How HVAC Affects Viruses

With the current COVID-19 Pandemic it more important than ever to understand how HVAC affects viruses and other indoor environmental issues. Indoor air quality is something that many building occupants don’t give much thought to until it impacts their comfort, but IAQ is a critical part of building engineering and maintenance. A building that is not heated or cooled properly or has humidity levels that are not maintained makes it harder for employees to work effectively.

Poor IAQ can also affect the health of workers. A well-designed HVAC system that is serviced and maintained with controlled humidity levels limits mold, dust mites, and bacteria throughout the building. More importantly, it limits the spread of viruses.

Maintaining Relative Humidity

Maintaining relative humidity is an important part of controlling the amount of particulate matter that circulates throughout buildings. Relative humidity (RH) is expressed as a percentage representing the amount of moisture in the air compared to the maximum amount that could be present at a given temperature. Warm air holds more humidity than cold. The EPA recommends a relative humidity level of under 60 percent at a minimum. An ideal RH level for IAQ is between 30 and 50 percent. When the relative humidity is kept within this range there is a decrease in biological contaminants such as bacteria, animal dander, dust mites, and pollen. Viruses such as those that cause colds, the flu, and severe acute respiratory conditions like COVID-19 are also limited by maintaining proper RH levels.

Understanding how HVAC affects viruses gives building engineers and managers an edge in their efforts to limit their spread. Outdated components and dirty coils and vents make it harder for HVAC systems to keep the air free of contaminants. Water intrusion in the building also raises humidity levels. This could result from water damaged building materials, pooled water from leaks, and flooding after periods of heavy rains. Increased moisture levels allow mold and mildew to grow and also dust mites which are an allergen for many people.

Reducing Viral Infections

Viral infections are more likely to occur in cold, dry weather. Low humidity levels allow these airborne viruses to stay in the air longer. Low humidity also dries out the mucous membranes in our respiratory systems making us more prone to infection. An example of how humidity affects the spread of viruses is The Centers for Disease Control and Prevention (CDC) study on how low humidity affects viral flu infections. The study found that at 23 percent humidity, between 70 and 77 percent of flu virus particles stayed active an hour after being released into the air. At 43 percent relative humidity, that number dropped to 14 percent.

People spend more time indoors during colder months and this close contact allows the virus to spread from person to person quickly. This makes the need for top-performing HVAC systems a priority for building and facilities managers.

Consequences of Poor IAQ

The results of poor IAQ are low worker morale, loss of productivity due to missed work, serious illness, and in some extreme cases, death. The human toll is the most important issue, but for a business owner, the financial health of their company is crucial to their ability to take care of employees. Poor IAQ leads to Sick Building Syndrome (SBS), a condition where building inhabitants feel unwell. Their symptoms of congestion, throat irritation, and headache disappear once they have left the building. Over time, the performance of HVAC systems decreases due to dirt or as a result of not being maintained. This contributes to SBS and impacts occupant health.

How we Help

Occupant well-being is a priority for building managers and engineers. That’s why the Pure Air HVAC Hygiene Assessment lets building stakeholders know the impact their HVAC system has on Indoor Air Quality. The evaluation identifies mold, allergens, moisture, and records temperature and humidity levels. A report is given detailing recommendations for remediation.

We also have specialized decontamination and touch-less disinfection protocols that are engineered for COVID-19 response. Especially tackling how the HVAC affects viruses like SARS-nCoV-2.

Contact Pure Air Control Services with questions about the HVAC Hygiene Assessment or to schedule a complete Building Health Check. Call 1-800-422-7873 today or email us here.