December 13, 2012 By Creighton Welch
Natural gas leaks can cause serious problems in our cities -- on Dec. 11, for instance, a 20-inch Columbia Gas transmission line exploded in Sissonville, W. Va., and destroyed four homes and essentially cooked a section of the interstate.
To see what Boston had going on in its natural gas pipelines, a team of scientists set out to map and measure leaks throughout the city. After all was said and done, they spent a month driving 785 miles -- and they discovered 3,356 methane leaks.
Jackson helped lead the study along with Nathan Phillips, associate professor at Boston University’s Department of Earth and Environment. During the month they spent measuring, they drove about 20 miles-per-hour down each street, sometimes in both directions, using a tool called a Picarro G2301 Cavity Ring-down Spectrometer.
It’s a fast-response methane analyzer that measures methane concentrations higher than 2 parts per million (the normal amount in the air). They combined the methane measurement device with a high-resolution GPS, and loaded those in the car. The devices were connected so as they measured methane concentrations, they also mapped where they were. This information was then loaded into a GIS file to produce a map of the measurements.
When they found large methane leaks that could pose an immediate explosion threat, they stopped and gathered an air sample to analyze the chemistry to determine if the leak was coming from a sewer or landfill, or if it was pipeline gas. A vast majority of the leaks were from pipelines. While all leaks were measured and mapped, the team called in six pipeline leaks they felt were explosion risks, which the utility companies then fixed.