Taller buildings get a bad rap. New research from U of T Engineering’s Centre for the Sustainable Built Environment (CSBE) has found that while adding height does slightly increase embodied emissions, other building and neighbourhood design factors are far more important.
The paper, recently published in Resources, Conservation and Recycling, looked at how building height affects embodied emissions for new five- to 20-storey reinforced concrete residential buildings.
“There’s a fairly loud narrative that taller buildings are bad buildings, but from a resource use perspective and an embodied carbon perspective, mathematically something seemed off,” says Professor Shoshanna Saxe (CivMin), director of the CSBE.
“Let’s say you need a certain amount of housing. If you planned to build a 20-storey building but instead you build a 10-storey one, you’re going to need to put those 10 extra floors somewhere else. That means more roads, more utilities, more elevators. Another building quickly swamps out the small increased emissions from height.”
Avery Hoffer (CivE 2T2 + PEY, MASc 2T5), lead author on the paper, says that right now, figuring out how to build more while using fewer materials is paramount.
“We’re currently facing two crises, not just in Toronto, but more broadly as a country,” says Hoffer.
“We have the housing crisis in Canada where we need 3.5 million additional units by 2030, and we also have the climate crisis where buildings account for 11% of our total embodied greenhouse gas emissions. We’re also not on track to limit global warming to 1.5°C above pre-industrial levels.”
For their study, researchers modeled 128 concrete apartment buildings, changing various key design features such as height and slab thickness. For each building version, they calculated the materials needed and the embodied emissions for the building.
When the study was complete, researchers found several design decisions have a much stronger impact on carbon emissions than height, with concrete slab size being the worst offender.
“Just the floor slabs alone can account for up to 75% of the total embodied emissions of the structure,” says Hoffer.
“What we see in Canada is that a lot of these buildings are built with slabs in the 200–225-millimetre thickness range, which is more than what we’ve found is needed. So just by changing a small amount of your floor slab, you can save very large amounts of emissions.”
While the amount of concrete is a major driver of emissions in taller buildings, the researchers found that other common design decisions can also significantly increase a structure’s carbon footprint.
“Often for ease of design and constructability, most of the floors in a building are designed to be the same,” says Professor Evan Bentz (CivMin), a CSBE investigator and co-author on the paper.
“A 15-storey building might just have two floor designs, where the top floor ends up being much stronger than it needs to be because it’s easier to just keep building the same way up.”
Saxe says that both city bylaws and norms in the industry are contributing to more polluting, expensive and resource intensive buildings.
“In Toronto, for example, there are requirements for things like step backs that require thick concrete transfer slabs, or garbage truck turn around space, which messes with floor plates.”
“There’s also an issue of construction and design culture and what we’re willing to pay for. We pay a lot to pour concrete. We don’t pay very much for top notch design.”
There is a limit to the building heights modelled in the study. Other research that has tested buildings above 20 storeys suggests the height premium does gets more pronounced at around 50 storeys and above.
“We’re not saying we should build 120-storey buildings everywhere, but we should certainly be allowing five- to 20-storeys in a lot more places and making it much easier for those heights to be built,” says Saxe.
“We need housing and we need to build it in a sustainable way. Every time we lop a unit out of a building and put it somewhere else, that second building is more polluting than having it all in one structure.”
Researchers at the Institute of Biomedical Engineering at the University of Toronto have developed a new way to grow specialized kidney cells in the lab so that they look and behave more like they do in the body.
By placing the cells on surfaces patterned with fractal shapes that mimic natural structures in the kidney, the team encouraged the cells to develop a more mature and branched form. This advance may improve laboratory models of kidney disease, and support safer and more accurate drug testing.
The study — led by first author Mary Chuan Liu (BME PhD student), with Professor Milica Radisic (ChemE, BME) as corresponding author — was published in a recent issue of Nature Communications.
The kidney filters waste from the blood while keeping important proteins, a task that depends on podocytes, highly branched cells located within a cluster of small blood vessels in the kidneys known as the glomerulus. When podocytes lose this branching structure, kidney function declines.
Growing mature podocytes in the lab has been difficult, because cells on flat culture surfaces usually stay immature. Fractal patterns, which repeat at different scales like snowflakes or tree branches, are common in biology, but their role in cell maturation is not well understood in the kidney.
The researchers asked whether recreating fractal geometry in lab-grown environments could help podocytes develop their natural form, addressing a major gap in current kidney cell culture systems.
The team first showed that the kidney’s filtering units and podocyte cells naturally have fractal, branching patterns, and that this complexity is reduced in disease. By using tissue images as reference, they designed similar fractal shapes on lab-made surfaces, then grew podocyte cells on flat surfaces and the fractal-patterned ones. Podocytes grown on fractal topography exhibited higher expression of functional markers and enhanced cell polarity.
Their work suggests that geometry itself can be used as a design tool to guide how cells grow and mature. More realistic lab-grown podocytes could improve disease modeling, help scientists study drug toxicity and contribute to the development of better treatment strategies.
Last month, the Institute for Studies in Transdisciplinary Engineering Education and Practice (ISTEP) brought together more than 70 graduate engineering students for Semiconductor Industry Night, a panel event exploring innovation and new opportunities in this rapidly evolving sector.
Hosted by ISTEP’s OPTIONS Program, the cross-disciplinary endeavour featured U of T Engineering alumni who are leaders in the semiconductor field across industry, government and academia. The panel — including Karen Bozynski, Danny Christidis (CompE 0T1), Chris Ouslis(EngSci 8T6, MASc 8T8), and Richard Fung (ElecE 0T0, MEng 0T8) — was moderated by Professor Wai Tung Ng (ECE), who recently launched a semiconductor micro credential course alongside Professor Jane Howe (MSE).
Fung — co-founder and CEO of Toronto-based company The Six Semiconductor Inc. — shared insights from his more than 25 years of experience working with semiconductors, including how the sector has evolved over time.
“There are far more career opportunities for new graduates in the semiconductor space today compared to 25 years ago,” says Fung.
“There are at least 5-10 times more companies here in Toronto alone.”
One of the driving factors behind this shift is the evolution in AI technology.
“Semiconductors are used in anything to do with computing, and today with AI, the DRAM — essentially the memory interface — has become a bottleneck. For the first time in history, performance is tied directly to memory and companies are racing to design better semiconductor chips in order to increase performance,” says Fung.
“Because the applications of AI are so broad, semiconductor design today is focused on addressing very specific applications. Gone are the days of generic semiconductors. Our company works specifically in memory interface design and it is a very exciting time.”
Between growing technical demand and recent investments from the federal government, there is significant momentum building in Canada.
Within the past year, U of T Engineering launched a semiconductor micro-credential course and the MEng Semiconductor Fabrication & Inspection emphasis to help meet industry demand. These opportunities offer participants a hands-on approach to semiconductor fabrication and design, contributing to workforce development in the sector.
Companies such as The Six Semiconductor are also making concerted efforts to nurture Canadian talent.
“We are hiring lots of interns, giving them a taste of the industry and the exciting opportunities for a rich and interesting career in semiconductors,” says Fung.
He also shared advice on entrepreneurship and leadership.
“Engineers need to be able to speak and present on a range of subjects that are not only in their area of expertise, and a great way to acquire this knowledge is simply by talking to more people, being a bit nosy, or just paying a bit more attention,” says Fung.
“As a leader, you have to understand the individuals on your team and their communication styles. These inter-personal skills are something that require real practice to acquire,” he says.
“ISTEP brings people together across disciplines and creates space for conversations such as these to happen,” says Professor Lisa Romkey, ISTEP’s associate director of graduate studies.
“The OPTIONS Program is just one of the ways in which we create learning opportunities for students to practice and hone their communication, entrepreneurship, teamwork and leadership skills so that they can go on to thrive in their careers.”
On January 24 and 25, U of T Engineering will host its first-ever Iron Pin ceremony for undergraduate students across all years of study. Facilitated by the Engineering Society (EngSoc), the Iron Pin ceremony is an independent, student-run initiative, which complements the Iron Ring ceremony that fourth-year engineering students across Canada have participated in since the 1920s.
Writer Tyler Irving spoke with EngSoc’s Iron Pin director, Jennifer Xu (Year 3 ChemE) to find out more about this newly emerging tradition.
Can you compare and contrast the new Iron Pin ceremony with the existing Iron Ring ceremony?
The Iron Ring ceremony happens in fourth year, just before you graduate at convocation. It’s run by a national body, the Corporation of the Seven Wardens, and it’s about your commitment to ethics as you enter the workplace.
The Iron Pin ceremony is a student-led initiative, run completely by the Engineering Society, although the faculty has supported us greatly. It’s about your commitment and dedication to student ethics while you are an engineering student in school, rather than in the workplace.
The Iron Ring ceremony has always symbolized the end of a journey and the beginning of something new. We wanted the Iron Pin ceremony to be about the new responsibilities you gain as you finish high school and enter the university environment.
This is the first Iron Pin ceremony at U of T, but not the first in Canada, correct?
Yes, it’s been held before at other engineering schools in our region: for example, York University, Toronto Metropolitan University and the University of Waterloo. It’s also been done from coast to coast, from the University of British Columbia to Memorial University of Newfoundland. So far, we’ve been able to find that the longest-running Iron Pin ceremony in Ontario is at the University of Windsor, which started in 2018.
It was our previous EngSoc president, Inho Kim (EngSci 2T5) who really put things into motion here at U of T, and proposed it to Dean Yip, who has been very supportive. We’re grateful for all the work that everyone has done to get us to this point.
What is the actual ceremony going to be like?
Unlike the Iron Ring, there’s nothing secret about it: transparency and mentorship are among our key values. We will have a lot of different speakers coming in to give as many perspectives on student ethics as we can.
We will hear from the Office of the Dean. We’ll also hear from some of our U of T Camp One Iron Ring wardens, though not in their official capacity, just speaking as themselves. We’ll hear from our current EngSoc president, Ken Hilton (Year 4 CompE), and from current students sharing their own experiences.
We’ll also talk about what the pin signifies and the design that we’ve chosen and created. Students will take an oath, which will be uploaded publicly online. And then there’s a ceremonial pinning where everyone in their seats can pin each other or pin themselves.
This year it’s open to students from all years, because we want everyone to have the chance to participate. Starting next year, it will only be for first-year students. Exceptions will be made for those who haven’t yet had the chance to get pinned, such as students who were on PEY Co-op placements or others who missed this year’s ceremony.
When I think of student ethics, I think of all the concerns about how AI tools have made it so easy and tempting for students to cut corners in their assignments. Is that something this ceremony aims to address?
I do think there’s a line in the ceremony about that, but the oath itself is meant to be more inspirational. It’s not a set of commandments, like “I will not do this or that.” Instead, it’s about inspiring each other to not only be good students, but to get involved in the school community.
We want people to join clubs and teams, and to create a community of upper year students who will mentor students in first year. We want students, right from their first year, to think about what being an engineer means, the responsibilities they will take on, and the role they will play in the wider world, rather than narrowly focusing only on aspects like class work. In essence, we want to help them foster a sense of personal identity while in engineering at U of T.
Tell me about the design of the pin.
Every university has their own design. They’re all very creative and look vastly different.
Ours was the result of a competition we held last semester; Ellie Jiang (Year 2 CivE) won the competition and Milena Gega (Year 3 ChemE) completed the design. It’s built around the motif of the mythological figure Atlas holding up the sky, which again connects to that theme of responsibility.
How are you feeling about this first ceremony?
It’s definitely really exciting! I’ve seen the excitement grow from where no one really knew what this was to now, where we have around 1,700 people signed up. There’s a lot we’ve had to navigate over the past few months, but we’re trying to make sure we’re going through the right avenues so that we can run this correctly and ethically. I think it’s going to be great!
From Toronto to Tokyo to Tijiuana, a new, open-source model created by U of T Engineering researchers provides — for the first time — construction-related greenhouse gas emissions budgets for 1,000 cities around the world.
“Many countries have set emissions targets for themselves at the national level,” says Professor Shoshanna Saxe (CivMin), a lead investigator with U of T’s Centre for the Sustainable Built Environment (CSBE).
“But when it comes to making decisions about what should be built and where should we build it, that typically happens at a more local level.”
“Cities around the world are wrestling with this problem, and have been leaders in the climate fight,” says Keagan Rankin (CivMin PhD student), who is co-supervised by Saxe and is the lead author on a paper published in Nature Cities that describes the new model.
“But until now, they’ve had very little guidance to go on. It’s been like trying to run a race without knowing where the starting line or the finish line are.”
Saxe, Rankin and Rankin’s other co-supervisor Professor Daniel Posen (CivMin) wanted to provide a straightforward way to help cities navigate between the need for new housing and infrastructure and the need to keep global warming below the levels set out in the Paris Agreement.
Collaborators on the project included Professors André Cabrera Serrenho at the University of Cambridge and Christian Bachmann at the University of Waterloo.
Their first-of-its-kind approach uses an extended environmental input/output model, along with statistical regression techniques, to allocate the global carbon budget estimated from climate models to 1,000 different cities around the world.
“Thanks to the work of climate modellers, we have really good estimates for the amount of emissions that will enable us to stay below two degrees of warming at a global level,” says Rankin.
“Where it gets complicated is deciding how to divide that up between countries, cities and even specific sectors. As far as we know, our model is the first one with the ability to provide city-level emissions budgets for the construction sector: we can finally see where we’re at now, and where we need to be by 2050.”
Rankin says that while the model can be used to allocate the emissions budgets in any number of different ways, for the demonstration purposes the team chose two common strategies: equally-per-capita and grandfathered.
“With the first method, you say that each human is allowed a certain amount of emissions to meet their housing and infrastructure needs. This means that bigger cities that need to service more people get bigger budgets,” says Rankin.
“By contrast, the grandfathered method accounts for the fact that cities in the developed world are already building at a much higher level of emissions per capita than those in the developing world. It reflects the reality that it will take time to re-imagine our construction habits and learn how to build more with less.”
The team has provided a handy dashboard that enables anyone to look at the carbon budget for their city, or to compare and contrast those for several cities at once.
Using this tool, it becomes clear that no matter how emissions are allocated, all cities need to get better at low-carbon construction very quickly.
For example, under the grandfathered method, the city of Toronto has only 21 years left before it exhausts its emission budget for construction — and under the equally-per-capita method, it has only seven years.
“Our model suggests that if we in Toronto want to stay below two degrees of warning, we must reduce emissions associated with construction by between 20% and 40% every year between now and 2050,” says Rankin.
“It is possible to do that: in fact we’ve published other papers that show how various strategies, such as an increased proportion of multi-unit buildings or placing new housing in existing neighbourhoods, can significantly reduce the emissions associated with new construction.”
Whether or not cities choose to adopt some or all of these strategies, Saxe says that finally having specific targets to aim at is a critical first step.
She also says the tool’s open-source methodology can be used to set emissions budgets for other sectors — such as public transportation — at the city and/or regional scale.
“Hundreds of these cities have already signed carbon neutral pledges. If they’re serious about that, they need to have a budget and a plan to meet it,” she says.
“This model provides all of them with a plausible upper and lower bound, as well as a template they can use to create their own budgets if they want. Hopefully, that will help us get from simply having a commitment to having a real, actionable plan to achieve our goals.”
Three U of T Engineering professors have been recognized by the Engineering Institute of Canada (EIC) for their distinguished contributions to engineering. Professors Markus Bussmann (MIE) and Krishna Mahadevan (ChemE) have been elected EIC fellows for “excellence in engineering and services to the profession and to society,” while Professor Konstantinos Plataniotis (ECE) has been awarded the CPR Engineering Medal for “leadership and distinguished service to a society within the Institute at the regional/local level.”
Bussmann is chair of the Department of Mechanical & Industrial Engineering. A leader in engineering education and academic administration, he has served as Associate Chair for Graduate Studies in MIE (2009-2013) and Vice-Dean, Graduate at U of T Engineering (2013-2017). Now in his second term as chair of MIE, he has promoted a culture of teaching excellence and student engagement. An award-winning educator, he has taught courses in computer programming, engineering mathematics, fluid mechanics and computational fluid dynamics (CFD). Through his research, Bussmann has made important contributions to both algorithms and applications for various materials processes, such as coatings, pulp and paper manufacturing, and materials and chemical processing. He has also made exceptional contributions to his field through his leadership roles in engineering organizations.
Bussmann played a key role in the creation of the Canadian Graduate Engineering Consortium. He served as director of the CFD Society of Canada from 2008-2013 and hosted their annual conference in 2014. He also recently chaired the 2024 Canadian Society for Mechanical Engineering (CSME) Conference. Bussmann is a fellow of CSME and the American Society of Mechanical Engineers. He received the CSME Robert Angus Medal, the society’s highest honour, in 2019.
Mahadevan is a professor in the Department of Chemical Engineering & Applied Chemistry and the Canada Research Chair in Metabolic Systems Engineering. He was a research scientist at Genomatica Inc., San Diego from 2002–2006 and held appointments as a visiting scholar in the Department of Bioengineering at the University of California, San Diego, and the Department of Microbiology, University of Massachusetts, Amherst. Mahadevan is a pioneer in the modeling and design of metabolism for industrial and environmental biotechnology and medicine. His group has developed a new approachknown as dynamic metabolic engineering for increasing bioprocess productivity, and developed new methods for enzyme discovery and strain engineering for sustainable production of valuable biochemicals for consumer materials and industrial processes. He has published more than 185 articles on these topics.
Mahadevan has received several awards for his research, including the Society of Industrial Microbiology and Biotechnology’s Young Investigator Award in 2012, the Alexander von Humboldt Fellowship in 2014, the Syncrude Innovation Award in 2014, the Biochemical Engineering Journal Young Investigator Award in 2017, and the Canadian Society for Chemical Engineering D.G. Fisher Award in 2021.
Plataniotis is a professor in The Edward S. Rogers Department of Electrical & Computer Engineering, where he directs the Multimedia Laboratory. His research focuses on image and signal processing, machine learning, adaptive learning systems, visual data analysis, multimedia and affective computing. He is a fellow of the Institute of Electrical and Electronics Engineers (IEEE), the Engineering Institute of Canada, and the Canadian Academy of Engineering. Plataniotis has made significant contributions to IEEE, serving as chair of the IEEE Toronto Section (2004-2005), during which time he expanded membership and enhanced educational offerings.
As chair of the IEEE Educational Activities Board’s Continuing Professional Education Committee (2008), he broadened academic programs for industry practitioners. He is also recognized for his leadership in the IEEE Signal Processing Society (SPS), having served as editor-in-chief of IEEE Signal Processing Letters (2009-2011) and as general co-chair for several key conferences. He now serves as president of SPS, leading more than 23,000 volunteers. In addition to his research and leadership, Plataniotis is a dedicated educator and mentor, receiving the 2005 IEEE Outstanding Engineering Educator Award for his significant impact on engineering education in Canada.
“On behalf of the faculty, congratulations to Professors Bussmann, Mahadevan and Plataniotis on these well-deserved accolades,” says U of T Engineering Dean Christopher Yip.
“This recognition by the Engineering Institute of Canada reflects the impact of our faculty members as researchers, educators and leaders in the profession, within U of T and beyond.”