Evaluation of the International Vehicle Emission （IVE） model with on-road remote sensing measurements

Intemational Vehicle Emissions （IVE） model funded by U.S. Environmental Protection Agency （USEPA） is designed to estimate emissions from motor vehicles in developing countries. In this study, the IVE model was evaluated by utilizing a dataset available from the remote sensing measurements on a large number of vehicles at five different sites in Hangzhou, China, in 2004 and 2005. Average fuel-based emission factors derived from the remote sensing measurements were compared with corresponding emission factors derived from IVE calculations for urban, hot stabilized condition. The results show a good agreement between the two methods for gasoline passenger cars＇ HC emission for all 1VE subsectors and technology classes. In the case of CO emissions, the modeled results were reasonably good, although systematically underestimate the emissions by almost 12%-50% for different technology classes. However, the model totally overestimated NOx emissions. The IVE NOx emission factors were 1.5-3.5 times of the remote sensing measured ones. The IVE model was also evaluated for light duty gasoline truck, heavy duty gasoline vehicles and motor cycles. A notable result was observed that the decrease in emissions from technology class State II to State I were overestimated by the IVE model compared to remote sensing measurements for all the three pollutants. Finally, in order to improve emission estimation, the adjusted base emission factors from local studies are strongly recommended to be used in the IVE model.     

单辆机动车二次扬尘量化计算的实验研究

在此针对影响机动车行驶过程二次扬尘的主要因素 ,采用正交设计法进行实验分析 ,提出机动车单车行驶过程二次扬尘TSP及PM1 0 浓度量化计算模型及相应的排放因子     

负载对实际道路重型柴油车排放的影响研究

利用车载测试系统对重型柴油货车空载、50％负载和100％负载不同负载情况下在实际道路的排放进行测试,基于测试数据分析负载对重型柴油货车排放CO、HC、NOx和微小颗粒物(PM)等4种污染物的影响.不同速度区间和行驶模式下负载对排放的影响分析表明,在有负载时,大多数工况下4种污染物排放呈现增加趋势,但各速度区间和行驶模式下的增幅不尽相同,部分工况出现下降.空载时测试柴油车基于新欧洲行驶循环测试(NEDC)工况的标准化CO、HC、NOx和PM排放因子分别为3.38、0.39、6.27、0.39 g/km.对于柴油车重点污染物NOx和PM而言,与空载相比,50％负载时分别增加43％和59％,100％负载时分别增加62％和44％.     

机动车单车扬尘浓度分布规律的模拟

为了掌握汽车扬尘中PM10污染分布特征,采用数值模拟的方法对汽车扬尘PM10浓度分布规律及其影响因素进行了研究,分析了车速、积尘负荷对汽车扬尘PM10浓度的影响.结果表明,车速与扬尘运移速率成正比,且车速在20～60 km/h范围内与扬尘高度近似成线性分布;积尘负荷与汽车扬尘PM10平均浓度同比例变化.     

在用轻型汽油车排放随行驶里程劣化规律分析

基于佛山市3.5万条简易稳态工况(ASM)下的尾气排放检测数据,通过分类统计和线性拟合方法分析在用轻型汽油车的污染物排放浓度随行驶里程的劣化规律。分析结果表明,该地区轻型汽油车污染物排放浓度主要分布于低值区间,超过85%的样本数据低于最低排放限值;车辆排放劣化特征随行驶里程呈规律性变化,行驶里程在0~5万km时污染物排放缓慢增长,5万~16万km时呈快速线性增长,16万km后震荡缓慢增长;行驶里程在16万km前,不同车型的排放特征存在一定差异,其中轻型货车和轻型客车的排放浓度高、劣化速度快;CO、HC、NO随行驶里程的劣化规律可用线性增长模型表示。本研究结论可为预测机动车污染变化趋势、完善在用车检查/维护制度、高排放车辆识别和淘汰等方面提供理论支持。     

Variation characteristics of fine particulate matter and its components in diesel vehicle emission plumes

A rapid reaction occurs near the exhaust nozzle when vehicle emissions contact the air. Twenty diesel vehicles were studied using a new multipoint sampling system that is suitable for studying the exhaust plume near the exhaust nozzle. The variation characteristics of fine particle matter (PM_2.5) and its components in diesel vehicle exhaust plumes were analyzed. The PM_2.5 emissions gradually increased with increasing distance from the nozzle in the plume. Elemental carbon emissions remained basically unchanged, organic carbon and total carbon (TC) increased with increasing distance. The concentrations of SO₄^2?, NO₃^? and NH₄⁺ (SNA) directly emitted by the vehicles were very low but increased rapidly in the exhaust plume. The selective catalytic reduction (SCR) reduced 42.7% TC, 40% NO₃^? emissions, but increased 104% SO₄^2? and 36% NH₄⁺ emissions, respectively. In summary, the SCR reduced 29% primary PM_2.5 emissions for the tested diesel vehicles. The NH₄NO₃ particle formation maybe more important in the plume, and there maybe other forms of formation of NH₄⁺ (eg. NH₄Cl). The generation of secondary organic carbon (SOC) plays a leading role in the generation of secondary PM_2.5. The SCR enhanced the formation of SOC and SNA in the plume, but comprehensive analysis shows that the SCR more enhanced the SNA formation in the plume, which is mainly new particles formation process. The inconsistency between secondary organic aerosol (SOA) and primary organic aerosol definitions is one of the important reasons for the difference between SOA simulation and observation.     

固相微萃取技术在苯胺等突发性水环境污染事故中的应用

建立了固相微萃取与车载气相色谱-质谱联用技术现场快速定量分析突发性水环境污染事故中的硝基苯、苯酚、苯胺3种半挥发性有机物的方法。选用PA萃取纤维,调节水样p H为8.5,加入30%的氯化钠,45℃顶空萃取30 min可得最佳萃取效果。在最佳实验条件下,硝基苯、苯酚、苯胺的方法检出限分别为0.68、3.2、4.88μg/L;平行测定7次的相对标准偏差分别为5.37%、8.31%、2.86%;3种化合物的相关性系数均大于0.99;对实际样品测定的加标回收率在61.1%~120%。     

京津冀地区一次浮尘过程的车载激光雷达走航观测

利用双波长三通道激光雷达与车载激光雷达,针对2018年3月28日京津冀区域的浮尘天气过程,分别进行了定点垂直观测与车载走航观测,对这次浮尘天气中沙尘的源地、沙尘气溶胶的时空分布、沙尘的传输路径与传输方式进行了综合分析。位于北京的激光雷达监测到28日凌晨开始,沙尘气溶胶与近地面污染物混合,受沙尘影响近地面污染物浓度迅速升高。北京到沧州的车载激光雷达走航观测结果显示,沙尘气溶胶先向南传输到京津冀南部区域,随后向西南方向传输,同时观测到京津冀区域上空1. 5 km左右存在沙尘传输带。结果表明,使用车载激光雷达走航观测,结合定点垂直激光雷达与其他地面监测数据,能可靠地观测到沙尘过程中颗粒物的时空变化特征。     

典型街道环境空气质量分析

根据对深南东路环境空气的监测及车流量、气象条件的调查,分析机动车及气象因素对深圳市环境空气质量的影响。根据分析可知,机动车尾气是深圳市环境空气中污染物的主要来源,但污染程度不断变化的主要原因是风速,深圳市环境空气中污染物浓度与风速有着非常显著的负相关。     

高排放车遥感筛选在台湾的应用

机动车尾气遥感监测是一项较新的技术。文章介绍了台湾地区在机动车尾气遥感监测法规、标准制订、实施方面的成功经验,以及我国其他大城市可以从中借鉴的经验。