Sick Building Syndrome – How To Protect Your Occupants

Have you ever been to a building and suddenly started feeling your eyes, nose, and throat irritated, or your skin itching? Or maybe you got a headache, felt lethargic, or had mysterious mental fatigue that you couldn’t quite explain.  You could have been a victim of what we call the Sick Building Syndrome, or SBS.

Sick Building Syndrome is a condition attributed to poor indoor air quality, and it can look a lot like a normal cold. The main difference is that all the symptoms disappear as soon as you leave the building…and it can actually be more serious than just a cold. Why? SBS can affect a person’s skin, respiratory, and neurological systems. For those who are more susceptible, it can even lead to dangerous asthma attacks.

If you are a building owner or manage a facility and often see people with terrible allergies sneezing, wheezing, with a sore throat, cough, itchy eyes, and congestion in your building, there’s more to it than meets the eye.


Because providing good indoor air quality and a safe environment to the occupants of your building is your responsibility.

More than 50 million Americans suffer from allergies, and most people don’t even realize that air pollution is worse indoors than outdoors.

All allergies begin with exposure to a trigger that the body sees as an invader. In buildings, the most common allergy triggers are dust, mold, mite, pollen, pet dander, and cockroach feces. Some of these allergens are air inborne particles, and your system may be contributing to increasing their level in your building.

Most buildings have air filter systems specially designed to prevent indoor air pollution. However, if your system is under a lot of stress, undesired particles can enter your building and harm people’s comfort and health.

So how can you protect people’s health and prevent them from having allergic reactions such as Sick Building Syndrome?

Here are some important steps.

1) Check Your Air Filters

Air filters for HVAC are rated based on the Minimum Efficiency Reporting Value (MERV) scale that ranges from 1 to 16. The higher the number, the more efficient is the filter. Some filters, classified as High Efficient Particulate Air (HEPA), can block more than 99% of particles and contaminants.

In fact, there are applications in which HEPA filters are required, such as hospitals. Other applications could benefit from it, but they are not necessary. Not all buildings are prepared for HEPA filters, and that is fine.

What truly matters here is that your air filters work in such a way that prevents allergens from circulating through your ductwork and blown into the space.

dusty air duct contributing to sick building syndrome

2) Clean Your Ventilation System

Cleaning an air duct system that is not showing a clear problem may sound like blowing money, but you shouldn’t completely disregard it. Every 3 years, make sure to check what’s going on in there.

That’s because, among many other reasons, when a certain amount of dirt accumulates in your system, the dust snaps off the ducts and enters the building, decreasing the air quality for the occupants. On top of that, if you have any water leaking inside your ducts because of high humidity in your facility, you have the perfect environment for mold to grow. Mold releases spores that will circulate in your building, contributing to asthma attacks and respiratory infections.

And I know it’s not pleasant to read this, but it is easy and common for mice and other pests to get into duct systems. And hair, dead insects, and droppings when blown into the facility can cause a lot of harm.

dirt inside air duct contributes to sick building syndrome

3) Keep Humidity Under Control

We’ve already talked about mold, but don’t forget mildew, dust mites, and bacteria. They all love moisture and can multiply fast. The more they eat, the more breeding and waste you have, and that’s the real allergen.

Keep moisture low, below 50%, to keep dust mites and bacteria count under control.

low humidity protects from sick building syndrome

4) Kill What’s Already In Your Building

An effective way to kill the allergens in your building and improving indoor air quality is by using UV germicidal light.

Health studies have shown that mildew, mold, fungi, viruses, and bacteria are killed by UV light. It can be incorporated into your building in 2 ways: upper-room air or in-duct UV irradiation.

UV light also helps reduce odors, prevents clogging in pipes where algae have grown, and protects the coil, improving cooling efficiency and reducing energy consumption.

UV light in air duct treatment prevents sick building syndrome

Struggling with where to start on building maintenance? Download our ultimate maintenance guide now.

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About Midwest Machinery Company

Midwest Machinery Company is a sales representative for commercial and industrial HVAC equipment created in 1923. We offer a complete product portfolio that includes cooling towers, chillers, air handlers, pumps, and other essential pieces of equipment for mechanical systems.