Air Quality in Buildings

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A Breath of Fresh Air: How to Improve Indoor Air Quality

The Indoor Generation Report, a survey of Canadians conducted by The VELUX Group, revealed that though most of us don’t believe we spend too much time inside, most Canadians spend upwards of 90% of their time indoors. Between work, school, shopping and relaxing at home, the vast majority of our time is spent breathing stale, indoor air. Worse still, one in six Canadians lives in an unhealthy building.  

As pandemic restrictions begin to lift and people across Canada head back to the office, return to school and venture back into indoor public spaces such as movie theaters, museums and retail establishments, indoor air quality is top of mind for all of us. But air quality isn’t a simple, single-variable concept. It’s a dynamic combination of many different factors. Fortunately, many of them are within your control.  

The Impetus 

Up until the 1970s, there weren’t strong and consistent regulations on building energy efficiency. This changed after a series of energy crises in the 70s and 80s which led to regulations which increased the thermal efficiency and air-infiltration of the building envelope. Thermal efficiency, as measured by r-value, is the insulation rating of a system, whether it is the wall, floor, ceiling, roof, etc. Air-infiltration, as measured by air leakage, is outside air that enters a building uncontrollably through cracks and openings. 

Ever since, both the national and local codes have steadily increased the thermal efficiency and air-infiltration of the building envelope – especially in Canada’s northern climate zones. Beyond regulations, building tightness has been incentivized by the R-2000 Program and the EnerGuide Rating System from Natural Resources Canada. This has resulted in structures that are more and more airtight. 

Competing Objectives 

Thanks to these efforts, buildings have been able to maintain comfortable indoor temperatures better and more efficiently than ever. However, air tightness also means virtually no fresh air is allowed in, which can be detrimental to indoor air quality. Siet ‘Foeng’ Tjong, Robertson Head of Research and Development explains, “We generally do not like to have any leaks, whether it’s water, vapor or air leaks into the building. But in some cases that does create a problem with indoor air quality.” 

We don’t often think of indoor air as necessarily being unhealthy, but it has the potential to harbor all kinds of harmful materials. As Joseph Dachowicz, Robertson’s Vice President of Marketing for Commercial Business, points out, “Buildings are filled with all kinds of man-made materials you’re just basically breathing in all day.” 

Tjong agrees, “When you have a building that is super tight, it also creates a lot more challenges for the HVAC engineer to provide balanced indoor air quality,” she said, ”and it creates a lot more load and requirements on the HVAC system to evacuate the air inside building and replace it with fresh air.” 


According to the Canadian Centre for Occupational Health and Safety (CCOHS), of the pollutants that can end up stuck inside airtight buildings, some are generated indoors, while others find their way in through cracks, open doors or windows, or even on the people going in and out. Some can come from both sources. But they all can become health and safety concerns. 

Man-Made Volatile Organic Compounds (VOCs) 

Chemicals used in the manufacture of office equipment, furniture, wall and floor coverings and construction materials can off-gas into your interior environments. Cleaning products, pest control, copying and printing can also leave variety of harmful compounds in the air. According to Health Canada, some of these VOCs, like benzene and formaldehyde, have been linked to cancer. 

With extra cleaning measures in place due to COVID-19 concerns, and more sanitizing products being sprayed on more surfaces more often, ventilation to move that particulate matter out is even more crucial.  

Biological Agents 

Bacteria, viruses, fungi and moulds can all travel through the air, causing illness, infection and fungal or mould growth. 

Combustion Pollutants 

Whether from idling vehicles, machinery, tobacco smoke, heating or cooking, combustion-related compounds such as carbon monoxide are among the most dangerous interior pollutants. High levels of carbon monoxide from a vehicle left idling in a garage can be lethal in a matter of minutes. Worse still, it’s odorless, tasteless and colorless – virtually imperceptible without a carbon monoxide detector. 

Fine particulate matter 

This is the “dust” you can see floating in a ray of sunlight and can be made up of any of the above as well as other fine particulate matter. 

Pollutants can be generated by the most innocuous seeming sources, such as housekeeping cleaners, air fresheners or printers, but are caused more precipitously by renovation, remodeling or applying new paint or finishes.  

Health & Safety Effects 

Poor indoor air quality can result in serious health effects. These can range from mild and irritating to life-threatening. Eye, nose and throat irritation are common, as well as headaches, dizziness and fatigue. At the more severe end of the spectrum, poor air quality can trigger asthma attacks, and more hazardous pollutants like radon or carbon monoxide can cause cancer or be lethal. 

Sick Building Syndrome 

When poor ventilation and indoor pollutants combine, they can lead to what’s known as “sick building syndrome.” Many occupants experience similar symptoms after entering in “sick” buildings, and their symptoms tend to resolve after leaving. Air quality this poor has been blamed for everything from sub-par student performance to reduced productivity in occupational settings. 

Air Quality Perception is Reality 

Individual perception of poor air quality is important as well. Though these considerations are more subjective, they can still affect how employees, visitors and customers feel inside your building. Odors and temperature are two of the strongest variables affecting perceived air quality, as well as air movement. Too little feels stuffy, but too much can feel drafty and uncomfortable.  

The Basics of Air Exchange  

Air exchange is a function of air infiltration, natural ventilation and mechanical ventilation. These each play a part in how much air needs to be exchanged or moved per minute, which is expressed in cubic feet per minute, or CFM. The more overall air exchanges per hour – including a measure of exchange with outside air – the better. However, the following factors and considerations contribute to what is required to manage and improve a building’s air quality and ventilation: 


The size of a building determines how much air is inside it, and therefore is an important part of the necessary CFM calculation.


Buildings with fewer or no people, such as barns or warehouses, require much less ventilation – fewer CFM – than buildings with higher occupancy, such as a school, office building or church.

Number and Type of Openings 

These can be intentional openings such as doors, windows and loading docks, as well as a building’s unintended openings which compromise its overall tightness, such as cracks and broken seals. External pollutants infiltrate a building through such openings, then the building’s tightness keeps them in.

Type of Airflow  

Unoccupied buildings may only have natural ventilation, while livestock buildings or storage buildings might use industrial fans, and buildings designed for people are equipped with complete HVAC systems. 

External temperature changes  

Outdoor temperature changes – both day/night cycle and seasonal changes – dictate what level of insulation is ideal. 

Insulation Type and Quality 

As discussed, insulation is good for energy efficiency but makes integration of fresh air a challenge. 

Make Air Quality Part of the Plan 

The absolute best way to ensure healthy air quality is to plan ahead and integrate adequate ventilation in your project from the very start. As Tjong points out, “Indoor air quality is the responsibility of HVAC engineers,” and they will be best enabled to provide that quality when their needs and input are included throughout the design process. Simply include HVAC engineers when you work with your Robertson representative. This way, fenestrations and other necessary roof and penetrations are planned for, as well as structural support for HVAC systems.  

Under Your Control 

We understand that while not everyone is undergoing a new construction design project, everyone can benefit from better air quality. Simply being aware of everything discussed so far will help you rectify any existing problems – and prevent future ones – while following these simple tips will help even more: 

  • Get healthy, fresh air into the building when possible. 
  • Establish an effective smoking policy that protects nonsmokers from secondhand smoke. 
  • Ensure your HVAC system’s HEPA filtration is changed as directed. 
  • Be careful not to place furniture or other obstacles in front of air vents, grilles or intakes. 
  • Water and maintain office plants properly to avoid extra moisture – and therefore the development of mould. 
  • Dispose of garbage promptly and properly. 
  • Pre- and post-occupancy flushing, with exterior air is recommended if your system is capable of it. 
  • Be mindful of the unintended consequences of excessive cleaning product usage. 

Also, be wary of unsubstantiated claims of many air “purifiers” on the market that claim to kill COVID-19 or purify the air through unproven means. At best, these will be an expense that accomplishes nothing. At worst, they can exacerbate indoor pollutants. For instance, ionizers generate ozone. This is unhealthy on its own, but it’s also highly reactive and can combine with other airborne substances to create harmful VOCs like formaldehyde and acrolein. 

There are steps everyone can take to improve air quality and incrementally improve the health of both buildings and the people who live, work, shop and play inside them. To learn more about how Robertson can assist in designing a custom metal building with the latest in air quality features, reach out to your Robertson representative today.