Breath of Fresh Air

— By Chris Marasco —

Improving IAQ to better protect your customers.


The COVID-19 pandemic has been a catalyst of disruption for more than a year. In 2020, the virus quickly shut down many restaurant locations while forcing retail businesses to enforce strict guidelines that instructed customers to wear masks and stand 6 feet apart. In many situations, consumers shifted toward online stores to make their purchases as opposed to gathering in person at a brick-and-mortar location.

Chris Marasco

While the pandemic turned many lives upside down, one positive outcome was that it pushed the topic of indoor air quality to the forefront of the news cycle. Improved IAQ is now regularly discussed when conversations take place regarding COVID. Now, with the rise of the Delta variant, IAQ has become a prime focus nationwide.

There continues to be a growing concern about viruses, mold and the overall degradation of indoor air inside retail and other commercial spaces. IAQ is under a microscope because we are living through a pandemic. It is the responsibility of HVAC manufacturers to develop solutions that improve IAQ and ensure building occupants have fresh, clean air to breathe.

With the busiest shopping seasons quickly approaching, it will be important for building owners to provide a safe space for customers to do their holiday shopping. With the pandemic continuing to rage onward and COVID numbers continuing to rise, this will include providing optimum IAQ levels throughout buildings.

Mechanical HVAC equipment provides the best resource for improving and enhancing air quality indoors. When defining what we consider as great IAQ, we look for air that contains no contaminants or harmful concentrations. We want to create an atmosphere where occupants are satisfied with the air quality. Should the occupants become dissatisfied with the air quality, there is a substantial IAQ issue.

There are three areas that are key focal points when improving IAQ: controlled ventilation, dehumidification and filtration.

Controlled Ventilation

According to both the World Health Organization (WHO) and the U.S. Centers for Disease Control (CDC), adequate ventilation is an important tool in limiting transmissions of pathogens. Controlled ventilation is the rate at which an HVAC unit can push fresh air indoors. The general rule is that the air outdoors is fresher than indoor air. Occupants will be able to breathe easier if there is more outdoor air in an enclosed space.

We have all heard the saying “go outside to get a breath of fresh air.” That statement holds true because the air outside is much fresher and cleaner than what accumulates indoors. Retail stores should emphasize proper ventilation to ensure adequate outside air is being delivered to the space. It will help occupants breathe easier while decreasing the number of potentially harmful particles in the air.

Many mechanical HVAC units, such as Dedicated Outdoor Air Systems (DOAS), have control systems that give building managers the ability to control the rate at which outside air is pushed indoors. In the process of pushing fresh outdoor air inside, these machines also extract indoor air, helping prevent the spread of pathogens from one space to another.


Controlling humidity levels is another key to improving IAQ. Proper humidity levels not only increase comfort but also limit pathogen growth. Mechanical HVAC equipment is developed to handle latent loads associated with outdoor air. When replacing the air inside with fresh outdoor air, controlling the humidity levels is paramount. Relative humidity levels should be between 40% and 60%.

If the humidity levels are above 60%, the air can be sticky or muggy, which would create an unpleasant feeling for customers. In addition, mold, mildew and organic growth could start to develop because of the moisture in the air, making for a potentially harmful situation for occupants.

Humidity levels below 40% also create an uncomfortable feeling for building occupants because the air is dry. To keep customers comfortable and prevent organic growth, levels should stay between the recommended ranges.


With a busy holiday season approaching, stores will likely be packed with shoppers. Filtering the air in these crowded spaces will be necessary to help prevent the spread of harmful pathogens. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is now recommending the use of MERV 13 filtration for most applications. The MERV 13 rating means the filters can remove 90% of particles between 1-10 microns in size.

Prior to the pandemic, MERV 8 or MERV 10 were typically the ASHRAE recommendations. With the increased focus on IAQ, the decision was made to increase those standards, which is a positive across the board. By increasing the standards, HVAC systems are filtering more particles from the air. For building owners, any improvements to filtration will inherently have benefits to IAQ.

Another instrument retail owners can utilize within their HVAC systems to improve IAQ is Needlepoint Bipolar Ionization. This piece of technology allows positive and negative ions to be delivered to a space via the ventilation system to attach to airborne particulates, cluster and get them filtered from the air. This is also done without producing ozone or other harmful byproducts.

In addition, Ultraviolet (UV) lights can also be utilized. ASHRAE has been recommending UV lights for many years stating “Ultraviolet germicidal energy (UV-C) has been shown to inactivate viruses, bacteria and fungi.” UV lights are also common in hospitals due to their effectiveness in killing certain bacteria.


While the focus of improving IAQ should be placed on controlled ventilation, dehumidification and filtration, regular maintenance remains a pivotal instrument as well. Proper maintenance will increase longevity, provide for proper operational performance and reduce the probability of failure. Mechanical HVAC units provide the best opportunity to increase IAQ and keep the unit working at optimal levels.

Providing Comfort

Overall, improving IAQ inside a retail space not only helps reduce the number of air pathogens in a building, it also creates a comfortable space for customers. IAQ has a direct impact on health, comfort and the overall shopping experience for consumers. With providing the best environment possible for customers being the goal, enhanced IAQ continues to be an area of emphasis. Controlling ventilation, dehumidifying the air and proper filtration will help retail owners improve their IAQ leaps and bounds above its current state. If limiting harmful pathogens inside a building is the goal, improving IAQ is the solution.




— Chris Marasco is the product manager at Modine Manufacturing Company, which specializes in thermal management systems and components, bringing highly engineered heating and cooling components, original equipment products and systems to diversified global markets.

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