A team of researchers at the Keck School of Medicine of USC has now begun documenting the actual impact of electric vehicle adoption in the first study, using real-world data to link electric vehicles, air pollution and health. Using publicly available datasets, the researchers analyzed a “natural experiment” taking place in California as the state’s residents rapidly transitioned to electric vehicles, or lightweight zero-emission vehicles (ZEVs). The results have just been published in the journal Science of the Total Environment.
The team compared data on total statewide ZEV registrations, air pollution levels and asthma-related emergency room visits from 2013 to 2019. As ZEV adoption increases within a given ZIP code, local air pollution levels and emergency room visits decrease.
“When we think about actions related to climate change, it’s usually on a global scale,” said Dr. Erika Garcia, assistant professor of population and public health sciences at the Keck School of Medicine and the study’s lead author, adding. , “However, the idea that changes made at the local level can improve the health of your own community can be a powerful message to the public and policymakers.”
The researchers also found that while total ZEV volume has increased over time, adoption has been much slower in low-resource zip codes — what the researchers call an “adoption gap.” This disparity suggests an opportunity to restore environmental justice in communities disproportionately affected by pollution and related health problems.
“Talking about the health effects of climate change can be challenging because they feel so scary,” said Sandrah Eckel, Ph.D., associate professor of population and public health sciences at the Keck School of Medicine and the study’s senior author. Moving to climate change mitigation and adaptation, these results show that transitioning to ZEVs is a critical part of this.”
Health and Climate Benefits
To study the impact of EV adoption, the research team analyzed and compared four different datasets. First, they took data from the California Department of Motor Vehicles for ZEVs (including pure electric, plug-in hybrid, and hydrogen fuel cell vehicles) and tabulated the total number of registrations per zip code for each year between 2013 and 2019 .
They also obtained data on nitrogen dioxide (NO2) levels, a traffic-related air pollutant, and asthma-related emergency room visits at the ZIP code level from the US Environmental Protection Agency’s air monitoring sites. Asthma is one of the health problems long associated with air pollutants like nitrogen dioxide, which can also cause and exacerbate other respiratory conditions, as well as problems with the heart, brain and other organ systems.
Finally, the researchers calculated the percentage of adults in each zip code with a bachelor’s degree. Educational attainment is often used as an indicator of neighborhood socioeconomic status.
At the zip code level, each additional 20 ZEVs per 1,000 people was associated with a 3.2 percent decrease in asthma-related emergency department visits and a small decrease in nitrogen dioxide levels. From 2013 to 2019, the average ZEV across the state’s ZIP codes increased from 1.4 to 14.6 vehicles per 1,000 people. ZEV adoption is significantly lower in less educated ZIP codes. For example, a ZIP code with 17% of the population with a bachelor’s degree would increase by an average of 0.70 ZEV per 1,000 people per year compared to 47% of the population with a bachelor’s degree.
Past research has shown that underserved communities, such as low-income neighborhoods, tend to face higher levels of pollution and related respiratory problems than affluent areas. These communities could benefit greatly if ZEVs replaced gasoline-powered vehicles in these communities.
“If ongoing research supports our findings, we want to ensure that communities disproportionately burdened by traffic-related air pollution actually benefit from this type of climate mitigation,” Garcia said.
While climate change is a huge health threat, mitigating it presents a huge public health opportunity, Eckel said. As one of the first studies to quantify the real-world environmental and health benefits of ZEVs, the study could help demonstrate the power of such mitigation measures, including potential reductions in healthcare utilization and spending.
The findings are promising, but many questions remain, Garcia said. Future studies should consider other impacts of ZEVs, including emissions related to brake and tire wear, extraction of manufacturing materials, and disposal of used vehicles. The researchers also hope to study other types of pollutants and other types of vehicles, in addition to conducting follow-up studies on the impact of the state’s growing share of ZEVs.
Going forward, Eckel said, transitioning to ZEVs is only part of the solution. Shifting to public transit and active transportation, including walking and cycling, are other important ways to improve the environment and public health.
First published date: Feb 3, 2023 at 08:25 AM CST