A new study that used a mountaintop sensor to measure air pollution in the Los Angeles Basin found emissions of methane, a potent greenhouse gas, are up to 61% higher than government estimates.
The study published Monday in the journal Atmospheric Chemistry and Physics, is the latest to reveal official emissions inventories that underestimate the amount of the planet-warming pollutant being released into the atmosphere.
Scientists detected hot spots near major landfills, in Pasadena and across a 15-mile-wide area straddling eastern L.A. County and northern Orange County. The methane detected probably came from a variety of sources, including natural gas pipelines, vehicles, waste facilities, farms and naturally occurring seeps like the La Brea Tar Pits, they said.
California air quality regulators, who participated in the study with scientists at NASA/JPL, Caltech and the University of Michigan, said it was part of a longstanding effort to better understand where methane is being released.
Bart Croes, research director for the Air Resources Board, said the agency’s own studies have also shown higher than previously estimated methane emissions. Later this year, the agency expects to release an improved statewide methane inventory and a new plan to control the pollutant.
Carbon dioxide from burning fossil fuels is the biggest contributor to climate change, but methane is many times more effective at trapping heat in the atmosphere. Scientists are uncertain about the amount of methane being released each year from major sources like landfills, dairy farms, and oil and gas operations.
http://www.latimes.com/science/la-me-methane-emissions-20150114-story.html