Researchers report a framework for monitoring greenhouse gas (GHG) emissions in urban regions. Assessing the efficacy of efforts to reduce urban GHG emissions in the United States requires methods to track and verify reported emissions over time. Maryann Sargent and colleagues developed a top-down approach to assess CO2 emissions and used the approach to quantify CO2 emissions in the Boston urban region from September 2013 to December 2014. Concentrations of CO2 were measured continuously at two sites in the urban core at different altitudes and at three sites located more than 90 km from the city center. The authors modeled regional emissions by combining these measurements with a particle dispersion model, a high-resolution bottom-up emissions inventory, and a model of plant photosynthesis and respiration. The authors determined the model uncertainty to be 18%, which implies that the method is capable of detecting changes in emissions greater than 18%. Photosynthetic CO2 uptake by urban vegetation during the afternoon largely offsets anthropogenic CO2 emissions between May and September. Reducing the spatial resolution of the bottom-up emissions inventory led to underestimation of emissions by 15-30%. According to the authors, the framework could be used to assess the efficacy of GHG reduction efforts in cities around the world.
Article #18-03715: "Anthropogenic and biogenic CO2 fluxes in the Boston urban region," by Maryann Sargent et al.
MEDIA CONTACT: Maryann Sargent, Harvard University, Cambridge, MA; tel: 508-277-4778; e-mail: <mracine@fas.harvard.edu>
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