Skip to main content

Clearing the air

Concordia researchers and alumni are out to improve every breath we take
November 28, 2023
By Jordan Whitehouse

A hazy skyline of Old Montreal with muted colors, featuring the sun as a pale disc in a smoggy sky. The Saint Lawrence River is in the foreground reflecting the city's silhouette, and various buildings are visible, some under construction. There's a sense of calm despite the overcast atmosphere, with a small boat visible on the water. The Port of Montreal shrouded in a haze of smoke. Several smog warnings were issued across Quebec in 2023 due to forest fires. | Photo: Shutterstock

Twenty-two thousand.

That’s the number of breaths the Canadian Lung Association estimates we take every day.

Most of the air we intake is made up of nitrogen or oxygen, but not all of it. The rest can consist of harmful gases and particles.

Take volatile organic compounds (VOCs), which are gases that can be emitted from a wide range of common household items like carpets, paints and even computers. Some VOCs can cause minor irritations like headaches — some have also been linked to cancers.

It’s a similar story outdoors, where pollution from sources like diesel vehicles and wildfires can contribute to a hazardous cocktail of airborne chemicals. Some of these could include gases like carbon monoxide that interfere with oxygen delivery to organs, and aerosols like soot that make it hard to breathe.

Although Canada has some of the cleanest air in the world, 86 per cent of Canadians live in areas where air pollution exceeds World Health Organization guidelines.

It is estimated that air pollution in this country is annually linked to 15,300 premature deaths, 2.7 million asthma-symptom days and 35 million acute-respiratory symptom days. The cost of these health impacts is thought to be about $120 billion per year.

One piece of good news, say experts, is that air quality has garnered more attention from government, industry and other stakeholders of late. The pandemic and the associated focus on indoor air quality is one reason. The wildfires that raged across Canada this past summer is another.

This renewed focus also means that the work of air-quality researchers and alumni from Concordia — one of the top centres of study in Canada on the issue — is getting increased attention and application in the real world.

It’s still a tough battle to improve our air, they say, but progress is happening. The keys to making even further headway: more collaboration, more education and more hard work.

In the lab

Fariborz Haghighat, a researcher in the Department of Building, Civil and Environmental Engineering, has been on the air-quality front lines for decades.

In the wake of the September 11, 2001, attacks in New York City — an event that exposed the harmful effects of particulate matter and gas in the air, most noticeably at what became known as Ground Zero — Haghighat established his indoor air-quality lab at Concordia. It is now widely considered one of the top facilities of its kind in Canada.

A portrait of a professional man with dark hair and a slight smile, wearing a gray suit, patterned tie, and a lavender shirt. He is standing in an office environment, with a blurred background featuring vertical window blinds to the right. “One of the big issues is buildings themselves and the materials inside of them,” says Fariborz Haghighat.

Working closely with industry partners, Haghighat and his fellow researchers have two primary tasks: testing indoor materials to determine the source of contaminants, and developing technologies and methods to purify the air.

“One of the big issues here is the buildings themselves and the materials inside of them,” says Haghighat. “Look at your desk, the walls around you — they’re painted. Look at the carpet — it’s synthetic material. So many materials are synthetic, and if they’re brand new, they emit gases. If they’re old, they decompose and can also release gases.”

Other than VOCs, some of the more common contaminants found inside buildings include carbon monoxide brought in by air intakes, dust mites from carpets and fabrics, moulds and bacteria from damp areas and stagnant water, and ozone from photocopiers and electric motors.

Another big issue is what people bring inside with them, adds Haghighat.

Back in 2009, he co-authored a report for Public Works and Government Services Canada that included an in-depth analysis of the air quality in several office buildings.

No occupant had complained about the air inside these buildings, yet the researchers found that it was contaminated with a number of harmful gases. Their concentration levels were 10 times higher than what was found outside, says Haghighat.

The main culprit: personal-care items like deodorants and hair-care products.

Photocatalytic air purification systems — which use energy from light to clean the air — are one tool that more people are using to try to combat some of these contaminants. Haghighat and his colleagues have been looking at these too, with sobering results.

“Surprise, surprise, we find that most of them make the indoor air quality worse than before,” he says.

“For example, we’ve found that when a photocatalytic airpurification system is used to remove methanol alcohol from indoor air, it created formaldehyde, which is more poisonous than the original gas.”

In response, Haghighat and his team are currently working on developing new photocatalytic air-purification systems that don’t create hazardous byproducts.

It’s not easy work, he admits. “But we’ve done some preliminary studies that are reducing them. So, you’re always trying to remain optimistic.” 

Smart materials

One researcher from Haghighat’s lab who provided quite a bit of optimism was Zahra Shayegan, PhD 21.

Now a postdoctoral researcher at the Institut national de la recherche scientifique, Shayegan developed a novel solution to help degrade indoor air contaminants as a Concordia student. She not only won the university’s Doctoral Prize in Engineering and Computer Science for her efforts, but a Governor General’s Academic Gold Medal as well.

A woman with short hair is smiling and wearing academic regalia, which includes a maroon and white gown, typically worn for graduation ceremonies or other formal academic events. She is positioned outdoors with trees and a building with white window frames in the background. “Imagine this: smart materials that reduce energy consumption and indoor pollutants. I think it’s going to happen soon,” says Zahra Shayegan, PhD 21.

Thinking about two of the unique challenges to improving indoor air in a country like Canada helped set Shayegan on her research path.

“One is that as Canada continues to pursue its net-zero energy targets, buildings are becoming more airtight,” she notes. This reduces the ventilation that can move contaminants out of the building.

“The second challenge is that we can’t just open our windows in winter to improve ventilation and dilute the air.”

Part of Shayegan’s innovation came through the use of photocatalysts, which are used in a variety of applications, including eliminating pollutants in water. Photocatalysts work by accelerating specific chemical reactions like oxidation through the use of light.

The process doesn’t always work indoors, however. But, using the unique real-world conditions available in Haghighat’s lab, Shayegan developed photocatalysts that can remove indoor air pollutants in humid conditions and using a building’s own indoor light sources.

Materials like these still have to improve before they can be commercialized, says Shayegan. But she sees a near future where that is a definite possibility.

Right now, for instance, some windows are coated with smart materials that improve energy efficiency. “Why couldn’t that be done for improving indoor air, too?” she asks.

“Imagine this: The outside of the window is coated with a smart material to reduce energy consumption, and the inside of the window is coated with a material for the removal of indoor pollutants. I think it’s going to happen soon. We’re not far from it.”

A cityscape obscured by a haze, with the spires of two churches prominently rising in the foreground. The background shows obscured buildings and construction cranes, indicating ongoing development. Satellite dishes and rooftop equipment are visible on the buildings in the foreground, contrasting the old and the new in an urban environment with air quality issues. City of Montreal officials urged people to stay indoors where possible as city’s air quality plummeted to the worst ranking in the world by IQAir on June 25, 2023 | Photo: Shutterstock

We need collaboration

Lexuan Zhong, PhD 13, is another Concordia graduate who worked in Haghighat’s lab. Like Zahra Shayegan, Zhong was also interested in developing photocatalytic oxidation technologies, specifically ones that can remove VOCs from buildings. Her PhD thesis was also awarded a Governor General’s Academic Gold Medal.

A professional portrait of a young woman with short hair, smiling at the camera. She is wearing a dark business suit with a white collared shirt and has her arms crossed in front of her, conveying confidence. The background is a plain, neutral grey, putting the focus on her. “The pandemic showed us that we need lots of different people from lots of different countries working on solutions together,” says Lexuan Zhong, PhD 13.

She is now an associate professor of mechanical engineering at the University of Alberta, and has expanded her indoor focus to include other gaseous contaminants, as well as harmful particles and bioaerosols in the air.

Zhong does most of this work at U of A’s Built Environment Technology Lab, which she founded and still directs.

One bioaerosol that she has looked at quite extensively is SARS-CoV-2, the virus that causes COVID-19. More specifically, she and her co-researchers have studied how the virus moves through ventilation systems and how these systems might be designed or adapted to control the virus.

For the past three years, Zhong has focused on exploring ultraviolet (UV) germicidal technology, which uses light to deactivate the DNA of viruses, as well as bacteria and other pathogens.

“This technology is already implemented in places like hospitals, but it’s not so commonly used in commercial and residential buildings,” says Zhong. “Part of my research work is focused on identifying the critical design elements that could expand its use.”

One of the big benefits of using UV technology like this is that it doesn’t use chemicals to disinfect the air. And because nothing is added, the process is relatively simple, inexpensive and requires minimal maintenance.

But this doesn’t mean that the technology is easy to develop at scale or that it’s easy to expand into commercial and residential markets. It’s critical for researchers working on air quality to partner with industry and other researchers, says Zhong.

“The pandemic showed us that we need lots of different people from lots of different countries working on engineering solutions together,” she adds. “These are not easy problems to solve, and so we need collaboration. That’s the only way we can make sure people beyond academia are aware of these problems and are protected.”

Hyperlocal air pollution

Collaboration is at the heart of Gregor Kos’s research.

The Department of Chemistry and Biochemistry senior lecturer is interested in outdoor air quality, especially in urban areas.

“I’ve also always been interested in what’s happening out in the field, rather than in the lab,” says Kos. “And so that’s why now, for example, I’m working with the community of Kahnawake outside of Montreal. I’m talking to people, doing data acquisition and analysis and community science to understand their air quality and how it impacts their lives.”

A close-up portrait of a man with a friendly smile, wearing round-framed glasses. He has curly, dark hair with touches of gray and a short, neat beard. The man is dressed in a light-colored, striped button-down shirt, and the background features a rustic, weathered wooden fence that adds a textured backdrop to the image. “Despite resistance to decarbonization, I don’t think we have a choice to act on this. If we continue to act, it will be for the benefit of all of us," says Gregor Kos. | Photo: Oriane Morriet

Kos says that the two biggest concerns when it comes to outdoor air pollution right now are ozone (a key product of photochemical smog) and particulates, both of which are primarily produced by emissions from motor vehicles, solid-fuel burning and industry.

Wildfires can also be a significant source of pollutants, as they were across Canada this past summer.

Health Canada estimates the annual health impacts of wildfire smoke at $5 billion to $21 billion.

The silver lining, however, is that air pollution in Canada has been significantly declining since the 1970s.

According to the National Air Pollution Surveillance Program, lead concentrations in the air have decreased by 97 per cent, and sulphur dioxide levels by 96 per cent since 1970. Between 1970 and 2008, particulate matter decreased by more than 50 per cent.

But, as Kos notes, these macro numbers don’t tell the whole story. Certain communities and neighbourhoods can be impacted more than others.

“We’ve seen in past years that some streets might be quite badly affected by air pollution because of things like traffic and weather patterns, whereas just a few blocks away are showing much cleaner air,” he says. “This could make a big difference for someone deciding, for instance, if they want to jog on Sherbrooke Street in downtown Montreal, where there could be a lot of air pollution, versus just a few blocks away.”

These hyperlocal air pollution issues are Kos’s focus right now. To get a better understanding, he and his partners deploy several air-monitoring stations in specific areas of a community.

In the Mohawk Territory of Kahnawake, just south of Montreal, Kos has built and deployed about 20 monitoring stations with community members.

“They have been concerned about air-pollution levels for quite a while, and so our goal is to build this dense network of stations with them and then make that data available to the community so that they can decide what to do about it,” he says. 

The science ‘has to be communicated properly’

Xianming Zhang is also going small in his pursuit to understand air pollutants. But rather than looking at the particular concerns of one community, he is taking a deep dive into the molecular level of thousands of chemicals we breathe in every day.

A portrait of a man wearing a light grey, collared shirt and glasses. He is looking directly at the camera with a subtle smile. The background is an indoor setting, softly focused with rows of frosted glass windows and warm lighting, which suggests a corporate or academic environment. “There can be more than 10,000 chemicals in the air you breathe,” says Xianming Zhang.

“There can be more than 10,000 chemicals in the air you breathe,” says Zhang, an assistant professor in the Department of Chemistry and Biochemistry.

“My work is focusing on detecting and screening for this large number of chemicals in the complex mixture of our air and to determine what chemicals are of concern and what are their sources.” 

Zhang also looks at specific groups of chemical compounds, most of which are used in various commercial products.

One example is the organophosphate flame retardants that are commonly found in furniture. Typically, when regulators assess the harmful effects of chemicals like these, they don’t consider what is produced from chemical transformations in the atmosphere.

That’s a problem, says Zhang.

In a 2023 study published in One Earth, Zhang and his collaborators found that the transformation product of an organophosphorus antioxidant is more stable in the environment and causes higher risk than well-known organophosphate flame retardants.

The researcher adds an important caveat about toxicity.

“Usually, when people hear that breathing in a certain chemical can be toxic, they get really concerned,” he says. “But the toxic effect depends on the exposure — how much of the chemical can get into your body through different environmental pathways. Exposure and toxicity together tell you the final risk of the chemical, and that’s what I’m also trying to study.”

The World Health Organization and Health Canada publish details about the harmful exposure levels of various chemicals in its indoor and outdoor air-quality guidelines, Zhang observes.

As for the prospects of fewer harmful chemicals ending up in the atmosphere, he is cautiously optimistic.

“We’re only going to see improvement if all of the different stakeholders are working together,” he says. “The scientific evidence has to drive this, but it has to be communicated properly with policymakers as well as with industry actors that are producing some of these chemicals.” 

A way forward

Fariborz Haghighat says that another key to air-quality improvement is education.

“I honestly believe that in order to be able to buy a house or a building, people should be trained properly in how to use that building,” he says.

It’s not as strange as it sounds, he adds. Through Annex 35, an International Energy Agency initiative, Haghighat learned about how teachers in the city of Trondheim, Norway, were taught how to use a new school. “They were able to provide a safe and healthy indoor environment for the children and themselves while reducing the building’s energy consumption,” he says. “They were asked to change their shoes and clothes in a room before entering the school’s main building. They are trying to prevent contaminants from coming into the school from outside. We need that kind of thinking everywhere.”

Gregor Kos says we need a similar type of thinking around decarbonization if we want to see continued improvements in outdoor air.

“The source of both CO2 emissions and greenhouse gas emissions, as well as pollution, is to a large extent linked to fossil fuels and fossil-fuel combustion,” he says. “My hope is that with the decarbonization of economic activity, of energy production, we will also see a considerable drop of toxic emissions and trace gases, but also particulates, and therefore an improvement in overall air quality.”

One sign of hope could be the transition to electric vehicles (EVs). In a recent study out of the University of Southern California, researchers showed that as EV adoption increased within a given zip code, both local air-pollution levels and asthma-related emergency room visits dropped.

“Despite quite a bit of resistance to decarbonization, I don’t think we have a choice to act on this,” says Kos. “And if we continue to act, it will be for the benefit of all of us.” 

Back to top

© Concordia University