Fast Facts
- Reduction: Research analyzing over 1,700 California neighborhoods found a direct, measurable link between increased EV ownership and lower nitrogen dioxide levels.
- Reduced Particulate Matter: Beyond eliminating tailpipe emissions, EVs significantly reduce, or in some cases eliminate, brake dust, which is a major source of air pollution.
- Proven Impact: The study published in The Lancet Planetary Health validated this data against actual atmospheric conditions, proving the environmental benefit is happening in real-time.
- Cleaner Grids, Cleaner Air: As energy grids shift toward renewable sources, the net emissions from operating EVs continue to decrease.
A New Study Measures EV Impact in Real Time
Using Satellite data, Keck School of Medicine at USC researchers have now reported the first significant decrease in nitrogen dioxide (NO2) levels in California due to the use of zero-emissions vehicles. It is believed that though California is number one in EV sales (1.3 million currently) all states can benefit greatly from the use of green cars.
This new study pulled high-res satellite data from a Tropospheric Monitoring Instrument (TROPOMI) to measure how nitrogen dioxide in the air absorbs and reflects sunlight. The data was used to find out the annual average levels of NO2 in California cities and neighborhoods from 2019 to 2023.
Data from California’s Department of Motor Vehicles accounted for the number of zero-emission vehicles (both EVs and PHEVs) registered in each targeted neighborhood. The data collected showed that for every 200 EVs registered in the Golden State between 2019 and 2023, NO2 levels dropped by 1.1 percent. Over the study period, electric vehicle market shares advanced from 2 percent to 5 percent of all light-duty vehicles in California.
Why the Health Impact Matters
“This immediate impact on air pollution is really important because it also has an immediate impact on health,” said Erika Garcia, PhD, MPH, assistant professor of population and public health sciences at Keck School of Medicine. She is also the study’s senior author. “We know that traffic-related air pollution can harm respiratory and cardiovascular health over both the short and long term.”
Cleaner air benefits are part of the broader story about why drivers are switching, and here’s a look at how EV ownership is reshaping the used market ➜
The study explains that a typical neighborhood gained anywhere between 18 and 839 electric vehicles during the study period. According to the study’s lead author, Sandrah Eckel, PhD, “These finding show that cleaner air isn’t just a theory—it’s already happening in communities across California. We’re not even fully there in terms of electrifying, but our research shows that California’s transition to electric vehicles is already making measurable differences in the air we breathe.”
It should be noted that the researchers excluded data from the year 2020 entirely due to a decline in NO2 due to pandemic-related contributing factors. In other words, people didn’t drive as much during COVID. “We tested our analysis in many different ways, and the results consistently support our main finding,” Ericka Garcia tells us.
What the Numbers Actually Show
For the analysis, the researchers divided California into 1,692 neighborhoods, using a geographic unit similar to zip codes. DMV records denoted the number of electric cars and plug-in hybrids in each neighborhood. High-resolution satellite sensors provided daily global measurements of NO2, and other pollutants and the study analyzed the average NO2 levels in each California neighborhood from 2019 to 2023.
So, the science tells us that for every 200 EVs added to the mix of vehicles, the report shows a reduction of NO2 levels dropping by 1.1 percent. The more EVs we drive, the less air pollution we will likely breathe.
The study was funded in part by the National Institutes of Health and was recently published in The Lancet Planetary Health.
Electric Cars to Make Up a Quarter of Global Sales in 2025
Global EV adoption continues rising, reinforcing long-term environmental momentum
Read More ➜
New and Used EVs Are Now More Affordable Than Ever
Lower prices and expanding inventory are accelerating EV adoption in key markets
Read More ➜
Hybrid Vehicles Claim Bigger Market Share in 2025
Hybrid growth shows electrification is expanding across multiple pathways
Read More ➜
