Major U.S. cities may be leaking far more methane into the atmosphere than government estimates suggest. New measurements found that up to twice as much gas is being released from six cities on the East Coast — Washington, D.C.; Philadelphia; Boston; New York; Providence, R.I.; and Baltimore — than estimates recorded by EPA. Their combined methane emissions are higher than those at some of the nation’s biggest natural gas production centers, including the Four Corners region and the Bakken Shale in the Dakotas. The measurements suggest that the cities’ combined methane emissions come to about 8.9 teragrams — or 890,000 metric tons — each year.
— source scientificamerican.com | Jul 23, 2019