New research reveals how widespread adoption of electric vehicles can improve air quality and human health

A new study from the Department of Civil and Mineral Engineering at the University of Toronto suggests that widespread adoption of electric vehicles (EVs) could lead to significant population health benefits.

The research team used computer simulations to show that aggressive electrification of the U.S. automobile fleet, combined with an ambitious deployment of renewable electricity generation, could result in health benefits worth between 84 and 188 billion dollars by 2050.

Even scenarios involving less aggressive grid decarbonization mostly predicted health benefits in the tens of billions of dollars.

“When researchers look at the impacts of electric vehicles, they typically focus on climate change in the form of reduced CO emissions.₂ emissions”, says Professor Marianne Hatzopoulou, one of the co-authors of the study, published in the Proceedings of the National Academy of Sciences.

“But CO₂ is not the only thing that comes out of the exhaust of an internal combustion vehicle. They produce numerous air pollutants that have a significant and quantifiable impact on public health. Additionally, data demonstrates that these impacts are disproportionately felt by low-income, racialized, or marginalized populations. »

Other team members include lead author and postdoctoral researcher Jean Schmitt, professors Daniel Posen and Heather Maclean, and Amir FN Abdul-Manan of Saudi Aramco’s Strategic Transportation Analysis team.

Members of this team had already used their expertise in life cycle assessment to create computer models simulating the impact of large-scale adoption of electric vehicles on the U.S. market.

Among other things, they showed that while the adoption of electric vehicles will have a positive impact on climate change, it alone will not be enough to achieve the goals of the Paris Agreement. They recommended that electric vehicle adoption be combined with other strategies, such as investments in public transit, active transportation and higher housing density.

In their latest study, the team wanted to take into account the non-climate benefits of electric vehicle adoption. They adapted their models to simulate the production of air pollutants common in fossil fuel combustion, such as nitrogen oxides, sulfur oxides and small particles called PM._2.5.

“The modeling of these pollutants is very different from the modeling of CO₂“, which lasts for decades and eventually mixes throughout the atmosphere,” says Posen. “In contrast, these pollutants and their associated health impacts are more localized. What matters is not just how much we emit, but also where we emit them.”

Even though electric vehicles produce no tailpipe emissions, they can still be responsible for air pollution if the power plants that power them run on fossil fuels like natural gas or coal. This also has the effect of shifting air pollution from busy highways to communities that live near these power plants.

A further complication is that neither air pollution from the electricity grid nor that from internal combustion vehicles is expected to remain constant over time.

“Today’s gasoline cars produce much less pollution than those built 20 years ago, many of which are still on the road,” Schmitt says.

“So if we want to fairly compare electric vehicles to internal combustion vehicles, we need to take into account that air pollution will continue to decline as these older vehicles are replaced. We may also see that the grid electricity becomes more environmentally friendly over time, as more and more renewable generation is installed.”

In the model, the team chose two main scenarios to simulate through 2050. In the first, they assumed that no more electric vehicles would be built, but that older internal combustion vehicles would continue to be replaced by newer, more efficient vehicles.

In the second, they assume that by 2035, all new vehicles sold will be electric. Researchers called this “aggressive,” but it is consistent with many countries’ stated intentions. For example, Norway plans to eliminate sales of non-electric vehicles next year, and Canada plans to do the same by 2035.

For each of these scenarios, they also looked at different rates of transition of the electricity grid to renewable and low-emission energy sources, that is, whether it remains roughly the same as the current rate, slows down or accelerates over the next two years. decades.

Under each of these conditions, the team simulated air pollution levels across the United States. They then used established calculations commonly used by epidemiologists, actuaries and government policy analysts to correlate these pollution levels with statistical estimates of the number of years of life lost, as well as with estimates of economic value .

“Our simulation shows that the cumulative public health benefits of widespread adoption of electric vehicles by 2050 could be in the hundreds of billions of dollars,” says Posen.

“This is important, but we also discovered that we will only get these benefits if the grid continues to become greener. We are already moving away from fossil fuel-based electricity generation, and this will likely continue in the future But for the sake of argument, we modeled what would happen if we artificially froze the grid in its current state. In this case, we would be better off just replacing our old internal combustion vehicles. by new ones – but again, that’s not a very realistic scenario.”

This finding raises another question: is it more important to decarbonize the transportation sector through the adoption of electric vehicles, or to decarbonize the power generation sector first, which is the ultimate source of associated pollution to electric vehicles?

“To that, I would say it’s important to remember that vehicles sold today will continue to be used for decades,” says Hatzopoulou. “If we buy more internal combustion vehicles now, no matter how efficient they are, we will lock ourselves into these tailpipe emissions for years to come, and they will spread this pollution everywhere there are roads.

“We still need to decarbonize the electricity generation system – and we are doing it – but we shouldn’t wait until this process is complete to put more electric vehicles on the road. We need to start on the path today of a healthier future.”