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Effects of Poor Ventilation on Health in the Workplace

According to Professor Joseph Allen at Harvard’s School of Public Health, humans spend an average of 90% of their time indoors. Therefore, it is crucial that we are aware of air quality and proper ventilation. Allen, director of Harvard’s Healthy Buildings Program, says a healthy room should rotate 5-6 air changes per hour (ACH). That means air should completely recirculate through a space 5-6 times each hour. Despite those numbers, most buildings only rotate 1-3 ACH. More alarming, homes generally rotate less than one ACH! In today’s world, people are no longer in the dark about the importance of good ventilation in a building. They understand the importance of improved and healthier air quality. In this blog, we’ll explore the causes and effects of poor ventilation on people’s health. Additionally, we’ll explore how to fix the problem of inadequate ventilation.

What Causes Poor Ventilation in the Workplace?

What causes poor ventilation

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Poor ventilation is caused by a couple of key factors. In general, buildings are created with energy efficiency, business objectives, and the bottom line in mind. Many companies fail to seriously consider the ventilation systems and the overall human health ramifications that go with poor ventilation. Two of the main causes of poor ventilation are poor air circulation within a space and poor design of the mechanical ventilation system. 

Poor Air Circulation

Poor air circulation refers to a lack of air movement all together. That means the air is just sitting stagnant in a space.  This goes back to what was mentioned earlier – the air changes per hour (ACH). Remember, a healthy space rotates air at a rate of 5-6 ACH. We can combat poor air circulation with very simple actions. Simply open a window to get more outdoor air flowing through the facility. Add portable air purifiers with HEPA filters. Turn on a ceiling fan to remove stagnant air. These are some simple and very manageable steps that will make a huge difference in changing the lack of adequate ventilation. 

Poorly Designed Ventilation System

Poor ventilation system design refers to a ventilation system that is not properly or effectively pushing air. This is caused by poor placement of outdoor intakes or blocked vents due to room arrangements. Indoor air pollutants and contaminants (more on that later) often exacerbate these system shortcomings. Similarly, poor air circulation also exacerbates these pollutants and contaminants.

Effects of Poor Ventilation on a Building

Effects of poor ventilation on a building

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Sick Building Syndrome

Sick building syndrome describes when occupants inside a building experience acute discomfort and health problems directly linked to a building’s environment. This happens when poor ventilation creates a rise in carbon dioxide levels in a building, which in turn creates a significant increase in the fine aerosol particles (contaminants) present in the air. These fine aerosol particles are exhaled during talking, sneezing, coughing, and even breathing. Without proper room ventilation, these particles are, consequently, breathed in by others in the environment.  In addition, the airborne contaminants listed below also cause poor air quality.  When combined with poor ventilation, these indoor contaminants can cause many health issues and can have many adverse effects, including health risks.   

Other Airborne Contaminants Include:

  • Tobacco smoke
  • Carpet and other office furnishings
  • Bathroom air fresheners
  • Formaldehyde from laminate flooring or other pressed wood products
  • Cleaning materials
  • Paints
  • Glues
  • Copy machines
  • Dirty ventilation systems
  • Pesticides
  • Gas stoves
  • Improperly vented heater sources
  • Outdoor environmental factors – including pollens

Effects of Poor Ventilation on Health

effects of poor ventilation on health

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Poor air ventilation in offices and schools is linked to significantly impaired cognitive functioning. This includes an altered ability to think clearly and creatively. Some of the other adverse health effects due to poor ventilation include:

  • Headaches
  • Fatigue
  • Trouble concentrating
  • Respiratory Symptoms: Irritation of nose, shortness of breath, eyes, throat, and lungs
  • Trouble with analytical thinking

In addition to the aforementioned adverse health effects, indoor air pollution and Sick Building Syndrome have also been linked to more serious health problems. Some of the health problems that may occur include asthma, Legionnaires Disease, hypersensitivity, pneumonitis, humidifier fever, and even cancer due to asbestos.    

Feel free to check out the EPA facts sheet on Sick Building Syndrome here:

Four Ways to Fix Poor Ventilation

Ceiling Fan for better ventilation

Shelter Lounge, Green Lake – Seattle, WA

Indoor air quality is not a choice. It’s an essential requirement. In fact, the EPA, CDC, OSHA, NIH, and ASHRAE all indicate that employers must provide health and comfort for their employees. These organizations have set IAQ standards for eliminating contagions and viruses, pollution, managing humidity, and controlling heat. This is why it is crucial to keep air quality in mind at all times. Your employees’ health depends on it. 

In order to fix poor ventilation and take charge of keeping employees healthy, consider the HVAC unit, the building humidity levels, the use of portable air purifiers, and the essential addition of ceiling fans. In this section, let’s take a closer look at each of these considerations.

1 – Know Your HVAC Needs

To begin with, it is important to consider the correct size and cooling needs of the HVAC unit. Be sure your HVAC/air conditioner units are not too big for the space. If, in fact, it is too big, it will cause your system to run for shorter amounts of time. This is called short cycling. If short cycling occurs with heating, the fan will not run long enough. On the other hand, if short cycling occurs with cooling, it creates smaller bursts of air, which equates to minimal cooling and dehumidifying. Both heating and cooling with the wrong size HVAC unit will cause a lack of ventilation. Given these points, let’s move on to our next topic…humidity levels.

2 – Know Ideal Humidity Levels

Humidity levels are extremely important for employee health.  According to the Harvard School of Public Health, the ideal humidity level in a room is 40%-60%. The respiratory system defenses need humidity at optimal levels to function most favorably. Furthermore, if the levels vary too much above or below the ideal range, it will have adverse effects on health (as mentioned above in the Health Effects of Poor Ventilation section). 

Too High / Too Low – Humidity Levels

When humidity levels are below the ideal range of 40%-60%, it can actually cause viruses to live longer, which allows for easier transmission. Additionally, low humidity levels slow the rate that droplets evaporate, thus allowing viruses to live longer in the air. When humidity levels are above the ideal range of 40%-60%, it can cause mold. Mold is not something any building wants to mess with! According to the Mayo Clinic, mold can cause major allergic reactions and has been linked to asthma and breathing restrictions. Furthermore, if a building’s lack of natural ventilation causes toxic mold, this can be even more dangerous for one’s health.

3 – Add Portable Air Purifiers 

When a window can not be opened in a facility or a fan is not present, portable air purifiers can help with ventilation. Consider an air purifier with a HEPA filter. HEPA filters will remove up to 99.97% of particles from the air – even those fine aerosol particles.  Be mindful, however, that the room size will dictate the number and size of air purifiers needed to work effectively in your space. 

4 – Install Ceiling Fans

Ceiling fans will greatly improve your warehouse air quality.  In fact, ceiling fans will help you achieve Indoor Air Quality (IAQ) standards, which in turn improves worker health, comfort, and performance. 

With the current climate surrounding Covid-19, there is a need for employers to keep warehouse air quality clean and healthy for employees. Recently, MacroAir Technologies proudly partnered in helping to fund an Air Movement and Control Association International (AMCA International) study. 

AMCA Study Shows Ceiling Fans Help Create Healthier Warehouses 

Air Movement and Control Association International (AMCA International) released a new report on a year-long study giving Covid-19 guidance on running large diameter ceiling fans in warehouse spaces. 

AMCA International, in collaboration with Concordia University, and an elite team of scientists and engineers, just released the new report: “AMCA COVID Guidance for UNDUCTED Fans – Modeling Ceiling Fans”. The goal of this study was to understand the effect of large-diameter (larger than 7ft) ceiling fans on COVID-19 exposures in warehouses (Ivanovich, Gunzner, & Arnold, 2021). The study was based on over 200 simulations conducted in a 330ft x 150ft x 28ft warehouse. Below are the major conclusions. 

AMCA Report At A Glance 


  • Operating a large diameter ceiling fan (LDCF) at the highest speed in a downward direction is the most effective option to help reduce the concentration of airborne particles from loud speaking (shouting) in a sparsely populated warehouse setting (Wang, 2021). 
  • There was also a reduction in airborne particle concentration when a fan was running in reverse direction at the highest speed in a sparsely populated warehouse setting (not as great of a reduction as in a downward direction) (Wang, 2021).  
  • Operating a ceiling fan at a slower speed will show a slight reduction in the concentration of airborne particles from speaking loudly when occupants are close to the fan, but not as much as at the highest speed and not outside the fan region (Wang, 2021).  
  • Reducing fan speeds and running in reverse could slow all airflow, thus actually increasing the concentration (Wang, 2021).


  • No matter how far the workers are from the fans (in summer months), operate fans downward at the highest appropriate speed (while still keeping people comfortable) in either direction – forward or reverse (Wang, 2021).
  • No matter how far the workers are from the fans (in winter months), operate fans downward at the highest appropriate speed (while still keeping people comfortable), OR operate the fans in reverse at the highest appropriate speed (Wang, 2021).
  • Open windows and doors in your warehouse and operate ceiling fans wherever possible (Wang, 2021).
  • Do not locate employees directly next to each other for long periods (Wang, 2021).
  • Operate ceiling fans at the highest possible rate in either direction while still keeping your employees comfortable.   

MacroAir proudly stands behind helping to create healthy, well-ventilated environments for all people. Their HVLS fans certainly are a necessary addition to all warehouse spaces. They truly care about keeping people healthy.

MacroAir Cares – #MacroAirCares 

MacroAir Technologies was a proud partner in helping to fund AMCA’s recent study. They stand firmly behind helping to create healthy and well-ventilated environments for all. Additionally, they truly care about your employees and their well-being.

MacroAir offers large ceiling fans for your commercial and industrial facilities ranging from 6-24 feet in diameter. With the addition of fans, air will be constantly moving throughout the space. MacroAir's helpful customer care representatives are happy to help you find the exact fan perfect for your facility’s needs. 

Not only will a ceiling fan increase natural ventilation, but it will also keep workers healthier. In fact, a ceiling fan will work with an existing HVAC system to cool the space more efficiently. These things combined create a better overall work environment, thus helping companies with the bottom line.

Next Steps

Blue Motif Crack Shack Costa Mesa

Blue Motif Crack Shack Costa Mesa

With humans spending an average of 90% of their time indoors and knowing the effects poor air ventilation can have on health, you now know how crucial it is to be aware of indoor air quality. By exploring the causes and effects of poor ventilation on people’s health, along with how to fix indoor air quality issues, we can provide a healthier work environment for all people and reduce the health risks of poor ventilation. Remember, air quality is an essential requirement, not a choice.

Start Today - Do Not Wait

We can help you get started right here, right now. It is time wasted if you are not working towards solving your ventilation problem today. And poor ventilation is a MAJOR problem. Assess whether your employees are comfortable, healthy, and productive - or sluggish, sick (high rate of absenteeism), and unmotivated. And let’s be honest, we all want comfortable, healthy, and productive employees. If they are not, ventilation issues may be to blame. 

Find out more about MacroAir's HVLS fans today, and improve your ventilation problems easily. 

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Ivanovich, M., Gunzner, A., & Arnold, S. (2021). AMCA COVID-19 Guidance for Large-Diameter Ceiling Fans. AMCA International. 

Wang, L. (2021, October 26). AMCA COVID-19 Guidance for Large-Diameter Ceiling Fans. Cube: AMCA covid-19 guidance for large-diameter ceiling fans. Retrieved November 8, 2021, from