Study: Reduced emissions from electric cars could prevent thousands of deaths

When compared with gasoline-powered cars, vehicles fueled with electricity from renewable sources could cut air pollution-related deaths by 70 percent, according to a new study, which noted that air pollution is the country’s greatest environmental health threat.

Published this week in the Proceedings of the National Academy of Sciences, the study’s researchers examined the impact of various vehicle energy sources on the concentrations of two types of air pollutants known to affect human health: particulate matter and ground-level ozone. Previous research has found that air pollution causes 200,000 premature deaths in the U.S. each year and vehicle emissions are the most significant contributor. For fine particulate matter alone, the Centers for Disease Control and Prevention cites studies finding a 15 percent decrease in the risk of heart attack deaths with every decrease of 10 micrograms per cubic meter of particulate matter. Ground-level ozone can trigger a number of adverse health events, such as chest pain and breathing difficulty, and is particularly dangerous for people already living with respiratory illnesses such as asthma.

In the recent journal study, researchers studied a variety of alternative fuels in comparison to gasoline, including liquid biofuels, diesel and compressed natural gas used to fuel internal combustion engines as well as electricity from a range of traditional and renewable sources. Using state-of-the-art simulations and modeling to estimate the changes in pollutants, researchers then used population data as well as major epidemiological studies to estimate the effect on human mortality. And in addition to analyzing the pollution that came from the vehicles, the study also considered the emissions emitted during the production of the fuels or electricity on which the vehicles run. They found that switching to vehicles that run on electricity derived using natural gas results in large health benefits, while vehicles that run on corn ethanol or are powered by coal-based or “grid average” electricity are worse for health. In fact, the study found that switching from gasoline to corn ethanol or grid average electricity would increase air pollution-related deaths by 80 percent or more.

Study authors Christopher Tessum, Jason Hill and Julian Marshall write:

Our assessment of the life cycle air quality impacts on human health of 10 alternatives to conventional gasoline vehicles finds that electric vehicles powered by electricity from natural gas or wind, water, or solar power are best for improving air quality, whereas vehicles powered by corn ethanol and (electric vehicles) powered by coal are the worst. This work advances the current debate over the environmental impacts of conventional versus alternative transportation options by combining detailed spatially and temporally explicit emissions inventories with state-of-the-science air quality impact analysis using advanced chemical transport modeling. Our results reinforce previous findings that air quality-related health damages from transportation are generally comparable to or larger than climate change-related damages.

The study found that human health impacts range from 230 deaths per year for the scenario considering wind, water and solar-powered electric vehicles (including the emissions from producing the energy source) to 3,200 annual deaths for the coal-powered electric vehicle scenario. When compared to gasoline, transportation scenarios that significantly decreased air quality-related health effects included gasoline hybrid vehicles, which resulted in a 30 percent decrease, and electric vehicles powered by natural gas or wind, water and solar, which resulted in a 50 percent and 70 percent decrease, respectively. Those scenarios that resulted in increased health damages when compared to gasoline included corn ethanol, an 80 percent increase, and electric cars powered by grid average or coal electricity, at 200 percent and 350 percent, respectively.

The authors write that while much of the research on life cycle environmental impacts zeros in on greenhouse gas emissions and climate change, it’s critical to consider the impact of alternative fuels on air quality and thus human health as well. For example, the study noted a six-fold difference between the most-polluting and least-polluting methods for generating electricity for electric vehicles when air quality impacts are considered along with climate impacts, compared to when climate impacts are considered on their own. The authors also write that the study supports the inclusion of human health effects when analyzing the impacts of transportation choices, as the economic burden of adverse health effects can be as great, or greater than, the effects on climate change. Of course, the authors wrote that their study “should not be taken as a final statement” and that further research is needed.

“Instead, these results can be seen as an indication of how light-duty transportation fuels could shift to reduce or increase pollution, and as an encouragement into the research of less polluting, more sustainable transportation options for the future,” they concluded.

To read a full copy of the study, visit the Proceedings of the National Academy of Sciences.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for more than a decade.