Posts Tagged: air pollution

CivMin study: Electric vehicles can fight climate change, but they’re not a silver bullet

Sales of passenger electric vehicles are growing fast, but a new analysis from U of T Engineering researchers shows that on its own, electrifying the U.S. fleet will not be enough to meet our climate change mitigation targets. (Photo: microgen, via Envato)

Today there are more than 7 million electric vehicles (EVs) in operation around the world, compared with only about 20,000 a decade ago. It’s a massive change — but according to a group of U of T Engineering researchers, it won’t be nearly enough to address the global climate crisis. 

“A lot of people think that a large-scale shift to EVs will mostly solve our climate problems in the passenger vehicle sector” says Alexandre Milovanoff, lead author of a new paper published today in Nature Climate Change. 

“I think a better way to look at it is this: EVs are necessary, but on their own, they are not sufficient.” 

Around the world, many governments are already going all-in on EVs. In Norway, for example, where EVs already account for half of new vehicle sales, the government has said it plans to eliminate sales of new internal combustion vehicles altogether by 2025. The Netherlands aims to follow suit by 2030, with France and Canada to follow by 2040. Just last week, California announced plans to ban sales of new internal combustion vehicles by 2035.

Milovanoff and his supervisors, Professors Daniel Posen and Heather MacLean (both CivMin) are experts in life cycle assessment — modelling the impacts of technological changes across a range of environmental factors. 

They decided to run a detailed analysis of what a large-scale shift to EVs would mean in terms of emissions and related impacts. As a test market, they chose the United States, which is second only to China in terms of passenger vehicle sales. 

“We picked the U.S. because they have large, heavy vehicles, as well as high vehicle ownership per capita and high rate of travel per capita,” says Milovanoff. “There is also lots of high-quality data available, so we felt it would give us the clearest answers.” 

The team built computer models to estimate how many electric vehicles would be needed to keep the increase in global average temperatures to less than 2 C above pre-industrial levels by the year 2100, a target often cited by climate researchers. 

“We came up with a novel method to convert this target into a carbon budget for U.S. passenger vehicles, and then determined how many EVs would be needed to stay within that budget,” says Posen. “It turns out to be a lot.” 

Based on the scenarios modelled by the team, the U.S. would need to have about 350 million EVs on the road by 2050 in order to meet the target emissions reductions. That works out to about 90% of the total vehicles estimated to be in operation at that time. 

“To put that in perspective, right now the total proportion of EVs on the road in the U.S. is about 0.3%,” says Milovanoff. 

“It’s true that sales are growing fast, but even the most optimistic projections suggest that by 2050, the U.S. fleet will only be at about 50% EVs.” 

The team says that in addition to the barriers of consumer preferences for EV deployment, there are technological barriers such as the strain that these vehicles would place on the country’s electricity infrastructure. 

According to the paper, a fleet of 350 million EVs would increase annual electricity demand by 1,730 TWh, or about 41% of current levels. This would require massive investment in infrastructure and new power plants, some of which would almost certainly run on fossil fuels. 

The shift could also impact what’s known as the demand curve — the way that demand for electricity rises and falls at different times of day — which would make managing the national electrical grid more complex. Finally, there are technical challenges to do with the supply of critical materials, such as lithium, cobalt and manganese for batteries. 

The team concludes that getting to 90% EV ownership by 2050 is an unrealistic scenario. Instead, what they recommend is a mix of policies, including many designed to shift people out of personal passenger vehicles in favour of other modes of transportation. 

These could include massive investment in public transit — subways, commuter trains, buses — as well as the redesign of cities to allow for more trips to be taken via active modes, such as bicycles or on foot. They could also include strategies such as telecommuting, a shift already spotlighted by the COVID-19 pandemic. 

“EVs really do reduce emissions, but they don’t get us out of having to do the things we already know we need to do,” says MacLean. “We need to rethink our behaviours, the design of our cities, and even aspects of our culture. Everybody has to take responsibility for this.” 

By Tyler Irving


This story originally published in Engineering News

Modelling the health benefits of electric cars

Professor Marianne Hatzopoulou (CivMin) and her team have modelled the potential human health impacts of a large-scale shift to electric vehicles across the GTHA. (Photo: Roberta Baker)

Electric vehicles are often touted as a means of mitigating climate change, but a new modelling study suggests that their public health benefits may be just as significant.

“Local air pollution within urban environments is highly detrimental to human health,” says Professor Marianne Hatzopoulou (CivMin), who led the research. “When you have an electric vehicle with no tailpipe emissions, you’re removing a wide range of contaminants — from nitrogen oxides to fine particulate matter— from the near-road environment and shifting them to power plants. The net effect remains a large improvement in air quality.”

Health Canada estimates that 14,600 premature deaths per year can be attributed to air pollution, with more than 3,000 of these in the Greater Toronto Hamilton Area (GTHA). Hatzopoulou and her team set out to model how that might change under a significant shift from internal combustion vehicles to electric ones.

The researchers created computer simulations for a number of different scenarios, such as replacing 20%, 50% or 100% of all cars and SUVs in the GTHA to electric ones. They also modelled the effect of switching transit buses over to electric buses, and of replacing all transport trucks with newer, less emitting models.

The simulations accounted for the fact that even though electric vehicles don’t produce any emissions themselves, they increase demand on electricity plants. If those plants burn fossil fuels, they might show increased local emissions, which the team included in their model.

“We can simulate the air quality down to areas as small as one square kilometre, so even if the overall effect is positive, we can see if there are local winners and losers,” says Hatzopoulou. “We also accounted for air pollution drifting over from upstate New York and the American Midwest, which we often can detect here in Toronto.”

For each scenario, the team calculated the predicted reduction in emissions for various air pollutants. Using epidemiological data on pollutant exposures, they then estimated the reduction in premature deaths that would be observed in that scenario.

Finally, using an economic measure known as the Value of Statistical Life (VSL), they converted the reductionin deaths into a dollar figure, as a way of quantifying the social benefits of the change.

Among the model’s predictions were:

  • Converting all cars and SUVs in the GTHA into electric vehicles would cause 313 fewer deaths per year, an estimated social benefit of $2.4 billion
  • Converting all transport trucks to more efficient models would cause 275 fewer deaths, an estimated social benefit of $2.1 billion
  • Converting  all transit systems to electric buses would cause 143 fewer deaths, an estimated social benefit of $1.1 billion

I was surprised just how strong the effect was,” says Hatzopoulou. “If you bring it down to an individual level, each electric vehicle replacing a gas-powered one brings nearly $10,000 in social benefits. Those benefits are shared by everyone, not just the people buying the cars.”

The study was published today in a report co-authored with Environmental Defence and the Ontario Public Health Association. The analysis relating to transport trucks, which included contributions from U of T Engineering professors Matthew Roorda and Daniel Posen (both CivMin) and their teams, was published last month in the journal Environmental Research.

NextHatzopoulou and her team plan to use their model to study the effects of other changes, such as reducing the overall number of cars on the road by encouraging public transit or active transportation.

“Electric vehicles are great, but with even millions of them on the road, we would still have issues such as traffic congestion,” she says. “If we want to address the climate crisis, we’re going to need behavioural modifications as well.”

“One of the things we’ve learned during this COVID-19 pandemic is that it might not be critical for everyone to commute to work every dayWe would liketo quantify the benefits — both for the environment and for our own health — of making those kinds of changes.”

By Tyler Iriving

This story originally published by Engineering News

Crunching the numbers on Toronto’s King Street transit pilot

A streetcar stops on King Street in Toronto. A section of the busy east-west street travelling through downtown Toronto has restricted car traffic, and U of T Engineering researchers are collaborating with the City of Toronto and the Toronto Transit Commission to study the pilot project’s effects. (Credit: Billy Cabic via Flickr under creative commons license)

A streetcar stops on King Street in Toronto. A section of the busy east-west street travelling through downtown Toronto has restricted car traffic, and U of T Engineering researchers are collaborating with the City of Toronto and the Toronto Transit Commission to study the pilot project’s effects. (Credit: Billy Cabic via Flickr under creative commons license)

Toronto’s King Street transit pilot project aims to improve transit reliability, speed and capacity, along with a number of other measures included in a comprehensive evaluation and monitoring program. For a team of researchers, it also presents an ideal opportunity to study the effects — both direct and indirect — of traffic changes on air and noise pollution, public health and commuter decision-making.

The pilot project, launched in November 2017 and running for one year, involves altering traffic patterns on the stretch of King Street from Bathurst in the west to Jarvis Street in the east to prioritize through-traffic from streetcars, cyclists and pedestrians. Cars must take their first available right turn off the street, with through movements prohibited at eight of the 12 signalized intersections. The 504 King streetcar route is the busiest surface transit route in the city.

“There isn’t another city that’s done exactly what we’ve done, though other cities have taken measures to prioritize transit or restrict private vehicle traffic,” says David Kuperman, manager of surface transit projects for the City of Toronto. “It’s early days, but we are hearing some interest from other cities in what we’re doing because we have such a comprehensive data monitoring and evaluation program planned.”

The multidisciplinary team led by researchers in U of T Engineering is collaborating with both the City of Toronto and the Toronto Transit Commission (TTC) to gather data and share their findings and analysis. The team began taking measurements along King Street and surrounding area as early as summer 2017 to set a baseline before the launch of the pilot.

“It’s a very interesting natural experiment,” says Professor Marianne Hatzopoulou(CivE). “There are very few opportunities to conduct transportation and environmental research in a live natural laboratory like this.”

Hatzopoulou’s research investigates relationships between air quality and transportation patterns. For this project, she is using a technique called “scripted exposure studies” to measure and compare the air pollution exposure of people travelling along King Street and nearby areas, both before and after implementation of the pilot project.

“The idea is to replicate what an individual passing along or close to King Street would be exposed to, including all sorts of modes: cycling, walking, riding the streetcar, sitting in a coffee shop,” she says. “We designed four different routes involving both indoors and outdoors, along King and parallel streets, as well as cross streets.”

Her team will be carrying portable exposure monitors that measure traffic-related air pollution such as small inhalable particles and soot. They’ll also be carrying GPS units and will merge location data with exposure measurements, resulting in a detailed pollution exposure map for King Street and surrounding areas.

Dr. Cheol-Heon Jeong and Peter Murphy (both ChemE) of the Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR) at U of T Engineering have also installed several of its stationary AirSENCETM monitors throughout the pilot project area, as well as air quality monitors on two TTC streetcars dedicated exclusively to King Street routes for the duration of the project. These devices measure ozone, carbon monoxide, carbon dioxide, ultrafine particles, black carbon and PM 2.5, a standard for quantifying airborne particulate matter.

The group also includes Tor Oiamo, a professor in Geography & Environmental Studies at Ryerson University who is studying changes to noise levels, and Jeffrey Brook, a senior research scientist with Environment and Climate Change Canada and assistant professor in U of T’s Dalla Lana School of Public Health.

“This project is very exciting from a public health perspective, because we have the opportunity to collect a wealth of data on how an alteration to urban design affects health and behaviour,” says Brook. “The knock-on effects due to changes in people’s behavior could be significant, affecting not only transport and the physical environment, but people’s levels of exercise, stress, wellness and happiness, all of which have potential health benefits.”

In December the researchers met with representatives from the City of Toronto’s Transportation Services and Public Health teams to discuss coordinated data collection, information sharing, survey design and next steps.

“When a city makes a change like this, the primary goal is to improve travel times,” says Hatzopoulou. “But there are so many co-benefits that can come with that, and if we’re able to highlight those improvements to air quality and noise reduction, we’re telling decision-makers that there’s more value to unlock with these projects beyond just traffic circulation, and that’s very important.”

This story was originally published on U of T Engineering News.

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