The Impact of COVID‐19 on CO₂ Emissions in the Los Angeles and Washington DC/Baltimore Metropolitan Areas

Abstract

Responses to public health threats presented by the global COVID-19 pandemic dramatically altered daily activities in cities around the world, including in the Los Angeles and Washington DC/Baltimore metropolitan areas. Researchers have attempted to determine the extent to which CO 2 emissions were impacted by the pandemic, linking changes in emissions to processes and sectors using different types of activity data and baselines for comparisons (Le Quéré et al., 2020;Liu et al., 2020;Zheng et al., 2020). One study shows that CO 2 emissions declined by 3.9% globally in the first 4 months in 2020, attributing half of this decline to changes in traffic and mobility (Le Quéré et al., 2020). Unlike these studies, which use only activity data to estimate declines, here we also use atmospheric CO 2 observations to detect when and how emissions were impacted, and focus on CO 2 emissions reductions at the city scale.Our analysis relies on high-accuracy atmospheric CO 2 observations from urban networks, building on a recently published study that used lower-accuracy CO 2 sensors to estimate COVID-19 related impacts for the San Francisco Bay area (Turner et al., 2020). Here, we evaluate impacts in two separate metropolitan areas: Los Angeles and Washington DC/Baltimore, allowing for an inter-comparison between two large urban regions. In Los Angeles and Washington DC/Baltimore, traffic congestion and commuting play dominant

A multi-city urban atmospheric greenhouse gas measurement data synthesis

“…The CO 2 Urban Synthesis and Analysis (CO 2 -USA) network is a synthesis effort primarily supported by the U.S. National Oceanic and Atmospheric Administration, with additional support from National Institute of Standards and Technology. CO 2 -USA was established to build a collaborative network of urban carbon cycle researchers to facilitate data sharing, create analysis frameworks to enable cross-city synthesis analyses 19 , and enable new collaborations tackling objectives that are difficult to address in isolation (Fig. 1 ).…”

“…Building a multi-city analysis framework will enable studies to quantify and understand similarities and differences in how much, where, and why GHG fluxes differ across cities. Applications could include assessing changes in emissions during the COVID-19 pandemic or creating consistent methodologies to assess emissions across different cities that are pursuing emission reduction policies 19 . This information could then be presented to urban stakeholders and policymakers to evaluate progress towards emission reduction goals (Fig.…”

Dramatic Lockdown Fossil Fuel CO2 Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations

“… 2 , 3 Atmospheric observations of CO 2ff during COVID-19 lockdowns have not yet been reported, and only a small number of studies have detected changes from atmospheric observations of total CO 2 . 9 − 12 …”

The impact of the COVID-19 lockdown on greenhouse gases: a multi-city analysis of in situ atmospheric observations

“…Such networks have been deployed for several years at several cities across the globe, have nearreal-time dedicated high-precision, high-accuracy measurements of CO 2 , carbon monoxide (CO), and methane (CH 4 ) [9][10][11][12][13][14][15]. These networks have been used to infer [16] or quantify [17] changes in emissions over time, and with atmospheric inverse systems for the quantification of urban emissions [12], [18][19][20]. Recently, this technique was used to quantify the relative reduction of CO 2 emissions from activities associated with COVID-19 in Los Angeles and D.C./Baltimore, [20] and San Francisco [21].…”

“…These networks have been used to infer [16] or quantify [17] changes in emissions over time, and with atmospheric inverse systems for the quantification of urban emissions [12], [18][19][20]. Recently, this technique was used to quantify the relative reduction of CO 2 emissions from activities associated with COVID-19 in Los Angeles and D.C./Baltimore, [20] and San Francisco [21]. Both studies found emissions reductions on the order of 30%.…”