Mayhew Alfred W, Haskins Jessica D
Department of Atmospheric Sciences, University of Utah, Salt Lake City, Utah 84112, United States.
Environ Sci Technol. 2025 Jan 14;59(1):679-688. doi: 10.1021/acs.est.4c11697. Epub 2025 Jan 3.
Methane (CH) is a greenhouse gas with a global warming potential 81.2 times higher than carbon dioxide (CO). The intentional emission of oxidants into the atmosphere has been proposed as a geoengineering solution to accelerate the oxidation of CH to CO, thereby reducing surface warming. However, there has been little consideration for competing atmospheric oxidation pathways that will reduce CH oxidation efficiencies and result in the formation of secondary pollutants such as ozone and particulate matter. Using a global chemical-transport model, we simulate a proposed technology to intentionally emit HO into the atmosphere to elevate OH concentrations and enhance CH oxidation. We find that proposed emission rates of oxidants have minimal impacts on monthly average tropospheric ozone and particulate matter concentrations. However, competition for the oxidation of CH would necessitate widespread adoption of such technology to remove substantial concentrations of atmospheric CH, which would in-turn cause considerable increases in regional winter-time particulate matter. Our work underscores the need to consider competing chemistry in evaluating the efficacy and side effects of proposals to enhance the atmospheric oxidation of CH as a climate solution.
甲烷（CH₄）是一种温室气体，其全球变暖潜能是二氧化碳（CO₂）的81.2倍。向大气中有意排放氧化剂已被提议作为一种地球工程解决方案，以加速将CH₄氧化为CO₂，从而减少地表变暖。然而，对于会降低CH₄氧化效率并导致形成臭氧和颗粒物等二次污染物的竞争性大气氧化途径，人们几乎没有考虑过。我们使用全球化学传输模型，模拟了一项提议的技术，即向大气中有意排放HOₓ以提高OH浓度并增强CH₄氧化。我们发现，提议的氧化剂排放速率对对流层臭氧和颗粒物的月平均浓度影响极小。然而，由于存在对CH₄氧化的竞争，要去除大量大气中的CH₄就需要广泛采用这种技术，而这反过来会导致区域冬季颗粒物大幅增加。我们的工作强调，在评估将增强大气中CH₄氧化作为一种气候解决方案的提议的有效性和副作用时，需要考虑竞争性化学反应。
