Development of database of real-world diesel vehicle emission factors for China

A database of real-world diesel vehicle emission factors, based on type and technology, has been developed following tests on more than 300 diesel vehicles in China using a portable emission measurement system. The database provides better understanding of diesel vehicle emissions under actual driving conditions. We found that although new regulations have reduced real-world emission levels of diesel trucks and buses significantly for most pollutants in China,NO_x emissions have been inadequately controlled by the current standards, especially for diesel buses, because of bad driving conditions in the real world. We also compared the emission factors in the database with those calculated by emission factor models and used in inventory studies. The emission factors derived from COPERT (Computer Programmer to calculate Emissions from Road Transport) and MOBILE may both underestimate real emission factors, whereas the updated COPERT and PART5 (Highway Vehicle Particulate Emission Modeling Software) models may overestimate emission factors in China. Real-world measurement results and emission factors used in recent emission inventory studies are inconsistent, which has led to inaccurate estimates of emissions from diesel trucks and buses over recent years. This suggests that emission factors derived from European or US-basedmodels will not truly represent real-world emissions in China. Therefore, it is useful and necessary to conduct systematic real-world measurements of vehicle emissions in China in order to obtain the optimum inputs for emission inventory models.     

不同破损程度下军用车辆镀锌钢板腐蚀行为研究

目的研究军用车辆不同破损程度下的镀锌板腐蚀行为。方法以3.5%Na Cl溶液为实验介质,利用开路电位、电化学阻抗谱及动电位极化曲线技术进行研究。结果镀锌钢板的开路电位比基板低约0.3 V,镀层腐蚀速度随着破损率的增加逐渐增大,基板的腐蚀速度最低。结论镀锌层的腐蚀对破损试样基体起重要的保护作用。     

机动车尾气污染与防治措施研究

改善空气质量,减少机动车尾气对雾霾的贡献已是当务之急.防治机动车尾气污染,关键是国家应制定和完善相应的法律、法规、规章和标准,出台鼓励新能源机动车的研发、生产、销售的优惠政策.环保部门要把住机动车环保检测第一关,严格机动车环保绿色标志的发放,会同工商部门对油品实行日常监管,加强环保宣传、提高人们的环保意识.公安、环保联动执法,杜绝超标车上路,淘汰黄标车.政府相关部门要科学规划和绿化城市道路.     

基于无人机探空和数值模拟天津一次重污染过程分析

污染发生在边界层中,边界层热力和动力垂直结构对重污染天气形成有显著影响.本文基于无人机探空、地基遥感观测和数值模式,开展天津地区2019年1月10~15日重污染过程期间边界层垂直结构及污染成因分析,以期加强北方沿海城市边界层过程对重污染影响规律认知,提升重污染天气预报预警准确率.结果表明：大气温度层结对重污染天气形成、持续和消散有显著影响,此次过程伴随逆温层的发展和消散,PM_2.5高浓度区白天向大气上层发展,高度可达300 m以上,夜间向近地面压缩,高度在100 m左右;雾天气出现并在白天维持,改变了边界层垂直结构特征,雾顶逆温的持续存在抑制了污染物向大气上层扩散,使得白天湍流垂直混合过程贡献明显下降,导致近地面重污染天气维持和发展;过程期间区域输送贡献率为66.6%,边界层垂直结构与重污染天气区域输送密切相关,区域污染物输送高度主要出现在边界层顶部以及雾顶逆温层以上的大风速层处,且随着边界层和雾顶抬升高度的变化,通过下沉运动影响地面,形成北部弱高压天气控制下静稳天气区域输送;边界层垂直结构影响冷空气对空气质量的改善效果,S3阶段雾顶的强逆温导致冷空气无法通过湍流切应力传导到地面,在高低空存在明显的风速差,冷空气影响地面时间延后,作用减弱,重污染天气无法彻底缓解.     

航空相机载荷舱热环境分析

目的详细分析航空相机主体热设计的关键边界条件--航空相机载荷舱的热环境。方法通过载荷舱的热平衡方程,分析影响载荷舱热环境的主要因素,系统地总结适用于工程应用的分析方法。结果对于辐射热环境需考虑大气透明度、地面状况等因素,对流热环境可采用Hilbert提出的经验表达式计算载荷舱背风面的对流换热系数,气动热环境采用Eckert参考焓法估算载荷舱的气动热是合适的,且宜采用电热防冰系统及热空气加热防结露系统。结论该研究结果是航空相机主体热设计的基础,适用于对各类航空相机载荷舱热环境分析和环境控制系统设计。     

应用受体模型(CMB)对北京市大气PM_(2.5)来源的解析研究

为研究影响北京市大气环境PM2.5污染水平的主要来源,于2012年8月—2013年7月,依托北京市大气地面观测网络在10个监测点采集的491 d(次)大气PM2.5有效样本,对其化学组分进行了测试分析;从城市大气污染源组成出发,建立和完善了5类固定点源、2类流动源、4类无组织面源的PM2.5排放成分谱.应用受体模型(CMB)开展了来源解析研究.结果显示:1观测期间大气环境PM2.5的来源主要包括:一次来源机动车(16%)、燃煤(15%)、土壤尘(6%)、二次硫酸铵和硝酸铵(36%),以及有机物(20%)和其他未识别来源(7%);与历史解析结果相比,燃煤源分担率有所下降,二次无机盐与有机物分担率上升,且二次硝酸盐有赶超二次硫酸盐之势;2从主要组分的来源看,观测期间环境大气PM2.5中近25%的硫酸盐来自于燃煤锅炉和电厂排放,17%的有机物来自机动车排放;3北京市PM2.5来源类型大致相同,但各点位PM2.5来源种类和分担率具有一定差异,对一些排放量较大的局地排放源有比较明确的响应.研究表明,开展区域性PM2.5治理、大力削减前体物、严格控制本地机动车、燃煤等PM2.5排放都是改善北京市空气质量的重要途径.     

汽车内饰材料老化试验研究

本文介绍了汽车内饰材料常见的老化试验方法:人工加速老化试验、IP/DP箱暴晒和整车暴晒,分别讨论三种试验方法涉及的规范以及操作性.人工加速老化试验能快速掌握汽车内饰材料老化性能,缩短材料研发周期;IP/DP箱和整车对内饰件或其装配件进行的老化试验降低内饰材料加工工艺存在的风险,确保了内饰材料质量.整车暴晒收集的数据为人...     

汽车尾气净化减排技术进展

评述了国内外汽车尾气净化减排技术的新进展及应用情况。     

天津市机动车尾气排放因子研究

通过调查研究天津市机动车车型构成、保有量、车辆行驶状况、气象数据和油品等基础数据,利用COPERT IV模型计算了在国1、国2、国3、国4和国5排放标准下机动车尾气中CO、NO_x、VOC和PM_(2.5)的排放因子.应用车载测试系统在实际道路上对国4柴油货车的排放因子进行了测量,并将模型结果与实测结果进行了比较,研究表明,国4排放标准下,污染物排放实测数据普遍高于模型模拟数据.对于轻型载货柴油车而言,实际道路测量的CO、NO_x、VOC和PM_(2.5)的排放因子分别是模型模拟数据的2.5、4.3、1.9和1.2倍;对于中型载货柴油车而言,以上污染物的实测排放因子分别是模型的1.3、2.1、1.0和1.2倍;对于重型载货柴油车而言,以上污染物的实测排放因子分别是模型的1.7、1.9、1.1和1.2倍.     

Bioenergy recovery from landfill gas: A case study in China

Landfill gas (LFG) utilization which means a synergy between environmental protection and bioenergy recovery was investigated in this study. Pressure swing adsorption technology was used in LFG purification, and laboratory experiment, pilot-scale test, and on-site demonstration were carried out in Shenzhen, China. In the laboratory experiment, A-type carbon molecular sieve was selected as the adsorbent by comparison of several other adsorbents. The optimal adsorption pressure and adsorption time were 0.25 MPa and 2 min, respectively, under which the product generation rate was 4.5 m³/h and the methane concentration was above 90%. The process and optimization of the pilot-scale test were also reported in the paper. The product gas was of high quality compared with the National Standard of Compressed Natural Gas as Vehicle Fuel (GB18047-2000), when the air concentration in feed gas was under 10.96%. The demonstration project was composed of a collection system, production system, and utilization system. The drive performance, environmental protection performance, and economic feasibility of the product gas — as alternative fuel in passenger car, truck, and bulldozer—were tested, showing the feasibility technology for LFG utilization.