnel. Be prudent in researching the various options and choosing what will work best for your unique situation.


Authored by: Lucas Pantaleon DVM MS DACVIM MBA, Veterinarian Technical Advisor, Ogena Solutions

Chama Gomez RVT-R, BD & Technical Support Mgr., Ogena Solutions



1 Joseph G. Allen and John D. Macomber, “What Makes an Office Building ‘Healthy’”, Harvard Business Review, Digital Article published on, April 29, 2020, H05KFH.