Missing wintertime methane emissions from New York City related to combustion

作者：Luke D. Schiferl, Andrew Hallward-Driemeier, Yuwei Zhao, Ricardo Toledo‐Crow, R. Commane · 发表于：Atmospheric chemistry and physics · 年份：2025 · DOI：10.5194/acp-25-15683-2025 · 被引用次数：2 · 研究领域：Atmospheric and Environmental Gas Dynamics、Spectroscopy and Laser Applications、Atmospheric chemistry and aerosols

Abstract. Accurately quantifying methane emissions from cities, and understanding the processes that drive these emissions, is important for reaching climate mitigation goals. Methane emissions from New York City metropolitan area (NYCMA), the most populous urban area of the United States, have consistently been underestimated by emission inventories compared to aircraft and satellite observations. In this study, we used continuous rooftop measurements of methane over six winter-to-spring transitions (January–May 2019–2024) to examine the variability of city-scale methane enhancements (ΔCH4) and estimate methane emissions from the NYCMA. We found large variability in the 10 d mean observed ΔCH4 (∼50–250 ppbv) and monthly afternoon methane emissions rates (10.1–30.4 kg s−1) within and between the years of our study period. A recently released high-resolution regional methane emission inventory developed for the NYCMA performed better than other global and national inventories against the rooftop observations but still underestimated methane emissions, especially in winter. The estimates of methane emissions correlated with those of carbon monoxide (CO) emissions, determined from coincident measurements, suggesting a common city-scale incomplete combustion source for both methane and CO. Our analysis of these continuous measurements also implies a consistent diurnal cycle in urban methane emissions from the NYCMA, which reveals a potential bias in traditional afternoon-only app...