The adoption of electric vehicles improves the quality of the air and the climate outlook

If you've ever wondered how important adoption of electric vehicles (EVs) is for the environment, a new study shows that switching would improve overall air quality and reduce carbon emissions.

The Northwestern University study quantified the differences between air pollution generated by battery electric vehicles and internal combustion engines. The researchers found that even when their electricity is produced from combustion sources, electric vehicles have a net positive impact on air quality and climate change.

"Unlike many scary stories about the effects of climate change that we read in the news, this work addresses solutions," said Daniel Horton, lead author of the study, at Northwestern. "We know that climate change is happening, so what can we do about it?" A technologically available solution is to electrify our transportation system.

Research published Friday, April 5 in the journal Atmospheric environment. Horton is an Assistant Professor of Earth and Planetary Science at Northwestern Weinberg College of Arts and Sciences. Jordan Schnell, a postdoctoral fellow at the Ubben Program for Climate and Carbon Sciences at the Institute for Sustainability and Energy at Northwestern, was the first author of the paper.

To quantify the differences between the two types of vehicles, the researchers used an emissions remapping algorithm and simulations of air quality models. They used these methods to closely examine two pollutants related to automobiles and power emissions: ozone and particulates. Both are major components of smog and can trigger various health problems, such as asthma, emphysema and chronic bronchitis.

To fully take into account the complexity of the changes in the chemistry of atmospheric pollution, the researchers took into account several variables:

• Adoption rate of potential electric vehicles
• Electricity Generation for Electric Vehicles, Including Our Current Combustion Blend, Our Combustion Only Sources and Our Enhanced Emissions Free Renewable Energy
• Geographical Locations
• Seasons and times of the day

Ozone levels decreased in all areas during hot month simulations. In winter, however, ozone levels increase slightly but are already much lower than in the summer due to a chemical reaction that occurs differently during periods of less sunlight.

"In all scenarios, we found that more cars were switching to electric power, better summer ozone concentrations," Schnell said. "No matter how electricity is generated, the more you remove from combustion cars, the better the quality of the ozone."

Particles, also called "haze", decreased in the winter but showed greater variation depending on the location and how the energy was generated. Sites where the energy mix of their energy park is larger, for example, have experienced an increase in haze during the summer. Sites with clean energy sources have, however, experienced a drastic reduction in man-made fog.

"We found that in the Midwest, the increase in electricity demand related to EV charge in our current energy mix could result in a slight increase in particulates in the summer due to dependence on from coal-fired electricity generation, "said Schnell. "However, if we convert more of the Midwest's electricity generation to renewables, particle pollution is drastically reduced.In the Northwest Pacific or the Northeast, where there is already more clean energy available, the adoption of the EV, even with the current energy mix, will decrease particulate pollution. "