August 9, 2012 Traffic in Los Angeles, Calif. (Credit: Puck90
via Flickr Creative Commons) In California’s Los Angeles Basin,
levels of some vehicle-related air pollutants have decreased by
about 98 percent since the 1960s, even as area residents now
burn three times as much gasoline and diesel fuel. Between 2002
and 2010 alone, the concentration of air pollutants called
volatile organic compounds (VOCs) dropped by half, according to
a new study by NOAA scientists and colleagues, published in the
Journal of Geophysical Research yesterday. “The reason is
simple: Cars are getting cleaner,” said Carsten Warneke, Ph.D.,
a NOAA-funded scientist with the Cooperative Institute for
Research in Environmental Sciences (CIRES) at the University of
Colorado Boulder. VOCs, primarily emitted from the tailpipes of
vehicles, are a key ingredient in the formation of ground-level
ozone which, at high levels, can harm people’s lungs and damage
crops and other plants. The magnitude of the drop in VOC levels
was surprising, even