If the energy used to power electric vehicles comes from traditional resources such as burning coal rather than renewable sources, driving battery-powered cars will pollute the air more than cars powered by fossil fuels. 

That increased pollution would result in more worldwide deaths, said researchers who published their findings in the Proceedings of the National Academy of Sciences.

Over 100,000 people are killed each year by fine particulate matter and ground-level ozone. If coal-powered electric cars accounted for ten percent of the vehicle-miles expected to be driven in America in 2020, an extra 3,000 deaths would result.

"Overall, the research shows that electric cars are cleaner than those that rely on internal-combustion engines only if the power used to charge them is also clean."

Whether electric cars are an environmentally sound solution to individual transport may vary according to country. In nations like France, which relies heavily on nuclear power, a fleet of electric cars represents a sustainable option. But in China, which is eager to promote electric cars and while relying on coal-fired power plants, the option would pose a threat to public health.

As theoretical physicist Michio Kaku explains in his Big Think interview, although burning fossil fuels "pollutes like hell," they remain more efficient than batteries:

Read more at the Economist

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