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Title: Top-down methane emissions estimates for the San Francisco Bay Area from 1990 to 2012

Abstract

Methane is a potent greenhouse gas (GHG) that is now included in both California State and San Francisco Bay Area (SFBA) bottom-up emission inventories as part of California's effort to reduce anthropogenic GHG emissions. Here we provide a top-down estimate of methane (CH4) emissions from the SFBA by combining atmospheric measurements with the comparatively better estimated emission inventory for carbon monoxide (CO). Local enhancements of CH4 and CO are estimated using measurements from 14 air quality sites in the SFBA combined together with global background measurements. Mean annual CH4 emissions are estimated from the product of Bay Area Air Quality Management District (BAAQMD) emission inventory CO and the slope of ambient local CH4 to CO. The resulting top-down estimates of CH4 emissions are found to decrease slightly from 1990 to 2012, with a mean value of 240 ± 60 GgCH4 yr⁻¹ (at 95% confidence) in the most recent (2009–2012) period, and correspond to reasonably a constant factor of 1.5–2.0 (at 95% confidence) times larger than the BAAQMD CH4 emission inventory. However, we note that uncertainty in these emission estimates is dominated by the variation in CH4:CO enhancement ratios across the observing sites and we expect the estimates could represent amore » lower-limit on CH4 emissions because BAAQMD monitoring sites focus on urban air quality and may be biased toward CO rather than CH4 sources.« less

Authors:
ORCiD logo;
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
2325268
Alternate Identifier(s):
OSTI ID: 1208641
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article: Published Article
Journal Name:
Atmospheric Environment (1994)
Additional Journal Information:
Journal Name: Atmospheric Environment (1994) Journal Volume: 107 Journal Issue: C; Journal ID: ISSN 1352-2310
Publisher:
Elsevier
Country of Publication:
United Kingdom
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; methane emissions; emissions inventory; greenhouse gas; inventory verification; top-down estimates

Citation Formats

Fairley, David, and Fischer, Marc L. Top-down methane emissions estimates for the San Francisco Bay Area from 1990 to 2012. United Kingdom: N. p., 2015. Web. doi:10.1016/j.atmosenv.2015.01.065.
Fairley, David, & Fischer, Marc L. Top-down methane emissions estimates for the San Francisco Bay Area from 1990 to 2012. United Kingdom. https://doi.org/10.1016/j.atmosenv.2015.01.065
Fairley, David, and Fischer, Marc L. 2015. "Top-down methane emissions estimates for the San Francisco Bay Area from 1990 to 2012". United Kingdom. https://doi.org/10.1016/j.atmosenv.2015.01.065.
@article{osti_2325268,
title = {Top-down methane emissions estimates for the San Francisco Bay Area from 1990 to 2012},
author = {Fairley, David and Fischer, Marc L.},
abstractNote = {Methane is a potent greenhouse gas (GHG) that is now included in both California State and San Francisco Bay Area (SFBA) bottom-up emission inventories as part of California's effort to reduce anthropogenic GHG emissions. Here we provide a top-down estimate of methane (CH4) emissions from the SFBA by combining atmospheric measurements with the comparatively better estimated emission inventory for carbon monoxide (CO). Local enhancements of CH4 and CO are estimated using measurements from 14 air quality sites in the SFBA combined together with global background measurements. Mean annual CH4 emissions are estimated from the product of Bay Area Air Quality Management District (BAAQMD) emission inventory CO and the slope of ambient local CH4 to CO. The resulting top-down estimates of CH4 emissions are found to decrease slightly from 1990 to 2012, with a mean value of 240 ± 60 GgCH4 yr⁻¹ (at 95% confidence) in the most recent (2009–2012) period, and correspond to reasonably a constant factor of 1.5–2.0 (at 95% confidence) times larger than the BAAQMD CH4 emission inventory. However, we note that uncertainty in these emission estimates is dominated by the variation in CH4:CO enhancement ratios across the observing sites and we expect the estimates could represent a lower-limit on CH4 emissions because BAAQMD monitoring sites focus on urban air quality and may be biased toward CO rather than CH4 sources.},
doi = {10.1016/j.atmosenv.2015.01.065},
url = {https://www.osti.gov/biblio/2325268}, journal = {Atmospheric Environment (1994)},
issn = {1352-2310},
number = C,
volume = 107,
place = {United Kingdom},
year = {Wed Apr 01 00:00:00 EDT 2015},
month = {Wed Apr 01 00:00:00 EDT 2015}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at https://doi.org/10.1016/j.atmosenv.2015.01.065

Citation Metrics:
Cited by: 11 works
Citation information provided by
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Works referenced in this record:

Methane emissions inventory verification in southern California
journal, January 2010


Anthropogenic emissions of methane in the United States
journal, November 2013


A multitower measurement network estimate of California's methane emissions: CALIFORNIA'S METHANE EMISSIONS
journal, October 2013


Methane Leaks from North American Natural Gas Systems
journal, February 2014


Quantifying sources of methane using light alkanes in the Los Angeles basin, California: SOURCES OF METHANE IN L.A.
journal, May 2013


On the Sources of Methane to the Los Angeles Atmosphere
journal, August 2012