How ACs May Be Spreading COVID-19 and What to Do About It

November 29, 2020
Written by HVAC Link

At the beginning of 2020, the world was rocked by the outbreak of the COVID-19 pandemic. Suffice to say, the magnitude and scope of the disease are unprecedented. While a significant portion of the nature of this virus remains unknown, we know for certain that it is highly contagious and airborne. Because of that, people are advised to stay indoors and limit social interactions as much as possible.

However, even indoor spaces aren’t completely safe. The coronavirus can spread inside buildings as well — whether it’s in the home, office, or school. Evidence points toward the role of air conditioning. So how does air conditioning spread the virus and what can be done about it?

How Air Conditioning May Be Spreading the Virus

Several viruses, including the COVID-19 virus, are airborne. At present, health authorities acknowledge three ways for the coronavirus to spread:

  • Transmission via droplets from speaking or coughing
  • Transmission via contaminated surfaces
  • Transmission by aerosols that remains in the air for extended periods

Initially, the World Health Organization (WHO) did not consider aerosol transmission as a cause of infection. However, a Chinese study has detailed a case where 10 diners contracted COVID-19 despite their socially-distanced tables. Similar cases were subsequently observed in the US and Spain. The results suggest that the virus may not be have been passed via large droplets as they quickly fall out of the air. Instead, the aerosols or “micro-droplets” could have been brought table-to-table by the “strong airflow” from a mounted air conditioner.

Experts explain that aerosols or the tiny particles expelled by an infected person can then be inhaled by another. Aerosols are incredibly tiny, measuring less than 100 micrometres. They are so light that they can remain suspended in the air for hours.

While the studies are not definitive, patterns of the outbreak in bars, restaurants, schools, and other indoor establishments prompt the need to rethink what people know about the virus and the necessary steps to take to prevent further infections. Global authorities have since set out new guidelines about possible indoor infections, especially for people who spend most of their time inside crowded and poorly ventilated areas.

How to Prevent the Virus Spread

The possibility for the virus spreading indoors is true both for residential and commercial establishments. While the rate of virus infection can significantly be reduced by a half just by wearing a mask, the dynamics of aerosol transmission must still be understood and resolved. So, how can you keep your home or business clean and virus free?

Surprisingly, the answer could also be your HVAC system. Heating, ventilation, and air conditioning systems are more than capable of circulating and processing large volumes of air that could potentially reduce the risk of exposure and contamination. Here are 5 ways to curb the spread of the virus:

Improve Air Change Rate

Experts recommend opening up indoor spaces and letting fresh air in regularly to remove any virus build up inside your building. The belief is that the virus cannot survive outside since the UV radiation from the sun can kill them almost instantly. For this reason, it is advised that increasing the outside air coming in to flush out the indoor air dilutes and eradicates the virus inside the space faster. Just opening up the doors and windows can already improve the air change rate significantly.

This could, however, be difficult for bigger commercial or office buildings. Fortunately, there are air handling units that can improve the air change rate in your building. Your air conditioning system can potentially help combat the virus by facilitating better and correct ventilation. If you are worried about wasting energy, newer HVAC systems also have energy-saving features while operating. The change-over can occur several times within a small amount of time, and in approximately 20 to 30 minutes, your indoor air can be renewed completely, dropping the risks tremendously. 

Manage Air Flow Patterns

As the studies continue to evolve about how coronavirus spreads in the air, the role of airflow patterns is widely recognized in minimizing transmission. Researchers speculate that a high-speed airflow past a carrier to others have a higher chance of spreading the virus across the room. Besides improving the air circulation from outside the building, home or business owners can reconfigure their ducts to manage airflow.

After a study by the World Health Organization with restaurant layouts, seating arrangements, and air condition inlets and outlets, 3 main principles should apply in airflow management:

  1. Change airflow patterns to encourage vertical laminar airflow – direct air from the ceiling to the floor – rather than a turbulent airflow.
  2. Air speed must be slow and steady.
  3. Direct the flow of potentially contaminated indoor air out of the rooms and away from people.

Building managers must take into account the number of occupants, room architecture, and furniture placements when managing airflow. To realize how air conditioning can prevent the spread of the virus, you can upgrade or add air outlets in HVAC systems. Suspended outlets from ceilings can be replaced with covers to produce laminar flows instead of mixing and distributing air. Likewise, you may also want to either add or remove physical barriers or partitions, depending on your space, to adjust the direction of the airflow.

Increase Levels of Air Filtration

or added protection, adding a higher level of filtration to your air conditioning may increase the effectiveness of preventing the spread of disease. While it is unknown how filtration would impact the virus given the many other unknowns surrounding it, an air purification option in your HVAC system is still beneficial to health in general.

Several technologies can purify the air, including filtration, irradiation, and thermal sterilization. These can be incorporated into your system and help remove viruses and bacteria. Among these options, filtration is the most common method. Filters can be installed at the air inlet or outlet of the air-handling unit. Their fibre can trap particles that are too large to pass through the openings. Not all air cleaners, however, are equal, and each has different capabilities. They are rated based on their efficiency in filtering particle sizes.

The Minimum Efficiency Reporting Value (MERV) are given ratings according to the size of particles they can filter:

  • MERV 11-12 captures 65 to 80% of particles with size 1 to 3 microns, such as lead dust and vehicle emissions.
  • MERV 13-15 captures 50 to 85% of particles 0.3 to 1.0 microns in size, including smoke and exhalation droplets.
  • MERV 16 captures 90% of particles measuring 0.3 to 1.0 microns. Both MERV 13-15 and MERV 16 filters are usually used in general surgeries and smoking lounges.
  • HEPA Filter is the most effective in removing viruses and bacteria from the air. It can capture 99.7% of particles 0.3 microns in size.
  • Monitor CO2 Levels

Carbon dioxide (CO2) levels are an effective indicator of air freshness in your home or business. The higher the CO2 concentration, the older and staler the air. The explanation for this is simple. As we breathe, we inhale oxygen and exhale carbon dioxide, and without air circulation, CO2 can get increasingly dense inside. Since the virus can be transmitted as you expel air, a higher CO2 level may mean a higher chance of COVID-19 exposure.

A CO2 level monitor can help you keep an eye on your air quality and know when you should open the doors and windows to get some fresh air inside. The good thing about CO2 monitors is they can easily be purchased from any home improvement stores and can be installed pretty quickly.

  • Upgrade HVAC Systems

HVAC systems are especially vulnerable to the virus and can also propagate its spread. Nevertheless, the correct way of using these systems also factors into preventing the worst-case scenarios from happening. One way to ensure that you get the best result from your HVAC system is to make sure that it is up-to-date and working perfectly.

For older systems, technicians may recommend an upgrade to maximize your control over air purification, ventilation, and airflow management. Install variable-speed motors to control airflow and add high-performance purification systems or filters to keep the virus from floating in.

As the world continues to grasp the effects of the pandemic, it is important that you keep your home or business safe in every possible way. Start with your air conditioning system. Turn what could be a liability into an asset.

HVAC Link service residential and commercial clients, including doctors, schools, and restaurants. We can assess your airflow and air exchange and provide HEPA solutions to your system. Keep yourself safe. Call us at (416) 567-3498 now.

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