Power plants, water treatment facilities and even cattle in Chino are just a few of the things creating methane hot spots around Southern California, according to a new study out from the University of California, Irvine.
The study looked at areas around the Los Angeles Basin emitting the highest levels of methane, which scientists have linked to climate change. Using a special vehicle outfitted with GPS, a rooftop sampling mast and spectrometers, researchers drove for miles around Southern California and took air samples continuously.
They monitored levels of methane, ethane, carbon dioxide and carbon monoxide. Using the data, they were able to identify 213 hot spots in locations across L.A., Riverside and Orange counties.
While the study was conducted before the Porter Ranch gas leak happened this past October, the study's authors say they’re hopeful Southern California Gas Company will use the findings to help meet Gov. Jerry Brown and the Air Resource Board’s orders that they remove as much methane from the air as was emitted during the leak.
Are you blown away by this UC Davis researcher’s findings about methane at Porter Ranch?
Francesca Hopkins: That certainly has been far bigger than any magnitude of what we’ve seen throughout the L.A. Basin.
Now, this project you started before this whole Porter Ranch thing — tell us about it.
It’s been known for a couple years now that we observe higher methane emissions when we do atmospheric measurements in the L.A. Basin than what’s accounted for in the state’s methane inventory. There’s been a lot of work done in the past about that, but nobody had looked at the spatial patterns of methane. So that’s what we set out to do. We built a mobile lab system that actually measured air in real time and measured the methane and ethane concentrations in the air to try to locate where these methane emissions are coming from.
Now, landfills, don’t they have methane capturing systems so that this doesn’t — at least theoretically — spew into the air?
That’s right. Most of the landfills in the L.A. basins have methane capture systems. But what we found is that their effectiveness probably varies greatly. We weren’t able to do really facilities-specific measurements, but from our observations, we observed methane emissions from all the landfills that we measured — including landfills that have been closed, so no new trash has been added for up to 50 years [but the landfills] are still emitting methane despite the presence of theses mitigating systems.
Does that pose any health challenges for people who live, you know, close to or downwind from landfills?
We were only measuring methane in this study, so I can’t speak to the more harmful pollutants, but the levels of methane that we measured in the atmosphere were thousands of times below the levels that become dangerous for the explosive limit.
But still collectively pose a greenhouse gas climate concern.
Absolutely. Other work has shown that there’s at least 50 percent more emissions than what the state is accounting for.
Fifty percent more methane?
Right. Other studies have shown that in the past, and our work is really just trying to pinpoint what are those locations. That’s really the first step we need towards taking action to mitigate these leaks.
What was the biggest surprise location where you saw methane released?
I think one of the big surprises is that we see methane leaking from compressed natural gas fueling stations. It’s a system that we have in place to fuel these vehicles that actually burn much more cleanly than traditional vehicles, but it looks like some components of these stations are leaking methane into the atmosphere. So that was a big surprise also, because that’s not being accounted for in most greenhouse gas emissions inventory.
Have you had direct contact with state regulators on this for them to follow up based on your research?
No, we haven’t yet, but we’re hoping that now [that] the results are published that maybe we can build that collaboration.
Francesca Hopkins, post-doctoral fellow at the NASA Jet Propulsion Laboratory and lead author of the UCI study which mapped methane hot spots across the L.A. Basin
Note: This interview has been edited for clarity.
This story has been updated.