Abstract:

[Objective] Airport emergency events can significantly disturb normal flight operations and lead to temporary flight control measures, which may further affect aircraft pollutant emissions and the surrounding air quality of airports. As an important source of air pollutants during airport operations, aircraft emissions are closely associated with flight activity levels, operational procedures, and aircraft movement characteristics. Under normal operating conditions, aircraft emission characteristics are relatively stable; however, emergency events may cause temporary changes in aircraft operation patterns, resulting in variations in pollutant emission levels and spatial distribution characteristics. With the continuous growth of air transportation activities, aircraft emissions during airport operations have attracted increasing attention due to their potential influence on local atmospheric environments. Therefore, evaluating emission changes under emergency scenarios is necessary for improving the understanding of airport environmental impacts.

Although aircraft emission inventories have been widely applied to evaluate the environmental impacts of airport operations, most studies focus on normal operational scenarios, while the emission characteristics under temporary flight control conditions remain insufficiently investigated. In particular, the influence of temporary flight control on aircraft pollutant emission levels and spatial distribution characteristics before, during, and after emergency events requires further analysis. Therefore, this study investigates the influence of temporary flight control caused by airport emergency events on aircraft pollutant emissions. The changes in total emissions and temporal-spatial distribution characteristics of aircraft pollutants during different operational periods are analyzed to provide a basis for airport environmental impact assessment and emergency management. [Methods] Tianjin Binhai International Airport was selected as the study area. Based on actual flight trajectory data, a hybrid machine learning model was applied to characterize aircraft fuel consumption during take-off and landing operations. The model was used to establish the relationship between flight trajectory characteristics and fuel flow, providing the basis for estimating aircraft fuel consumption under actual operating conditions. The estimated fuel consumption was combined with the standard emission database provided by the International Civil Aviation Organization (ICAO) to calculate aircraft pollutant emissions. A high-resolution dynamic emission inventory was constructed for the temporary flight control period and the periods before and after the emergency event. The study period was divided into three stages: the period before the event (C1), the temporary flight control period (C2), and the period after the event (C3). The emission characteristics of aircraft pollutants during different periods were compared to evaluate the influence of temporary flight control. Based on the constructed dynamic emission inventory, the temporal-spatial distribution characteristics of major aircraft pollutants were analyzed. The horizontal distribution characteristics were evaluated according to different airport functional areas, including runway areas, taxiways, and aprons. The vertical distribution characteristics were analyzed according to different altitude ranges, including the middle and high altitude region above 500 m and the near-ground region from 0 to 500 m. The constructed emission inventory provides a detailed description of aircraft pollutant emissions under different operational conditions and allows comparison of emission variations among different stages of emergency events. This approach enables the identification of emission changes caused by temporary flight control and supports quantitative evaluation of airport emergency impacts. [Results] The results show that temporary flight control significantly affected aircraft pollutant emissions in the airport area. During the temporary flight control period (C2), the daily average emissions of major aircraft pollutants decreased by 23.1% and 27.4% compared with the period before the event (C1) and the period after the event (C3), respectively. The reduction in total emissions was mainly related to the decrease in aircraft operating activities caused by temporary flight control. In addition to changes in total emission levels, temporary flight control also significantly changed the temporal-spatial distribution characteristics of aircraft pollutants. From the perspective of horizontal distribution, pollutant emissions decreased in runway areas but increased in taxiway and apron areas during C2. The daily average NOx emission in runway areas was 22.9 g·d⁻¹, which decreased by 20.2% compared with C1. In contrast, the daily average emissions of CO and HC in taxiway and apron areas were 11.24 g·d⁻¹ and 0.87 g·d⁻¹, respectively, representing increases of 21.7% and 18.1% compared with C1. The changes in different airport functional areas were mainly associated with variations in aircraft operation processes during temporary flight control. The reduction of flight activities resulted in decreased emissions in areas related to aircraft take-off and landing operations, while changes in ground operation conditions contributed to increased emissions in taxiway and apron areas. The vertical distribution characteristics of pollutant emissions also changed significantly during the temporary flight control period. The daily average emissions of pollutants increased in the middle and high altitude region above 500 m but decreased in the near-ground region from 0 to 500 m. Compared with C1, the proportion of NO_x emissions in the middle and high altitude region increased by 20.2% during C2. Meanwhile, the proportions of HC and CO emissions in the near-ground region decreased by 27.2% and 28.3%, respectively. These results indicate that temporary flight control not only affects the total amount of aircraft pollutant emissions but also changes the spatial distribution characteristics of pollutants at different airport areas and altitude levels. [Conclusion] The results demonstrate that airport emergency events have significant impacts on aircraft pollutant emissions and their spatial distribution characteristics. Temporary flight control caused by emergency events changes aircraft operating conditions, resulting in variations in both total pollutant emissions and their distribution patterns in horizontal and vertical dimensions. The assessment of aircraft pollutant emissions under emergency scenarios should consider the changes caused by temporary flight control. Systematic analysis of the influence of temporary flight control on aircraft operating pollutant emissions can provide support for airport emergency response and effective emission control. The dynamic emission assessment method applied in this study can provide a reference for evaluating the environmental impacts of airport emergency events. The findings also emphasize the necessity of incorporating temporary operational changes into airport emission assessments.

Key words: airport emissions, machine learning, high-precision emission inventory, horizontal distribution characteristics, vertical distribution characteristics

摘要：

【目的】针对机场突发事件导致航班临时管制后飞机污染物排放变化规律及影响效应尚不明确的问题，研究航班临时管制对飞机污染物排放总量及其时空分布特征的影响，为机场突发事件环境影响评估与应急管理提供依据。【方法】以天津滨海国际机场为例，基于真实飞行航迹，采用混合机器学习模型，结合国际民航组织（International Civil Aviation Organization，ICAO）标准排放数据库，构建航班临时管制时段及前后飞机起降阶段高精度动态排放清单，分析污染物排放时空分布特征。【结果】航班临时管制时段（C2）机场区域飞机主要污染物排放日均值较事件发生前期（C1）和后期（C3）分别降低23.1%和27.4%。受航班临时管制影响，污染物排放时空特征发生显著变化。水平分布显示，C2时段污染物排放在跑道区域降低，在滑行道和停机坪区域升高。其中，NO_x跑道区域排放量日均值为22.9 g·d⁻¹，较C1下降20.2%；CO和HC在滑行道、停机坪区域排放量日均值分别为11.24 g·d⁻¹和0.87 g·d⁻¹，较C1分别增加21.7%和18.1%。垂直分布显示，C2时段污染物日均排放量在500 m以上中高空区域增加，在0－500 m近地面区域降低；相较于C1，NO_x中高空区域排放占比增加20.2%，HC和CO近地面区域排放占比分别降低27.2%和28.3%。【结论】突发事件对机场及周边污染物排放影响显著。分析航班临时管制对飞机运行污染物排放的影响效应，可为机场科学应对突发情况、有效管控提供支撑。

关键词: 机场排放, 机器学习, 高精度排放清单, 水平分布特征, 垂直分布特征