During his State of the Union address this week, President Joe Biden highlighted tax credits for EVs as a key plank in his strategy to corral climate change. Transportation is the largest source of greenhouse gas emissions in the United States, and electrifying cars and trucks is a key step in reducing their impact on the planet’s temperature. But switching from hydrocarbons to electrons has immediate benefits for the environment too, which in turn can improve public health.
It makes sense that an electric car would lead to less air pollution than a car that burns gasoline. No engine, no combustion byproducts: carbon monoxide, sulfur oxides, nitrogen oxides, aldehydes, and so on. When inhaled, these chemicals can lead to high blood pressure, worsen emphysema, and trigger asthma attacks. Air pollution contributes to as many as 200,000 deaths per year in the United States. By some estimates, the health and economic benefits of avoided air pollution on their own are enough to justify the transition to clean energy.
Swapping internal combustion cars and trucks for electric vehicles would lessen these health problems. And according to a new study, it doesn’t even take very many EVs to have a measurable benefit.
A study published earlier this month in the journal Science of the Total Environment found that in California, every 20 zero-emissions vehicles per 1,000 people in a given zip code led to a 3.2 percent drop in the rate of emergency room visits due to asthma.
What’s interesting here is that the researchers found this by studying actual air pollution levels and health outcomes rather than using models and simulations. These are not hypothetical benefits in the future; they’re happening now.
“We really wanted to use real-world data, as real-world as possible, to see if we saw health impacts and air quality impacts,” said co-author Sandy Eckel, a biostatistician at the University of Southern California.
Health is often framed as a co-benefit of the transition toward cleaner energy, but the study’s findings highlight how even for a massive global problem like climate change, some individual decisions can have an impact right away. The findings also showed, however, that EVs are an expensive way to address pollution and their benefits skew toward wealthier communities that can afford them. Often, that leaves communities with lesser means and more pollution in the dust.
EVs can benefit your health, if you can afford them
Eckel and her team looked at 1,200 zip codes across the Golden State between 2013 and 2019. They tracked electric vehicle registrations and local measurements of nitrogen dioxide, a pollutant produced by conventional engines that can cause breathing problems on its own and trigger the formation of other pollutants like ozone and particulate matter.
The team controlled for long-term improvements in air quality. California has some of the strictest air quality rules in the US and has led the country in pushing cars and trucks to emit less, so pollution in general has declined over time.
During the seven-year study period, the average number of zero-emissions vehicles per 1,000 people in a zip code increased from 1.4 to 14.7. As EV penetration grew, ER visits dropped.
“This study adds to a strong body of research that we’ve already seen that shows the benefits of electric vehicles,” said Kathy Harris, senior advocate for clean vehicles at the Natural Resources Defense Council, who was not involved in the experiment.
But EV adoption wasn’t spread evenly across the state.
“There’s a lot of different social demographics there as well, and as part of the analytic approach, we did adjust for some influences of socioeconomic status,” said Erika Garcia, another co-author and a public health researcher at USC.
In particular, the researchers looked at education levels, which served as a proxy for wealth in a community. Across California zip codes, the share of adults with at least a bachelor’s degree ranged from 1.1 percent to 87.1 percent. In communities with 17.1 percent of adults with bachelor’s degrees, the 25th percentile for education, the number of zero-emissions vehicles increased by 0.7 every year per 1,000 residents on average. At the 75 percentile for education, 47.2 percent of adults with bachelor’s degrees, the average annual increase in electric cars was 3.55, about five times higher.
Higher educational attainment is strongly linked to higher incomes, which then make it easier to afford EVs. The average new car in the US last year cost around $48,000, while the average new electric car cost $66,000.
Taken together, the findings reveal that the air quality improvements from switching to electric cars skew toward wealthier communities. That gap poses a tricky problem for public health because lower-income areas often face a higher baseline level of air pollution and its associated health problems.
“It’s not surprising given how new technologies tend to infiltrate new populations,” said Garcia. “But it’s highlighting the need to ensure that these public health co-benefits are going to be distributed equally and equitably across the population.”
Electric cars aren’t the only way to improve air quality
Closing the EV adoption gap can pose a political challenge, however. Last November, California voters rejected a ballot measure that would raise taxes on wealthy residents to subsidize EVs for low-income and disadvantaged communities.
But EVs aren’t the only route to reducing air pollution, and in many cases, they aren’t the best option. Electric cars and trucks are generally heavier than their gasoline counterparts, which can lead to more dust pollution from rubber and roads even as they eliminate exhaust pollution. Some of the largest EVs are actually worse for the climate than smaller combustion vehicles. Giant SUVs like the Hummer EV require more energy to move. Since the bulk of the US power grid still runs on fossil fuels, the carbon footprint of a big EV per mile can be larger than that of a tiny gasoline car.
So spreading the benefits of improved air quality to the most vulnerable people requires looking beyond the tailpipes of personal cars, Harris said. Electrifying public transportation, trucks, and fleet vehicles, which are often routed through low-income communities, are also important tactics. And making it easier to live without a car at all might yield the biggest health benefits. Last year, the California legislature passed a $1,000 tax credit for low-income residents who don’t own a car.
Still, EVs are charging ahead. In 2022, they accounted for 5.8 percent of new vehicle sales in the United States, up from 3.1 percent in 2021. California, the largest car market in the country, has already committed to ending the sales of all fossil-fuel powered vehicles by 2035. Major manufacturers like General Motors have committed to going all-electric while a new crop of full-electric carmakers is starting to emerge.
These shifts will eventually trickle down to those with less money, but to save more lives, the transition will have to speed up.