Abstract：
As part of its commitment to the United Nations Framework Convention on Climate Change, the U.S. annually develops a national estimate of methane emissions from municipal solid waste (MSW) landfills by aggregating activity data from each facility. Since 2010, the U.S. has reported a 20 % decrease in MSW landfill emissions despite a 21 % increase in tons disposed. Operator-submitted data were investigated to understand the causes of this decline. In the U.S., operators of landfills with a gas collection and control system (GCCS) calculate their facility\'s emissions via two separate approaches - (1) first-order decay (FOD) and (2) collection efficiency assumption (CEA) - and select either result to feed into the annual inventory. The FOD model predicts methane generation proportional to waste disposal and that approach calculated a 19 % increase in total methane generated from 2010 to 2022, whereas generation via the CEA approach decreased by 8.9 %. The amount of measured methane collected has increased 7.5 % for the same years. Discrepancies between the two models\' generated methane, assumed gas collection efficiencies, and oxidized methane compound into substantive differences in national estimates. Operators more frequently select the CEA method, which results in decreased national estimates. If only the FOD method was used, U.S. MSW landfill emissions would be 1.3-1.7 times greater than current estimates which is similar to recent extrapolations from remote sensing campaigns in the U.S. Both models contain parameters with large inherent uncertainty. Without measurement methods that continuously quantify both point-source and diffuse emissions, an assessment of either equation\'s accuracy cannot be made.
摘要：
作为其对《联合国气候变化框架公约》承诺的一部分，美国每年通过汇总每个设施的活动数据，对城市固体废物（MSW）垃圾填埋场的甲烷排放量进行国家估算。自2010年以来，尽管处理吨增加了21％，但美国的垃圾填埋场排放量却减少了20％。对运营商提交的数据进行了调查，以了解这种下降的原因。在美国,具有气体收集和控制系统（GCCS）的垃圾填埋场的运营商通过两种单独的方法计算其设施的排放量-（1）一阶衰减（FOD）和（2）收集效率假设（CEA）-并选择任一结果输入年度清单。FOD模型预测甲烷的产生与废物处置成比例，该方法计算出从2010年到2022年产生的总甲烷增加了19％，而通过CEA方法产生的甲烷减少了8.9％。在同一年，测得的甲烷收集量增加了7.5％。两个模型产生的甲烷之间的差异，假定的气体收集效率，和氧化甲烷化合物在国家估计中的实质性差异。操作员更频繁地选择CEA方法，这导致国家估计数下降。如果仅使用FOD方法，美国MSW垃圾填埋场的排放量将比目前的估计值高1.3-1.7倍，这与美国遥感运动的最新推断相似。两种模型都包含具有较大固有不确定性的参数。没有连续量化点源和扩散排放的测量方法，不能对任何一个方程的准确性进行评估。
