Atmospheric methane emissions correlate with natural gas consumption from residential and commercial sectors in Los Angeles

Legislation in the State of California mandates reductions in emissions of short-lived climate pollutants of 40% from 2013 levels by 2030 for CH4. Identification of the sector(s) responsible for these emissions and their temporal and spatial variability is a key step in achieving these goals. Here, we determine the emissions of CH4 in Los Angeles (LA) from 2011-2017 using a mountain-top remote sensing mapping spectrometer. We show that the pattern of CH4 emissions contains both seasonal and non-seasonal contributions. We find that the seasonal component peaks in the winter and is correlated (R2=0.58) with utility natural gas consumption from the residential and commercial sectors and not from the industrial and gas-fired power plant sectors. The non-seasonal component is (22.9  1.4) Gg CH4/month. If the seasonal correlation is causal, about (1.4  0.1) % of the commercial and residential natural gas consumption in LA is released into the atmosphere.