中国农业机械的使用特征及其尾气排放的时空分布

Spatiotemporal distribution of activity and its emissions for agricultural equipment in China

我国农业机械保有量巨大且其尾气排放不容忽视.了解其使用特征、分析其尾气排放的时空分布,对提高非道路机械尾气排放清单准确性、制定减排政策具有重要意义.本研究通过实际调研获取我国农业机械的活动水平,并在此基础上分析其活动水平与机械类型、车龄、分布地区之间的关系,以此量化其使用特征;使用BP神经网络的方法预测我国2020—2025年农业机械保有量,结合调研的活动水平和收集的排放因子数据,估算我国2020—2025年农业机械尾气污染物排放清单;基于各省份农业机械保有量、活动水平的差异,探讨我国农业机械尾气排放的空间分布.研究结果表明:(1)我国农业机械的使用因机械类型、车龄、分布地区等因素的影响存在较大的变化性.农业机械的年均工作时间可在217~1721 h·a^(-1)之间变化,单台机械年均耗油量可在0.2~10.5 t·a^(-1)之间变化.(2)据本研究预测,2020年后,我国农业机械保有量将持续增长,受排放标准提升、老旧机械淘汰等减排措施的影响,其尾气排放呈下降趋势,到2025年,农业机械CO、HC、NO_(x)和PM_(2.5)排放将比2020年下降0.1%~26.2%.(3)与地区的农业机械保有量密切相关,河南、山东、安徽的农业机械尾气排放量最大.与春季相比,秋季各省份农业机械尾气排放更为显著.

Emissions from agricultural equipment cannot be neglected due to its large population in China.It is of great significance to characterize the spatiotemporal distribution of activity and its emissions for agricultural equipment in order to improve the accuracy of emission inventory development for non-road equipment for emissions reduction policies-making,which has served as the key objective of this study.Activity data for in-use agricultural equipment were collected and analyzed via multiple surveillance approaches.A back-propagation neural network method was used to predict the population of agricultural equipment from 2020 to 2025.The emission inventory for agricultural equipment of China from 2020 to 2025 was estimated using activity and emission factors data collected in this study.Furthermore,the emissions from agricultural equipment in different provinces in a typical month were estimated and used as surrogates to characterize its spatial distribution.The results showed that:(1)There exists a large variation in activity data for agricultural equipment due to a variety of factors such as equipment type,age,and geographic areas.The average usage of agricultural equipment can vary from 217 to 1721 hours per year.The average fuel consumption of a single equipment can vary from 0.2 to 10.5 tons per year.(2)It was predicted that the population of agricultural equipment in China will continue to grow after 2020,and its emissions will show a downward trend resulting from stringent emission standards and scrappage of old equipment.By 2025,CO,HC,NO_(x) and PM_(2.5) emissions from agricultural equipment will decrease by 0.1% to 26.2% compared to those in 2020.(3)Henan,Shandong and Anhui Provinces are the top three provinces with emissions from agricultural equipment.In general,emissions from agricultural equipment were higher in Autumn than those in Spring.