A team of researchers from USC’s Keck School of Medicine has begun to document the real impact of electric vehicle adoption in the first study to use real-world data to correlate electric cars, air pollution and health. Using publicly available data (ZEVs), the researchers analyzed a ‘natural experiment’ taking place in California as people quickly converted to electric cars, or light-duty zero-emission vehicles. The findings were just published in Science of Total Environment. Between 2013 and 2019, researchers analyzed data on overall ZEV registrations, air pollution levels and asthma-related emergency department visits across the state. Local air pollution levels and emergency department visits decreased as ZEV adoption increased within a given zip code.
“When we think about action related to climate change, it is often on a global scale,” said Erika Garcia, PhD, MPH, assistant professor of population and public health sciences at the Keck School of Medicine and lead author of the study. Said. , adding, “But the idea that making changes at the local level can improve the health of your own community can be a powerful message to the public and policy makers.”
The researchers also found that as total ZEVs increased over time, adoption was significantly slower in low-resource zip codes – what the researchers refer to as the ‘adoption gap’. This disparity points to an opportunity to restore environmental justice in communities that are disproportionately affected by pollution and related health problems.
“Talking about the effects of climate change on health can be challenging because they can feel so scary,” said Sandra Eckel, MD, an associate professor of population and public health sciences at the Keck School of Medicine and senior author of the study. “We are excited about shifting the conversation towards climate change mitigation and adaptation, and these results suggest that transition to ZEVs is an important part of this,” he said.
To study the effects of electric vehicle adoption, the research team analyzed and compared four different datasets. First, they obtained data on ZEVs (which includes battery electric, plug-in hybrid and hydrogen fuel cell cars) from the California Department of Motor Vehicles and calculated the total number registered in each zip code for each year between 2013 and 2019. tabulated.
They obtained data from US Environmental Protection Agency air monitoring sites on levels of nitrogen dioxide (NO2), traffic-related air pollutants, and ZIP code-level asthma-related visits to the emergency room.
Asthma has long been one of the health concerns associated with air pollutants such as NO2, which can cause and exacerbate other respiratory diseases as well as problems with the heart, brain and other organ systems.
Finally, the researchers calculated the percentage of adults in each zip code who had a bachelor’s degree. Levels of educational attainment are often used as indicators of a neighborhood’s socioeconomic status.
At the ZIP code level, for every additional 20 ZEVs per 1,000 people, there was a 3.2 percent drop in the rate of asthma-related emergency visits and a small suggestive reduction in NO2 levels. The average ZEV per zip code in the state increased from 1.4 to 14.6 per 1,000 people between 2013 and 2019.
Zip codes with lower levels of educational attainment had significantly lower ZEV adoption rates. For example, a ZIP code with 17 percent of the population holding a bachelor’s degree grew 47 percent, with an annual increase of 3.6 ZEV per 1,000 people compared to an average annual increase of 0.70 ZEV per 1,000 people Was. of the population holding a bachelor’s degree.
Previous research has shown that low-income neighborhoods such as under-served communities face worse pollution and associated respiratory problems than more affluent areas. If ZEVs replace gas-powered cars in those areas, they could be of great benefit.
“As ongoing research supports our findings, we want to be sure that communities that are most affected by traffic-related air pollution are actually benefiting from this climate mitigation effort,” Garcia said.
Eckel said, while climate change is a massive health threat, mitigating it offers a massive public health opportunity. As one of the first studies to quantify the real-world environmental and health benefits of ZEVs, the research could help demonstrate the power of this mitigation measure, which potentially includes reduced health care use and expenditure.
The findings are promising, Garcia said, but many questions remain. Future studies should consider additional impacts of ZEVs, including emissions related to brake and tire wear, mining of materials for their manufacture, and disposal of old cars. The researchers also hope to study additional types of pollutants and other classes of vehicles, in addition to conducting a follow-up study of the effects of the increased share of ZEVs in the state.
Eckel said that going forward, transitioning to ZEVs is just part of the solution. Adopting public transportation and active transportation, including walking and biking, are other major ways to promote the environment and public health.