EVs Already Cutting Air Pollution in California, Satellite Study Shows

Using high-resolution satellite data, the team reported the first statistically significant drop in nitrogen dioxide pollution linked directly to zero-emissions vehicles, showing that cleaner transportation is delivering real benefits today, according to the study by researchers at the Keck School of Medicine of USC.

The study, published in The Lancet Planetary Health, analysed changes in air pollution levels between 2019 and 2023 as more Californians switched to zero-emissions vehicles, including fully electric and plug-in hybrid cars.

Researchers found that for every 200 electric vehicles added in a neighborhood, nitrogen dioxide levels fell by about 1.1 per cent.

Nitrogen dioxide is a harmful pollutant produced mainly by burning fossil fuels and is known to trigger asthma, bronchitis, heart disease and strokes.

While electric vehicles are often promoted as a way to fight climate change in the long run, this research shows they are also making the air cleaner in the short term.

Earlier studies using ground-based air monitors suggested a link between electric vehicle adoption and lower pollution, but limited coverage made the results uncertain.

By using satellite data from NASA's TROPOMI instrument, which measures air pollutants across large areas daily, the USC team was able to track changes in nearly every neighborhood in California.

The researchers divided the state into 1,692 neighborhood-sized areas and compared electric vehicle registration data from the California Department of Motor Vehicles with annual nitrogen dioxide levels.

Over the five-year period, a typical neighborhood added around 272 zero-emissions vehicles. Many areas saw even bigger increases, leading to noticeable improvements in air quality.

Senior author Dr. Erika Garcia said the findings are important because air pollution affects health almost immediately.

Traffic-related pollution can harm the lungs and heart both in the short and long term, making reductions especially meaningful for community well-being.

Lead author Dr. Sandrah Eckel added that even though electric vehicles still make up a small share of all cars in California, their impact is already measurable.

During the study period, zero-emissions vehicles grew from about 2 per cent to 5 per cent of all light-duty vehicles -- showing that much more improvement is possible as adoption continues.

The study also highlights the power of satellite technology to track air pollution worldwide, opening new opportunities to study the environmental impact of clean energy policies.

The research was supported in part by the National Institutes of Health and NASA, with contributions from scientists across USC, George Washington University, UC San Diego and community partners in Los Angeles.

- IANS