基于故障树方法的机动车燃油大气环境风险评价:以杭州市为例

由于城市化、工业化和机动车数量的快速增长,灰霾天气已成为中国许多大城市亟待解决的严重环境污染问题。大量石油燃料消耗产生的机动车尾气排放可能是引起城市灰霾污染的一个关键因素。以长江三角洲的代表性城市杭州市为具体案例,探索将安全工程领域的故障树方法应用在机动车燃油尾气排放大气环境风险评价和与灰霾天气的致因机理分析上。通过辨识导致城市机动车尾气过量排放的关键风险因子,构建了杭州市"灰霾天气–机动车尾气过量排放"的故障树。另外采用结构、概率以及临界重要度分析,对关键风险因子对顶上事件"灰霾天气–机动车尾气过量排放"的贡献和影响程度进行了定性和定量分析。分析结果表明,过量机动车使用,严重的交通堵塞、高污染机动车的不当使用以及监管不严是对杭州市机动车尾气过量排放影响较大的关键风险因子。可为城市机动车燃油环境风险因子评价以及管理提供一种简洁有效的方法和思路。     

基于事故树方法的城市灰霾的致因机理分析:以天津市为例

近年来,以PM2.5为特征的灰霾天气已成为中国许多城市极其严重的环境污染问题,对大气质量和人体健康具有严重的不良影响。由于煤炭在我国能源结构中占据主导地位,燃煤废气可能是导致灰霾污染的其中一个非常关键的影响因素。要进行大气污染防治,首先要对大气污染物的来源和致因机理进行研究。拟从系统方法论的新角度出发,以京津翼地区其中的代表城市天津为研究案例,探索将经典实用的事故树方法(FTA)应用在燃煤与灰霾的致因机理以及风险因子管理的新问题上。通过识别和辨明导致燃煤废气大量排放的直接和潜在原因,构建了"灰霾天气-燃煤废气过量排放"的事故树,基于最小割集、结构重要度、概率重要度以及临界重要度分析,定性、定量地评价了关键风险因子/事件对灰霾天气的贡献和影响。分析结果表明,能源结构不合理,没有合适可替代的清洁能源导致煤的大量燃烧是影响最大的关键风险因子。本工作可为灰霾天气的致因机理分析,风险因子防控以及管理提供一套科学有效的新思路和方法。     

基于事故树方法的城市灰霾的致因机理分析：以天津市为例

近年来,以PM_2.5为特征的灰霾天气已成为中国许多城市极其严重的环境污染问题,对大气质量和人体健康具有严重的不良影响。由于煤炭在我国能源结构中占据主导地位,燃煤废气可能是导致灰霾污染的其中一个非常关键的影响因素。要进行大气污染防治,首先要对大气污染物的来源和致因机理进行研究。拟从系统方法论的新角度出发,以京津翼地区其中的代表城市天津为研究案例,探索将经典实用的事故树方法（FTA）应用在燃煤与灰霾的致因机理以及风险因子管理的新问题上。通过识别和辨明导致燃煤废气大量排放的直接和潜在原因,构建了“灰霾天气-燃煤废气过量排放”的事故树,基于最小割集、结构重要度、概率重要度以及临界重要度分析,定性、定量地评价了关键风险因子/事件对灰霾天气的贡献和影响。分析结果表明,能源结构不合理,没有合适可替代的清洁能源导致煤的大量燃烧是影响最大的关键风险因子。本工作可为灰霾天气的致因机理分析,风险因子防控以及管理提供一套科学有效的新思路和方法。     

机动车尾气检测技术及污染防治对策

随着持续发展的汽车工业,我国城市大气已经受到汽车排放尾气的严重污染,相关部门也在加强机动车尾气检测,提高排放标准的严格程度,有效做好污染防治。主要对机动车尾气检测技术、机动车尾气污染防控对策两个方面做出了详细的分析和研究。     

鹰潭市环境空气质量现状、影响因素及防治建议

通过分析鹰潭市区环境空气质量现状、主要污染因子以及影响空气质量的主要因素,并提出了污染防治措施建议。结果表明,鹰潭市区环境空气污染天气以轻度污染为主,影响空气质量的主要因素有能源结构及工业布局不合理、城市扬尘、机动车尾气等。提出了加大产业结构调整、优化产业布局、加强机动车尾气和城市扬尘控制等措施。     

机动车尾气对环境的影响及其污染控制

介绍了机动车尾气排放对空气的污染以及对人体的危害,分析了我国机动车尾气排放的现状,提出了从加强技术攻关、完善管理体制、机动车总量控制、利用经济调控手段等角度控制机动车尾气排放建设绿色交通的措施和建议。     

灰霾成因及其监测方法的探讨

灰霾(Dust-Haze)是一种严重气溶胶污染导致的大气能见度降低(能见度一般低于10公里)现象。形成灰霾天气的大气气溶胶主要来源于自然排放和人类活动的排放。本文以广州地区的灰霾为案例,对灰霾的形成、现状、危害、监测方法、技术指标、以及如何应对灰霾等展开了论述。     

机动车对雾霾天气影响及防治措施

秋冬季节是我国发生大范围的雾霾天气和PM_(2.5)严重超标的时常季节。雾霾天气导致的空气质量下降给人们出行带来诸多不便,同时也危及人类健康。面临现今令人重重担扰的环境问题,中国科学院专家对雾霾天气和PM_(2.5)严重超标的情况进行分析,结果表明:机动车尾气排放污染是形成雾霾天气的第二大因素。因此,本文深入地分析了我国现在的环境监测体系中存在的环境问题及雾霾天气的成因,并且提出加强机动车管理是解决雾霾天气的必要措施之一。     

合肥市在用机动车排放特性的研究

为分析合肥市在用机动车排放水平和尾气检测标准实施情况,对合肥市机动车排气检测数据进行统计分析,计算得到尾气超标的车龄和行驶里程,得出合肥地区汽油车检测标准过低的结论,并给出合肥市机动车尾气检测排放标准计算限值。所得结论为估算合肥市机动车排放总量,提高机动车污染控制的决策和管理水平,以及评估机动车污染控制政策提供数据支持和理论指导。     

坚持变“堵”为“疏”根治烟气污染

今年以来,我国各地频发的灰霾天气严重危及百姓的生命健康。据监测统计,造成城市灰霾天气的主要元凶就是燃煤造成的烟气污染。为控制污染源,全国各地纷纷重权出击,采用控制煤炭消费总量、取消大气污染排放特权、制定更为严厉的大气污染排放限值等方法 "倒逼"产业转型升级。然而,上述种种措     

Review on formation mechanism analysis method and control strategy of urban haze in China

Due to the rapid urbanization and industrialization, and excessive consumption of fossil fuel, haze weather characterized by PM2.5 has become a severe pollution problem in major Chinese cities recently, which has harmful effect on the air quality, visibility, clime system and human health. To indicate suitable directions for the prevention and control of haze pollution, the pollutant source apportionment and formation mechanism of urban haze should be figured out firstly. In this work, we briefly review the frequently-used methods for PM2.5 source apportionment and formation mechanism analysis of urban haze based on normal perspective in recent years. Furthermore, based on the new perspective of systematic methodology, the utilization of fault tree approach for the causation mechanism analysis of urban haze is significantly introduced and discussed. Finally, the recent progress on controlling strategies of urban haze in China is also synoptically introduced and discussed. It is expected that more effective tool/method can be found, developed and employed for the causation mechanism analysis and risk management of urban haze in China.     

机动车主要尾气的光化学反应机理

随着近年来机动车数量的增加,机动车尾气污染已经成为城市光化学烟雾的重要来源。显然,如何控制机动车尾气的光化学反应已成为迫在眉睫的问题。综述了机动车排出的几种主要污染物的光化学反应机理,以期为防止光化学烟雾技术措施提供理论基础。     

我国机动车和燃油锅炉颗粒有机物排放特征

颗粒有机物是大气污染物的重要成分,对人体健康、雾霾形成具有重要影响。化石燃料燃烧是其最主要的来源之一。本研究选取我国不同燃油类型的机动车和燃油锅炉,利用稀释通道法采集了机动车及锅炉运行中排放的细颗粒物,并利用柱前衍生化GC-MS方法分析了其有机成分。在定量分析的约195种有机化合物中,机动车排放的理想示踪物霍烷和甾烷类物质均可被检出;芘/苯并[a]芘的值、苯并[ghi]苝和晕苯可以用来区分汽油车和柴油车排放;燃油锅炉排放的正构烷烃、正构烷酸、正构烷醇和多环芳烃与柴油车排放有相似之处,在颗粒物源解析研究中应单独考虑,否则可能会高估机动车的贡献;芳香酸可以用来区分燃油锅炉和其他污染源。与国外有机污染物排放源谱相比,我国机动车排放因子偏高,不同类别机动车排放因子具有较大差异。相同工况条件下,燃油类型对燃油锅炉排放因子有着较大影响。基于上述分析建立了我国不同类型机动车和燃油锅炉排放颗粒有机物的源成分谱。     

乌鲁木齐市机动车污染现状及防治对策研究

随着城市机动车保有量的不断增长,机动车尾气污染问题已经成为城市空气污染最重要的来源之一,控制机动车尾气污染也已经成为改善城市大气环境质量的当务之急。本文通过对乌鲁木齐市机动车保有量和机动车尾气污染的调查,分析了机动车尾气的污染现状,并借鉴其他地区的机动车尾气污染控制的经验,为改善乌鲁木齐市的大气环境质量提出防治对策。     

Chase Studies of Particulate Emissions from in-use New York City Vehicles

Emissions from motor vehicles are a significant source of fine particulate matter (PM) and gaseous pollutants in urban environments. Few studies have characterized both gaseous and PM emissions from individual in-use vehicles under real-world driving conditions. Here we describe chase vehicle studies in which on-road emissions from individual vehicles were measured in real time within seconds of their emission. This work uses an Aerodyne aerosol mass spectrometer (AMS) to provide size-resolved and chemically resolved characterization of the nonrefractory portion of the emitted PM; refractory materials such as elemental carbon (EC) were not measured in this study. The AMS, together with other gas-phase and particle instrumentation, was deployed on the Aerodyne Research Inc. (ARI) mobile laboratory, which was used to “chase” the target vehicles. Tailpipe emission indices of the targeted vehicles were obtained by referencing the measured nonrefractory particulate mass loading to the instantaneous CO₂ measured simultaneously in the plume. During these studies, nonrefractory PM_1.0 (NRPM₁) emission indices for a representative fraction of the New York City Metropolitan Transit Authority (MTA) bus fleet were determined. Diesel bus emissions ranged from 0.10 g NRPM₁/kg fuel to 0.23 g NRPM₁/kg, depending on the type of engine used by the bus. The average NRPM₁ emission index of diesel-powered buses using Continuously Regenerating Technology (CRT?) trap systems was 0.052 g NRPM₁/kg fuel. Buses fueled by compressed natural gas (CNG) had an average emission index of 0.034 g NRPM₁/kg Fuel. The mass spectra of the nonrefractory diesel aerosol components measured by the AMS were dominated by lubricating oil spectral signatures. Mass-weighted size distributions of the particles in fresh diesel exhaust plumes peak at vacuum aerodynamic diameters around 90 nm with a typical full width at half maximum of 60 nm.     

柴油车尾气净化催化技术进展

介绍了柴油车尾气排放的特性及主要污染物;从颗粒物的催化再生技术、贫燃条件下NOx的选择性催化还原技术以及氧化催化技术等几个方面对柴油车尾气净化技术;尤其是催化技术进行了探讨;并提出了未来柴油车用催化剂的发展方向。     

流化催化裂化(FCC)催化剂跑损机制及故障树分析

炼油厂中流化催化裂化（FCC）装置催化剂跑损的故障原因分析多数来自现场工程师,在故障机理方面少有报道。为了解决这一问题,本文利用故障树分析方法（FTA）,研究FCC装置催化剂跑损机制。采用催化剂跑损为顶事件,结合跑损途径和跑损机理,确定FCC装置故障、操作工艺异常和催化剂颗粒物性3个因素作为中间事件,并通过逐层向下深入分析,确定诸如翼阀磨损等21个因素作为底事件,建立催化剂跑损故障树模型。根据FCC装置故障树风险分析,得到任何一个底事件出现都有可能导致顶事件发生,且对FCC装置催化剂跑损的贡献度相同。研究结果表明：利用FTA方法可以更深层次了解装置跑剂原因,对考察FCC装置催化剂跑损机理具有指导意义,并提出了相应的故障判定流程和跑剂预防措施。     

Effect of Soil Type and Momentum on Unpaved Road Particulate Matter Emissions from Wheeled and Tracked Vehicles

Excluding windblown dust, unpaved road dust PM ₁₀ emissions in the US EPA's 2002 National Emission Inventory account for more than half of all PM ₁₀ emissions in the arid states of the western U.S. (i.e., CA, AZ, NV, NM, and TX). Despite the large size of the source, substantial uncertainty is associated with both the vehicle activity (i.e., number of kilometers traveled at a particular speed) and the emission factors (i.e., grams of PM ₁₀ per kilometer traveled). In this study, emission factors were measured using the flux tower method for both tracked and wheeled military vehicles at three military bases in the Western U.S. Test vehicle weights ranged from 2400 kg to 60,000 kg. Results from both previously published and unpublished field studies are combined to link emission factors to three related variables: soil type, vehicle momentum, and tred type (i.e., tire or track). Current emission factor models in US EPA's AP-42 Emission Factor Compendium do not factor both speed and weight into unpaved road emission factor calculations. Tracked vehicle emission factors from Ft. Carson, CO, and Ft. Bliss, TX were related to vehicle momentum (speed ? mass) with ratios ranging from 0.004–0.006 (g-PM vkt^{? 1})/(kg m s^{? 1}). For similar vehicle momentum, wheeled vehicles emitted approximately 2 to 4 times more PM ₁₀ than tracked vehicles. At Yakima, WA, tracked vehicle PM ₁₀ emission factors were substantially higher (0.38 (g-PM vkt^{? 1})/(kg m s^{? 1})) due to the unique volcanic ash soil characteristics (48% silt). Results from PI-SWERL, a portable wind tunnel surrogate, are presented to assess its utility to predict unpaved road dust emissions without the deployment of flux tower systems. PI-SWERL showed only a factor of 6 variation between sites in comparison with the 60-fold variation as measured by the flux towers.     

EXHAUST EMISSIONS OF PAHs OF PASSENGER CARS

Exhaust emissions of 16 PAHs, listed by the U.S. Environmental Protection Agency (USEPA) as priority pollutants, are measured using a vehicle bench on a sample of passenger cars. Thirteen gasoline vehicles and 17 diesel vehicles are tested, complying with ECE 1504 to Euro 3 emission standards, according to three real-world driving cycles based on European driving behavior (2 urban and 1 motorway). HPLC with fluorometric detection is used for their quantification.

The effect of cold or hot start is put to the fore with the short urban INRETS cycle.

The particle and gas-phase distribution is studied for all the vehicles and the hot driving cycles.

In this study, the cars' emissions are shown to be reduced, according to the legislative level (Euro-1, 2, 3 …). The majority of volatile PAHs is mainly observed in the gas phase whereas the less volatile and carcinogenic PAHs are especially adsorbed on particles.