Underestimation of Thermogenic Methane Emissions in New York City (New York City methane emissions: what are we missing?)

Published

May 14, 2024

Author(s)

Joseph R. Pitt, Israel Lopez Coto, Anna Karion, Kristian D. Hajny, Jay M. Tomlin, Robert Kaeser, Thilina Jayarathne, Brian H. Stirm, Cody R. Floerchinger, Christopher P. Loughner, Róisín Commane, Conor K. Gately, Lucy R. Hutyra, Kevin R. Gurney, Geoffrey S. Roest, Jianming Liang, Sharon Gourdji, Kimberly Mueller, James Whetstone, Paul B. Shepson

Abstract

Recent studies have shown that methane emissions are underestimated by inventories in many US urban areas. This has important implications for climate change mitigation policy at the city, state, and national levels. Uncertainty in both the spatial distribution and sectoral allocation of urban emissions can limit the ability of policy makers to develop appropriately focused emission reduction strategies. Top-down emission estimates based on atmospheric greenhouse gas measurements can help to improve inventories and inform policy decisions. This study presents a new high-resolution (0.02 × 0.02°) methane emission inventory for New York City and its surrounding area, constructed using the latest activity data, emission factors, and spatial proxies. The new high-resolution inventory estimates of methane emissions for the New York-Newark urban area are 1.3 times larger than those for the gridded Environmental Protection Agency inventory. We used aircraft mole fraction measurements from nine research flights to optimize the high-resolution inventory emissions within a Bayesian inversion. These sectorally optimized emissions show that the high-resolution inventory still significantly underestimates methane emissions within the New York-Newark urban area, primarily because it underestimates emissions from thermogenic sources (by a factor of 2.3). This suggests that there remains a gap in our process-based understanding of urban methane emissions.

Citation

Environmental Science and Technology

Pub Type

Journals

Download Paper

https://doi.org/10.1021/acs.est.3c10307

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Keywords

urban emissions, greenhouse gas emissions, methane, airborne greenhouse gas measurements, Bayesian inverse modelling, emissions inventory development, New York City

Citation

Pitt, J. , Lopez Coto, I. , Karion, A. , Hajny, K. , Tomlin, J. , Kaeser, R. , Jayarathne, T. , Stirm, B. , Floerchinger, C. , Loughner, C. , Commane, R. , Gately, C. , Hutyra, L. , Gurney, K. , Roest, G. , Liang, J. , Gourdji, S. , Mueller, K. , Whetstone, J. and Shepson, P. (2024), Underestimation of Thermogenic Methane Emissions in New York City (New York City methane emissions: what are we missing?), Environmental Science and Technology, [online], https://doi.org/10.1021/acs.est.3c10307, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936542 (Accessed November 21, 2024)