Indoor air quality (IAQ) as a wellness factor has gained more prominence since the global Covid-19 pandemic started in China. The EPA has revealed indoor pollution can be 2-5X higher than outdoor pollution, and ranks indoor air pollution as a top 5 public health risk. As schools, offices, and retail businesses reopen, the state of indoor air quality and proper ventilation presents a major challenge in curbing the spread of Covid-19.

Homeowners, office managers, and school administrators have a lot to do to improve indoor air quality (IAQ) in their properties. Two factors that will play a significant role in fighting Covid-19 in this situation are ventilation rate and air change.

This post delves into these two air quality concepts to help property owners and business operators fight Covid-19 more effectively.


The Risk of Covid-19 Infection in Enclosed Spaces 


With the pressure to reopen the economy, most states have relaxed Covid-19 rules. Schools and businesses have started reopening even with reports of a second wave of the pandemic.

WHO says there is a big risk of airborne transmission of the new virus through small respiratory aerosols in addition to contact and droplet transmission. When people talk or breathe, they release these respiratory aerosols, and which stay suspended in the air and build over time.

If you have students or workers in poorly ventilated indoor spaces, there is a great risk of exposure to the novel virus.


What is Ventilation Rate and Air Change in Indoor Air Quality (IAQ)?


Whether you are preparing to reopen your school, office, or business, it is important to appreciate the lurking danger of having people in an enclosed space. The two factors that can help you reduce the risk are:

·         Ventilation Rate: This is defined as the rate at which external air (fresh air) flows into the building. In terms of air. In other words, it is the volume of outside air flowing into a room per unit of time.

·         Air Change: This is the number of times the air enters and exits a room from the HVAC system in one hour. It is also the ventilation rate of a room divided by the volume of that space. Air exchange per hour (ACH) refers to the frequency of air change in an hour. A higher ACH is important in reducing the risk that of disease spread as any viral particles are removed per cycle. Amidst the covid-19 pandemic, this is a critical consideration for building owners seeking to allow more people into their properties.

These two factors determine how well you can protect occupants in a room from Covid-19 infection by keeping the room ventilated. However, understanding ventilation rate and air change is only the beginning. The application of these metrics in your indoor space requires constant monitoring and tracking. As schools and offices reopen, property owners need new tools customized to focus on these factors. 

When you promote fast air exchange, there is a reduced risk of respiratory aerosols and other contaminants remaining in the air.

For most HVAC systems, one cycle brings in about 20% of fresh air while recirculating 80% of fresh air in the room. Research has proven that boosting ventilation can reduce the transmission of airborne diseases. There is increasing body of finings that prove well-maintained heating, ventilation and air conditioning (HVAC) systems have a big role to play in reducing the risk of potential airborne transmission of SARS-CoV-2.

So important are these factors that The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) provides standards to follow for different kinds of buildings.

Reducing occupancy in enclosed spaces will also go a long way in reducing infection risk by the Covid-19 virus. This works because occupants receive more fresh air through the ventilation.


Final Thoughts



The return to the new normal necessitates many changes in buildings’ structure, optimizing the HVAC systems, and reducing occupants. More importantly, you need the best tools to continually monitor and track indoor air quality (IAQ) through ventilation rate and air change.


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