Zhou Luxi, Baker Kirk R, Napelenok Sergey L, Pouliot George, Elleman Robert, O'Neill Susan M, Urbanski Shawn P, Wong David C
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States; National Academies of Science, Engineering and Medicine, Washington, DC 20001, United States.
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States.
Sci Total Environ. 2018 Jun 15;627:523-533. doi: 10.1016/j.scitotenv.2018.01.237. Epub 2018 Feb 3.
Crop residue burning is a common land management practice that results in emissions of a variety of pollutants with negative health impacts. Modeling systems are used to estimate air quality impacts of crop residue burning to support retrospective regulatory assessments and also for forecasting purposes. Ground and airborne measurements from a recent field experiment in the Pacific Northwest focused on cropland residue burning was used to evaluate model performance in capturing surface and aloft impacts from the burning events. The Community Multiscale Air Quality (CMAQ) model was used to simulate multiple crop residue burns with 2 km grid spacing using field-specific information and also more general assumptions traditionally used to support National Emission Inventory based assessments. Field study specific information, which includes area burned, fuel consumption, and combustion completeness, resulted in increased biomass consumption by 123 tons (60% increase) on average compared to consumption estimated with default methods in the National Emission Inventory (NEI) process. Buoyancy heat flux, a key parameter for model predicted fire plume rise, estimated from fuel loading obtained from field measurements can be 30% to 200% more than when estimated using default field information. The increased buoyancy heat flux resulted in higher plume rise by 30% to 80%. This evaluation indicates that the regulatory air quality modeling system can replicate intensity and transport (horizontal and vertical) features for crop residue burning in this region when region-specific information is used to inform emissions and plume rise calculations. Further, previous vertical emissions allocation treatment of putting all cropland residue burning in the surface layer does not compare well with measured plume structure and these types of burns should be modeled more similarly to prescribed fires such that plume rise is based on an estimate of buoyancy.
焚烧作物秸秆是一种常见的土地管理做法，会导致多种污染物排放，对健康产生负面影响。建模系统用于估算焚烧作物秸秆对空气质量的影响，以支持回顾性监管评估以及用于预测目的。在太平洋西北部最近一项针对农田秸秆焚烧的实地试验中进行的地面和空中测量，被用于评估模型在捕捉焚烧事件对地表和高空影响方面的性能。社区多尺度空气质量（CMAQ）模型被用于使用特定场地信息以及传统上用于支持基于国家排放清单评估的更一般假设，以2公里的网格间距模拟多次作物秸秆焚烧。特定场地研究信息，包括燃烧面积、燃料消耗和燃烧完整性，与国家排放清单（NEI）过程中使用默认方法估算的消耗量相比，平均导致生物质消耗量增加了123吨（增加了60%）。根据实地测量获得的燃料负荷估算的浮力热通量，这是模型预测火羽上升的关键参数，比使用默认场地信息估算时高出30%至200%。浮力热通量的增加导致羽流上升高度提高了30%至80%。该评估表明，当使用特定区域信息来指导排放和羽流上升计算时，监管空气质量建模系统可以复制该地区作物秸秆焚烧的强度和传输（水平和垂直）特征。此外，之前将所有农田秸秆焚烧都置于表层的垂直排放分配处理方法与实测羽流结构相比效果不佳，这类焚烧的建模应更类似于规定火烧，使羽流上升基于浮力估算。
