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Infectious diseases and air ventilation – Why indoor air quality matters during pandemics

Writer's picture: Mikael DenutMikael Denut

Magazines in IVAeris Oy’s office: Insinööri, Tiede, and Talotekniikka.

My office is piled high with magazines I subscribed to a bit too eagerly when I started the business. Back then, I said “Yeah, let’s get it” to everything. Now I’m desperately trying to cancel them. Some of these magazines—I don’t even know where they came from—like issues of Tiede from 2008. But these ones, I want to keep. They’ve got some seriously interesting stuff.


One article I read recently talked about how bacteria and viruses can linger in the air we breathe. And it connected directly to the Old Church Park in Helsinki, where victims of a plague epidemic from 1710 are buried. Yeah, you read that right—people who died over 300 years ago are still raising important questions. How well are we actually protected against airborne infectious diseases?


Today, this isn’t just something for lab researchers to ponder. More and more research is being done to find practical ways to combat things like COVID-19. It’s time to wake up to reality: Ventilation isn’t just about comfort or energy efficiency. It doesn’t just help us focus or stay alert. During a pandemic, it’s a matter of life and death when it comes to stopping the spread of infections.



Let’s break it down. Epidemics and pandemics, like COVID-19, have put ventilation and indoor air quality front and center in today’s world. Ventilation directly impacts how effectively viruses and bacteria dilute and disappear in indoor air. When a virus or bacteria is airborne, it’s not just floating around; it’s moving, sticking, and creating risks. Aerosols and droplets—these tiny, invisible particles that carry pathogens—can linger in the air for hours. According to the WHO, SARS-CoV-2, the virus that causes COVID-19, can stay in the air for several hours and spread meters away, especially in places with poor ventilation. So, if your ventilation sucks, your whole space becomes a breeding ground for viruses and bacteria.


Now that COVID-19 has dominated headlines and research papers for the past few years, we know a lot more about how viruses survive in the air. We know that COVID-19 can remain in the air as aerosols for hours, depending on environmental conditions like humidity and temperature. The more humid the air, the longer the virus stays active. And here’s where Finland’s winter comes into play: mechanical ventilation dries the air out, and we already have naturally dry indoor air in winter. Dry air reduces the survival chances of viruses in the air. So, while people might complain about dry air in winter, it’s actually a plus when it comes to managing risks associated with airborne infectious diseases.


Mikael Denut checks the heat recovery unit (HRU) of the ventilation system.

Sure, many people humidify their homes in winter, which might make living more comfortable—but it also helps viruses stick around longer. And at the same time, a lot of places have poor or even non-existent ventilation, making it especially challenging to control infectious diseases in indoor spaces where people spend a lot of time breathing the same air. Here’s where a simple solution comes up: improve the ventilation. Don’t just settle for the status quo—boost the air changes per hour (ACH). That’s just a fancy way of saying how many times an hour the air in a room gets replaced. The more often the air changes, the less chance there is for harmful pathogens to hang around.


Here’s the bottom line: Don’t leave your ventilation up to chance. That’s like leaving your front door wide open—you’re just giving pathogens a free pass. Get a system that’s designed and optimized to effectively combat infectious diseases. It’s an investment that pays back multiple times over—not just in money but in health and safety. Now is the time to act, not wait.



The importance of ventilation and infectious diseases


IVAeris Oy technician in a protective suit in the customer’s hallway.

When we talk about ventilation and infectious diseases, one thing is clear: this isn’t just technical jargon or theoretical debate. Epidemics like COVID-19 have taught us the hard way—ventilation isn’t just about comfort or saving energy. It’s one of the most crucial preventive measures in the fight against airborne diseases. Proper ventilation can reduce the concentration of viral aerosols in the air by up to 95%. That’s right—95%. This isn’t some insignificant number. This is the difference between how many people stay healthy and how many get sick. And if you’re thinking about future pandemics—and yes, they will come—we need to make the right moves now to install, maintain, and upgrade our ventilation systems.


Effective air ventilation is a must, not an option


An IVAeris Oy technician installs a ventilation unit.

We recommend that all public spaces and residential buildings have proper ventilation systems that are regularly maintained to prevent infections. Ventilation isn’t just about comfort; it’s the first line of defense against airborne viruses and bacteria. Take, for example, the tuberculosis bacteria (Mycobacterium tuberculosis). This pathogen is known for spreading through the air in tiny droplets and can stay airborne for hours. Think about this: an infected person might leave a room, but the airborne tuberculosis bacteria they leave behind can still infect others who enter afterward. In healthcare settings where tuberculosis patients are treated, it is absolutely critical to use effective ventilation and regularly change filters to minimize the risk of transmission.


While effective ventilation strategies are essential, ventilation alone isn’t always enough to stop infections spread through aerosols—especially when there is a high viral load in the space, as we saw with the Delta variant of COVID-19. This means additional measures like mask-wearing and social distancing in public spaces are necessary. Ventilation by itself cannot significantly reduce infections if the viral load is high and the structural design of the space doesn’t support optimal airflow.


Proper design – The key to effective air ventilation


The dynamics of airflow indoors are a complex system that can’t be ignored when the goal is to create a healthy and comfortable indoor environment. Structural design can create areas where air gets trapped, so-called “hotspots.” In these areas, the risk of infections can increase significantly because the air doesn’t circulate effectively. Studies have shown that in such spaces, the air change rate (ACH) would need to be increased by over 1000 times to eliminate these “dead zones.” But that’s practically impossible to achieve with traditional methods.


Climecon Oy’s online design tool for airflow distribution patterns.

This is where proper airflow measurement and control become crucial. It’s essential to carefully design the ventilation system so that every airflow path and its distribution within the space is meticulously planned. Choosing the right vents and diffusers is critical because their throw patterns must ensure that air circulates evenly throughout the entire space. With simulations and visualizations, we can anticipate and make sure that there are no dead zones where air stagnates and where contaminants and moisture can accumulate.


Gabor Fekete cleans the kitchen ventilation duct.

Ventilation design isn’t just a nice-to-have or an extra precaution; it’s a fundamental part of a healthy and energy-efficient indoor space. Every component needs to be optimized so that air flows freely and in a controlled manner, much like a carefully planned travel route where every stop and turn is thought through. When ventilation works as planned, it avoids the problems caused by stagnant air and ensures the air quality remains high.


The end result is a comprehensive ventilation system that not only improves indoor air quality but also optimizes energy efficiency and reduces costs over the long term. This is an investment that pays off every time you step into a room and take a breath of fresh air. It ensures that a space works like a well-designed vacation spot: a comfortable, safe, and efficient environment where people thrive and feel good.



It’s not just COVID and tuberculosis – Influenza viruses and other infections


But don’t be mistaken into thinking the problem is limited to just COVID or tuberculosis. Influenza viruses and other respiratory infections also spread through aerosols, especially in poorly ventilated spaces. Influenza viruses can stay airborne for hours and infect people in areas with weak ventilation. In other words: good ventilation can significantly reduce the risk of flu spreading, especially in schools, offices, and other public places where people spend long periods together. The problem is clear, but the solution is simple: invest in ventilation.


What do you need to do now?


Think about this. People keep saying things like “winter is coming” and “are we prepared?” These aren’t just warnings—they’re real calls to action. Are you ready for the next season? If not, now is the time to act. Why take the risk when you can do something about it now? Proper ventilation can protect you and your loved ones. This isn’t a “maybe it’s a good idea” kind of thing; it’s a critical decision for your health. If you don’t know the state of your ventilation, it’s time to call an expert.



Don’t let circumstances dictate your life. Take control, ensure the quality of your ventilation, and protect the people you care about. This is an investment that pays off in health and safety. The time to act is now.


Ventilation and infection control go hand in hand


When we talk about ventilation and infection prevention, we need to understand this: ventilation and infection control go hand in hand. This isn’t just a marketing tagline or a hypothesis—this is reality. If you’re not prepared, you’re at risk. The whole game is simple: Ventilation is your front line when it comes to fighting airborne infections.


Take tuberculosis, for example—a disease that hasn’t gone anywhere. In fact, it’s making a comeback. The tuberculosis bacteria, Mycobacterium tuberculosis, is a real survivor. It can lie dormant in a human body for decades and reactivate when immunity weakens. It doesn’t float in the air for months or years, like some myths suggest—but it can persist in environments with prolonged exposure and poor ventilation.


An IVAeris Oy technician measures and adjusts the airflow.

And this is where the critical role of ventilation comes into play. Viral particles, like SARS-CoV-2, are more sensitive to environmental conditions. They can stay airborne for hours, and in aerosol form, even longer, but their activity decreases over time. Still, in spaces where people spend a lot of time together and ventilation is inadequate, even short-term exposure can lead to significant transmission chains. So think again about how you’re protecting your space and the people inside it.


Ventilation: Not just cleaning and filters, but design and strategy


Here’s the moment of truth: clean ducts alone aren’t enough. While there’s a lot of fearmongering about dirty air ducts, they don’t have a direct impact on the spread of infectious diseases if ventilation is adequate and the ducts are sealed. Dust stays in the ducts. Routine duct cleaning is often unnecessary. Focus instead on ensuring your system is designed and installed correctly, that it operates optimally, and that filters are replaced regularly. This is far more important than some random duct cleaning.



How Do You Make Sure Your Ventilation Protects You and Others Best? It starts with design and continues with quality execution. Here are a few tips everyone who cares about indoor air quality should know:


  1. Increase air change rate (ACH): By increasing the air change rate in indoor spaces, you reduce the number of airborne pathogens and make the space safer. Yeah, easier said than done. Often, ventilation systems are just barely adequate, without extra capacity to boost the air change rate. But that doesn’t mean it’s impossible—it means making the right choices with equipment and installation.

  2. Use high-quality filters and replace them regularly: F7 filters or better remove small particles, including aerosols that contain viruses and bacteria. Cutting corners with filters is dangerous if you want healthy and good indoor air quality. It’s a small investment that can save your health in the long run.

  3. Choose the right air outlets: When it comes to ventilation, it’s not just about “moving air.” It’s about how the air moves. It’s crucial to choose the right vents and outlets and ensure, through simulation and visualization, that the air circulates throughout the entire space, without dead zones where the air gets trapped. This is a critical part of effective airflow management.

  4. Mechanical ventilation: Mechanical ventilation forces air to exchange in spaces, improves air quality, and reduces the risk of infection spread. This isn’t optional—it’s a mandatory part of infection control.

  5. Air purifiers with UV light and ionization systems: These systems can kill microorganisms and significantly improve indoor air quality. Buying a high-quality air purifier during infection seasons isn’t just a good idea; it’s a smart investment that protects you and your loved ones.


Mikael Denut with a LifaAir air purifier.

What’s next?


At IVAeris Oy, we are committed to providing the best possible service for improving and optimizing ventilation. Our approach isn’t just to install equipment and hope for the best. We analyze, design, optimize, and do whatever it takes to ensure your ventilation system is ready for any health challenges the future might bring.


IVAeris Oy is here to help you. We offer customized solutions and expert support to make sure your indoor air is healthy and safe. Don’t leave anything to chance. Contact us today and make sure your ventilation is prepared to face any upcoming challenges. This isn’t a “maybe it’s a good idea”; it’s a must for health and well-being.


 

WE KNOW, WE CARE & WE GET IT DONE


IVAeris Oy

010 206 3000

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