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Car Emissions

August 23, 2016

Gasoline-powered cars run cleaner than ever, but still belch toxins when they start.


ian mcwilliams CC BY 2.0, via flickr

California leads the U.S. in emissions standards, but even newer gasoline-powered vehicles still produce the most air pollution during the first few minutes after starting up. (Ian McWilliams/CC BY 2.0, via flickr)


A car’s dirtiest minute. I’m Bob Hirshon and this is Science Update.

Forty percent of US residents live in areas where air pollution reaches unhealthy levels. At a meeting of the American Chemical Society, UC Berkeley atmospheric chemist Greg Drozd, reported that Volatile Organic Compounds, or VOCs, from cars are big contributors. He and his colleagues found that while new cars pollute the least, all of them produced the most VOCs in the first minute after a “cold start,” after the car had been sitting for hours.

GREG DROZD (University of California, Berkeley):

A new vehicle, a clean vehicle: 95% plus of their total VOC emissions would be due to the cold start.


He says that’s because catalytic converters, which reduce VOCs, are ineffective until they’ve warmed up. So further reductions in emissions will rely on new technologies that target that first minute after starting. I’m Bob Hirshon, for AAAS, the science society.

Story by Bob Hirshon