What you need to know about Indoor Air Quality and The Fourth COVID Wave

The Fourth Wave

Indoor Air Quality (IAQ) and COVID-19 are inextricably linked. Having a properly engineered HVAC system is crucial to reducing viral particles within buildings as we return to work – especially with the fourth wave of COVID-19 upon us.

We have been hearing a lot lately about a fourth wave of COVID-19 which may be starting at this moment. If this happens there are two main questions that need to be answered:

• Will the next wave be worse?

• What can we do to protect ourselves?

To answer these questions, we must first understand why a fourth wave is possible and how it will affect vaccinated and unvaccinated people.

How is a fourth wave possible?

As of August 1st, 2021, 28% of the world’s population has received at least one jab and 14% are fully vaccinated. In Canada 59% of us are already fully vaccinated and while in the USA 50% are fully vaccinated.

World Vaccination Drive

What we do know is that getting fully vaccinated gives a very high level of protection against known COVID-19 variants and causes some protection against the known COVID-19 variants.

To date there are four known variants of concern including the B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma): and the B.1.617.2 (Delta). These variants are the result of the virus mutating in people who carry the disease. Although initial research has shown that vaccinations do provide protection against these variants, it is not known how protected we are against the variants of these variants.

The possibility of further mutation is very likely as 86% of the world population are not protected against known strains of the virus and 100% of the world population are not fully protected against unknown strains.

COVID-19 Mutates

Unless we can get the world population vaccinated in a very short period of time, the virus will continue to mutate resulting in variants with worse effects and variants with little effects. In general, all variants will have the potential to create another wave of virus transmission as we are currently seeing with the Delta Strain.

Will the next wave be worse?

It is difficult to tell, but through science we are learning more about virus transmission and how to use existing technology to combat virus spread.

Since the spread of COVID-19 is more apparent indoors than outdoors, we must look at what can we do to reduce the spread indoors.

Wearing masks is likely here to stay

This can be accomplished in various ways using existing technology. Basic measures include:

• Wearing masks

• Hand sanitizing

• Social distancing

• Vaccinations

• Contact tracing

• Building HVAC controls

I predict that each new wave has the potential to be worse than each previous wave due to mutations and lack of vaccinations. To reduce the potential for a worse wave we need to implement as many layers of control as possible and increase our vaccination rate worldwide.

In order to increase world vaccinations countries with high vaccination percentages such as Canada must share their vaccines with other nations that do not have the resources to purchase the vaccines required to protect themselves.

However, this will take time and may not fully reduce the transmission of COVID-19.

Countries need to share their vaccines

What can we do to protect ourselves: Indoor Air Quality (IAQ)

Proper Indoor Air Quality is good protection against COVID-19

Since we are more likely to catch a virus inside than outside the controls we use should attempt to recreate outside air conditions as closely as possible. This can be done with the following Indoor Air Quality controls:

• Airflow Patterns

• Relative Humidity

• Air Change Rates

• Filtration and Ultraviolet Rays

Once these measures have been implemented, ensuring compliance with industry standards, the best possible Indoor Air Quality conditions will exist to reduce the spread of COVID-19 and its variants.

Airflow Patterns

The science of airflow patterns and virus transmissions is a relatively new field. Building airflow patterns are modelled and then used to predict the transmission of virus particles.

The key to airflow pattern controls is to ensure airflow patterns are reduced as much as possible in our breathing zones.

One possible solution is to install supply diffusers at a high level and install low level exhausts. This results in a reduction in contamination at the breathing zone in some cases.

A model of high level diffusers and low level exhausts

Humidity Controls

Relative humidity controls between 40% and 60% significantly reduce the infectiousness of COVID-19 and increase our body’s resistance to the virus.

However, in northern climates, such as Canada, increasing a building’s relative humidity can cause an adverse effect: unwanted mold growth. To combat this, a building’s relative humidity should be increased without causing the building to sweat.

Under certain conditions where this can not be maintained, a building’s control system should include an alarm to instruct the tenants to wear masks. This causes a micro climate to occur within the mask and increases its high relative humidity.

As a result, this helps combat the spread of COVID-19 by creating favorable indoor air quality conditions at our breathing zone.

Relative humidities where certain airborne particles flourish

Air Change Rates

Dilution of viral particles has been used for a long time to increase a building’s Indoor Air Quality. It’s also a great measure to determine a building’s effectiveness in diluting a building indoor air space in the event of a contaminant.

Typically, changing the air in a room 6 times per hour (6 ACH) is the most cost effective way of diluting indoor air.

It takes 69 minutes to dilute 99% of the contaminants within a indoor space after the contamination source has been removed. An example of a contamination source could be a person infected with COVID-19.

Air changes per hour and time to contaminant dilution

Filtration and Ultraviolet Rays

Filtration and ultraviolet lighting (UVC) are another layer of control that can be implemented to increase a buildings Indoor Air Quality.

This strategy when installed locally can condition the air within a building space to both disinfect any airborne viruses and filter anything that attaches to dust particles. Under proper conditions in combination with a HEPA filter, this can cause a 99% reduction in the spread of COVID-19.

UV lighting offers more protection against contaminants

What now?

If COVID-19 continues to mutate and new variants continue to emerge, the virus will continue to be a threat to our health.

We have little control over the spread of mutations or how effective our existing vaccines are against any new variant.

But by implementing the discussed Indoor Air Quality controls , we can significantly reduce the probability of infection within our restaurants, hotels, factories and any other building requiring a safe working environment.

The fight is far from over against COVD-19 and its future variants of concern, but using science and HVAC engineering, we can improve our indoor air quality to reduce our chance of infection within our buildings and keep our loved ones safe.