Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21205, United States.
NOAA Global Monitoring Laboratory, Boulder, Colorado 80305, United States.
Environ Sci Technol. 2024 Sep 3;58(35):15539-15550. doi: 10.1021/acs.est.4c00380. Epub 2024 Aug 21.
Oil and natural gas (O&G) production and processing activities have changed markedly across the U.S. over the past several years. However, the impacts of these changes on air pollution and greenhouse gas emissions are not clear. In this study, we examine U.S. ethane (CH) emissions, which are primarily from O&G activities, during years 2015-2020. We use CH observations made by the NOAA Global Monitoring Laboratory and partner organizations from towers and aircraft and estimate emissions from these observations by using an inverse model. We find that U.S. CH emissions (4.43 ± 0.2 Tg·yr) are approximately three times those estimated by the EPA's 2017 National Emissions Inventory (NEI) platform (1.54 Tg·yr) and exhibit a very different seasonal cycle. We also find that changes in U.S. CH emissions are decoupled from reported changes in production; emissions increased 6.3 ± 7.6% (0.25 ± 0.31 Tg) between 2015 and 2020 while reported CH production increased by a much larger amount (78%). Our results also suggest an apparent correlation between CH emissions and CH spot prices, where prices could be a proxy for pressure on the infrastructure across the supply chain. Overall, these results provide insight into how U.S. CH emissions are changing over time.
过去几年，美国的石油和天然气（O&G）生产和加工活动发生了显著变化。然而，这些变化对空气污染和温室气体排放的影响尚不清楚。在本研究中，我们研究了 2015-2020 年期间美国乙烷（CH）排放情况，这些排放主要来自 O&G 活动。我们利用来自塔和飞机的 NOAA 全球监测实验室和合作伙伴组织的 CH 观测值，并使用反演模型估算这些观测值的排放量。我们发现，美国 CH 排放量（4.43±0.2Tg·yr）约为美国环保署 2017 年国家排放清单（NEI）平台估计值（1.54Tg·yr）的三倍，且具有非常不同的季节性周期。我们还发现，美国 CH 排放量的变化与报告的产量变化脱钩；2015 年至 2020 年间，排放量增加了 6.3±7.6%（0.25±0.31Tg），而报告的 CH 产量增加了更多（78%）。我们的研究结果还表明，CH 排放量与 CH 现货价格之间存在明显的相关性，价格可能是供应链中基础设施压力的一个指标。总的来说，这些结果提供了有关美国 CH 排放量随时间变化的见解。
