Gas Leaks

In 2021, Geodelphia contracted with Gas Safety Inc. of Massachusetts to measure gas leaks along 10% of the streets in the City of Philadelphia.  The study was funded by Sierra Club’s Southeastern PA Group. This is an overview of the Philadelphia area, showing the relative density of methane in the air The darker the purple, the higher the concentration:

The Picarro G2301 Cavity Ringdown Spectrometer (CRDS), used in this survey, measures methane in parts per billion (PPB) each second and “tags” each methane reading with a GPS coordinate, providing information to map methane concentrations across any locus.  The CRDS has been very useful in educating the public, elected officials and utility regulators about the problems associated with gas pipeline distribution system leakage. 

As an example, here are the readings for a site at 5th and Fitzwater Streets in South Philly: Figure #1 is the CRDS reading.  Figure #2 is the background methane level – what is in our air “naturally,” and #3 is the CRDS reading minus the background.

Also at 5th and Fitzwater, in 2021 Melissa Ostroff captured this video of methane leaking from a manhole near her home. She was using an Optical Gas Imaging Camera for an Earthworks project helping communities document methane  leaks. Click on the video to link to her article about it (Philadelphia Citizen, 12/20/2021).