By Edward McAllister
NEW YORK (Reuters) - Google Inc's Street View cars have captured the world's roads, highways and back alleys for years. Now they are being used for something entirely different: detecting the thousands of natural gas leaks blighting major U.S. cities.
Google cars fit with air monitors have taken millions of readings along the streets of Boston, New York and Indianapolis over the past two years as part of a program run by the non-profit Environmental Defense Fund to help reduce methane emissions.
The results, announced by the fund on Wednesday, reveal how common leaks are in highly populated areas that until now have not been quantified. In central Boston, leaks were discovered every few blocks.
While the leaks were small and did not appear hazardous, they have prompted concerns about methane whose global warming impact is 20 times greater than carbon dioxide, according to the U.S. Environmental Protection Agency. The leaks also raise questions about the safety of old pipelines carrying natural gas in growing volumes across North America.
A natural gas pipeline leak caused an explosion in the New York City neighborhood of Harlem in March this year, leveling two buildings and killing eight people.
The data, collected through air analysis systems, showed thousands of leaks in areas like Boston and New York's Staten Island that rely on older, corroded cast iron pipelines. But in Indianapolis, where newer, plastic pipes have been installed, almost no leaks were detected.
"Until now, these smaller leaks have not been a priority in most places. Yet we can see from these maps just how much they can add up," Mark Brownstein, EDF chief counsel for natural gas, said in a statement.
Methane leaks have previously been detected, but this new method, which involved 15 million readings taken over thousands of miles, revealed the volume of gas leaking in each area, said EDF's chief scientist, Steven Hamburg. It could be a step to detecting total methane emissions from a given city, he said.
The EDF said other cities will be added to the program, but did not elaborate.
The findings come as President Obama makes carbon emissions a key issue of his second term.
U.S. production of natural gas, which is mostly methane, is on the rise due to a drilling boom. The network of pipelines carrying the fuel is expanding rapidly.
"This kind of technology and data offers valuable insights," said Susan Fleck, vice president of pipeline safety for National Grid, which supplies Boston and was also involved in the study.
"We are taking action, accelerating natural gas pipeline replacement to reduce leaks."
(Reporting By Edward McAllister; Editing by Richard Chang)