长三角典型城市公交车实际道路细颗粒物排放测试

为研究长三角典型城市公交车细颗粒物排放特征，采用便携式排放测试系统（PEMS），对上海、杭州和苏州三大城市的8辆典型城市公交车开展实际道路细颗粒物排放实验。研究结果表明：长三角典型城市车辆的实际道路平均车速为22.7 km/h，怠速比例为20.4%，加减速比例为54.5%；在稳态行驶工况下，随车速增大，公交车颗粒物质量及数量排放呈逐渐增大趋势；在20 km/h车速范围内，上海国III、国IV和苏州国III公交车颗粒数浓度呈双峰粒径分布，其他公交车均为单峰分布；随比功率的增大，公交车颗粒质量呈逐渐增大的趋势，国IV公交车颗粒数量呈先下降再增大趋势，国III公交车颗粒数量呈上升趋势；公交车颗粒质量综合排放因子为0.8~189 mg/km，颗粒数量综合排放因子为6.2×10¹²~9.6×10¹⁴#/km。     

天津市春季典型道路积尘负荷分布特征

道路积尘负荷表征路面清洁程度,是道路扬尘排放清单中一个十分重要的参数,也是各地环境管理的一个重要方面。根据AP-42道路扬尘排放因子模型,2015年春季用真空吸尘法采集了天津市11条道路的扬尘样品,得到了不同道路类型以及不同车道的积尘负荷,并分析了积尘负荷的变化规律。结果表明:天津市春季非机动车道和机动车道慢车道的积尘负荷分别为0.282 0~1.064 5 g/m~2和0.050 4~0.173 9 g/m~2;5种道路类型的非机动车道的积尘负荷中位值均大于机动车慢车道积尘负荷的中位值;对于不同道路类型积尘负荷而言,非机动车道从大到小顺序依次为次干道主干道环线支路快速路,机动车道慢车道从大到小顺序依次为次干道环线主干道支路快速路;东西走向和南北走向道路两侧积尘负荷差异均无统计学意义。     

Vehicular particulate matter emissions in road tunnels in Sao Paulo, Brazil

In the metropolitan area of S?o Paulo, Brazil, ozone and particulate matter (PM) are the air pollutants that pose the greatest threat to air quality, since the PM and the ozone precursors (nitrogen oxides and volatile organic compounds) are the main source of air pollution from vehicular emissions. Vehicular emissions can be measured inside road tunnels, and those measurements can provide information about emission factors of in-use vehicles. Emission factors are used to estimate vehicular emissions and are described as the amount of species emitted per vehicle distance driven or per volume of fuel consumed. This study presents emission factor data for fine particles, coarse particles, inhalable particulate matter and black carbon, as well as size distribution data for inhalable particulate matter, as measured in March and May of 2004, respectively, in the Janio Quadros and Maria Maluf road tunnels, both located in S?o Paulo. The Janio Quadros tunnel carries mainly light-duty vehicles, whereas the Maria Maluf tunnel carries light-duty and heavy-duty vehicles. In the Janio Quadros tunnel, the estimated light-duty vehicle emission factors for the trace elements copper and bromine were 261 and 220 microg km(-1), respectively, and 16, 197, 127 and 92 mg km(-1), respectively, for black carbon, inhalable particulate matter, coarse particles and fine particles. The mean contribution of heavy-duty vehicles to the emissions of black carbon, inhalable particulate matter, coarse particles and fine particles was, respectively 29, 4, 6 and 6 times higher than that of light-duty vehicles. The inhalable particulate matter emission factor for heavy-duty vehicles was 1.2 times higher than that found during dynamometer testing. In general, the particle emissions in S?o Paulo tunnels are higher than those found in other cities of the world.     

Monitoring of heavy metal levels in roadside dusts of Thessaloniki, Greece in relation to motor vehicle traffic density and flow

In recent years, the level of heavy metal pollution in urban areas has been of considerable concern. The principal source has been attributed to the motor vehicle and increasing inner city congestion, which has lead to a change and enlargement of transport stop-start zones. These areas of high traffic density are associated with an increased release of heavy metals into the adjacent residential or commercial areas. Seventy-five roadside dust samples were collected throughout the inner city and by-pass motorway areas of Thessaloniki, Northern Greece. Samples were taken from arterial, major and minor roads, as well as the ring road, to compare and contrast the levels of heavy metals, namely Cu, Zn, Cd, Mn and Pb. Flame Atomic Absorption Spectroscopy (FAAS) was developed to quantitatively determine concentrations of both total element and geochemical fractionation, within the two dust particulate fraction sizes <75 microm and 75-125 microm. Acid digestion using Aqua Regia (3:1 conc. HCl:HNO(3)) was employed for the total elemental analysis, a method that was validated through the use of certified reference materials (CRM). Fractionation studies involved a three-step sequential extraction method performed on five selected samples (representatives of high, mid and low total elemental concentrations). The resultant solutions were analysed for lead and zinc levels to ascertain fractionation throughout the different geochemical fractions, thus assessing bioavailability.It was found that congestion/stop-start traffic patterns did influence and have led to increased levels of heavy metal deposition along inner city roads compared to levels observed on the new relief ring road. Dust particulate fraction sizes were only found to show statistically significant differences in cadmium and manganese, at the probability P < 0.001 or 99.9% confidence limit. Both Cd and Mn showed higher total levels in the smaller fraction sizes (<75 microm), implying that their major release source is exhaust emissions. There were no significant differences in the other elements, at the P > 0.05 or 95% confidence limit. Road type was seen to have little affect on cadmium and manganese, though lead, copper and zinc were all found to show higher levels on the inner city routes. This can be related back to the wear-and-tear of vehicle components as a result of the stop-start traffic patterns (brake pads etc). Both Pb and Zn have shown to be in chemical forms that are bio available to ecosystems.     

匀速行驶小型载客汽车噪声频谱研究

系统测量了5辆小型载客汽车分别以20~100 km/h匀速行驶时的车外噪声频谱,得到了低、中、高各频段声压级随车速的变化关系,进一步与城市道路交通噪声频谱相比较,为从声源上控制城市道路交通噪声提供有力的参考依据。     

Mean Vehicle Speed Distributions for the Spatiotemporal Estimation of Exhaust Emissions

Link Emissions Models estimate traffic-related air pollution emissions at the individual road link level and inform governmental policies for air quality management. The current South Australian Link Emissions Model (CLEM) assumes constant spatiotemporal traffic flow at a single fixed mean speed, a potential limitation as the variability of exhaust emissions with vehicle speed has been established in the literature.We extend CLEM to eliminate the assumption of constant traffic flow, through the derivation of mean Australian vehicle speed distributions for different road types. Specifically, we successfully model the vehicle speed profile data from the second National In-Service Emissions study using Nearest Neighbour Kernel Density Estimation. We propose a mean speed Distribution Link Emissions Model (DLEM) for exhaust emission estimation based on the derived mean speed distributions. DLEM is an augmented, enhanced version of CLEM, accommodating a range of vehicle speeds and road types. The performance of the extended model, DLEM, is analysed in comparison to the current model, CLEM, through a case study analysis of vehicle exhaust emissions on a typical arterial road in Adelaide, South Australia. Results indicate use of DLEM and, by extension, mean vehicle speed distributions, has a strong impact on emission estimation. In particular, the fixed speed model, CLEM, may be substantially underestimating exhaust emissions of carbon monoxide, non-methane volatile organic compounds and particulate matter less than 2.5 μm in diameter. These are common exhaust pollutants that have been extensively linked with adverse health effects including respiratory morbidity and premature mortality.     

A Simple Model for Urban Background Pollution

A simple urban background pollution model is presented. Contributions from the individual area sources, subdivided into a grid net of a resolution of 2km × 2km, are integrated along the wind direction path assuming linear dispersion with the distance to the receptor point. Horizontal dispersion is accounted for by averaging the calculated concentrations over a certain, wind speed dependent wind direction sector, centred on the average wind direction. Formation of the nitrogen dioxide due to oxidation of nitrogen monoxide by ozone is calculated using a simple chemical model based on assumption of a photochemical equilibrium on the time scale of the pollution transport across the city area. The rate of entrainment of fresh rural ozone is governed by this time scale. The model is suitable for calculations of urban background when the dominating source is the road traffic. For this source the emissions take place at ground level, and a good approximation is to treat the emissions as area sources, but with an initial vertical dispersion determined by the height of the buildings.     

Modelling heavy metal fluxes from traffic into the environment

A new method is presented which allows emissions of traffic into the environment to be described as a function of road distance. The method distinguishes different types of emissions (runoff, spray and drift), which are determined by measurements and mass balances of a specified road section. The measurement of two-dimensional pollutant concentrations in the road shoulder is an important part of the method. In a case study performed at Burgdorf, Switzerland, the method was applied to the determination of the spatial distribution of heavy metal emissions. The results show that between 36 and 65% of the heavy metals Cd, Cr, Cu, Pb and Zn are present in runoff and spray and between 35 and 64% are dispersed diffusely in the environment (defined as drift). The runoff infiltrates into the vegetated road shoulder up to a distance of approx. 1 m from the road. The distribution of spray shows a maximum at 1 m and decreases steadily up to a distance of 5 m. This information can serve as a basis for the quantitative evaluation of road-runoff treatment scenarios. Although the results of the Burgdorf study are case-specific, several general guidelines for the reduction of traffic-related emissions can be derived from it.     

Monitoring Of Vehicles Derived Particulates Using Magnetic Properties Of Leaves

Biomonitoring of vehicle-derived particulates is conducted by taking magnetic measurements of roadside tree leaves. Remanent magnetization (IRM_{300 mT}) of more than 400 Delbergia sissoo leaves was determined and IRM_{300 mT} normalized for the leaf area. The normalized 2-D magnetization as shown by results is dominantly controlled by the tree's distance to the road. The spatial and temporal variations of vehicle-derived particulates were mapped using magnetic analysis. 2D-magnetizations values were higher for leaves collected adjacent to major road sections than for those from village road suggesting vehicle emissions, rather than resuspended road dust, as the major cause of magnetic particles of roadside tree leaves. Vehicles derived particulates are responsible for tree leaf magnetism, and the leaf magnetizations values fall significantly from high values proximal to the roadside to lower values at the distal side. This suggests the ability of trees to reduce particulates concentrations in the atmosphere. The rainfall produces a net decrease in the leaf magnetic dust loadings.     

Antimony speciation in soil samples along two Austrian motorways by HPLC-ID-ICP-MS

Distribution of antimony and its inorganic species in soil samples along two traffic routes (A14, Rankweil and S36, Knittelfeld) in Austria was determined, since vehicle emissions are an important anthropogenic source of Sb in soil. The samples were taken along three parallel lines at about 0.2, 2 and 10 m distances from the edge of the road and in two depths range (0-5 and 5-10 cm from the soil surface). The optimized extraction was carried out using 100 mmol L(-1) citric acid at pH 2.08 applying an ultrasonic bath for 45 min at room temperature. Speciation analyses were done using on-line isotope dilution after a chromatographic separation of Sb species. Results of the two traffic routes confirmed significant accumulations of Sb at surface (0-5 cm depth) exceeding the natural background values by more than ten times at the S36 or four times at the A14. Concentrations of the extractable inorganic species decreased to natural background levels within a few meters from the edge of the traffic lane. The predominant Sb species was Sb(V). The Sb(III) concentrations at 5-10 cm depths range are nearly constant with distance from the edges of the two roads. Magnetic susceptibility data of all soil samples show the same distribution pattern as Sb and Sb(V) concentrations along the two traffic roads with an excellent correlation. This is an evidence for an anthropogenic source of Sb such as abrasions of motor vehicles surfaces or braking linings. The input of Sb and its inorganic species at one of the sampling sites (Knittelfeld) in samples taken in 2002 and in those taken recently (2005) was monitored. An increase in Sb (>or=30%), Sb(v)(>or=51%) and Sb(iii)(>or=10%) concentrations was only observed near the edge (相似文献   

CALRoads模式在上海市典型道路CO扩散预测中的应用

根据上海市市区、郊区典型主干道的气象条件、车流量、车型比例,以及CO小时质量浓度的监测资料,采用CALRoads模式中CALINE4和CAL3QHC模块,对郊区主干道和市区典型路口的适用条件分别进行了验证.结果表明,在稳定的气象条件下,CALINE4模式在模拟周围相对空旷主干道附近的CO质量浓度时,具有较好的结果,将CAL3QHC模式应用于市区典型交叉口,可以得到同监测值相对吻合的模拟结果,但准确性低于郊区.应用CALRoads模型对未来城郊典型道路附近CO高峰小时质量浓度的发展趋势进行了预测,并基于情景分析给出了减少交通污染的对策建议.     

Spatial & temporal variations of PM10 and particle number concentrations in urban air

The size of particles in urban air varies over four orders of magnitude (from 0.001 μm to 10 μm in diameter). In many cities only particle mass concentrations (PM10, i.e. particles <10 μm diameter) is measured. In this paper we analyze how differences in emissions, background concentrations and meteorology affect the temporal and spatial distribution of PM10 and total particle number concentrations (PNC) based on measurements and dispersion modeling in Stockholm, Sweden. PNC at densely trafficked kerbside locations are dominated by ultrafine particles (<0.1 μm diameter) due to vehicle exhaust emissions as verified by high correlation with NOx. But PNC contribute only marginally to PM10, due to the small size of exhaust particles. Instead wear of the road surface is an important factor for the highest PM10 concentrations observed. In Stockholm, road wear increases drastically due to the use of studded tires and traction sand on streets during winter; up to 90% of the locally emitted PM10 may be due to road abrasion. PM10 emissions and concentrations, but not PNC, at kerbside are controlled by road moisture. Annual mean urban background PM10 levels are relatively uniformly distributed over the city, due to the importance of long range transport. For PNC local sources often dominate the concentrations resulting in large temporal and spatial gradients in the concentrations. Despite these differences in the origin of PM10 and PNC, the spatial gradients of annual mean concentrations due to local sources are of equal magnitude due to the common source, namely traffic. Thus, people in different areas experiencing a factor of 2 different annual PM10 exposure due to local sources will also experience a factor of 2 different exposure in terms of PNC. This implies that health impact studies based solely on spatial differences in annual exposure to PM10 may not separate differences in health effects due to ultrafine and coarse particles. On the other hand, health effect assessments based on time series exposure analysis of PM10 and PNC, should be able to observe differences in health effects of ultrafine particles versus coarse particles.     

Lead,cadmium, arsenic and zinc in the ecosystem surrounding a lead smelter

A lead smelter has been operating at Belledune in the province of New Brunswick, in eastern Canada, since 1966. This paper presents data on the concentrations of the four primary metals emitted from the smelter — lead, cadmium, arsenic and zinc — which were measured in the terrestrial environment near the smelter and the concentrate transport route. Deposition of these metals to the snowpack and the uptake by grass forage are discussed in relation to non-regulatory guidelines, toxicity and atmospheric emissions. A 1992 snowpack transect survey extending 0.5–40 km northwest, southeast and south of the smelter revealed lead concentrations of 2–3193 ppb, cadmium <0.10–49.7 ppb, arsenic <3.0–72.0 ppb, and zinc 3–401 ppb. Deposition estimates within this zone for lead were between 0.046 and 20.1 kg/ha/yr, cadmium <0.007 and 313 g/ha/yr, arsenic <0.016 and 453 g/ha/yr and zinc 0.020 and 2.52 kg/ha/yr. Concentrations of these metals in the snowpack were highest within 3 km of the smelter and were detectable at greater distances SE of the smelter. Lead was dispersed greater distances from the smelter than cadmium or arsenic. Snowpack samples collected within 5–20 m of the railway contained 140–7270 ppb of lead, 0.4–36.9 ppb of cadmium, <3.0–72.0 ppb of arsenic and 41–13100 ppb of zinc. Grass forage sampled within 0.6–16 km of the smelter contained lead 5–152 ppm, cadmium 0.10–4.1 ppm, and zinc 22–154 ppm. Highest concentrations of lead, cadmium and zinc in grass forage were found were found within 2.2 km of the smelter. Grass forage collected within 10–70 m of the railway contained lead 13–288 ppm, cadmium 0.4–1.3 ppm and zinc 98–831 ppm.     

佛山市交通CO2排放及低碳出行对策

以佛山市2012年数据为基础,结合COPERT模型,分析了车型种类、排气量、燃油类型、排放水平等对CO2排放因子的影响规律,探讨了不同车型组成与排放水平下的CO2排放分担率,讨论并评估了佛山市的低碳交通出行对策。结果表明:排放水平对CO2排放因子的影响不明显,除重型客车与公交车,燃油类型对CO2排放因子的影响亦不明显,各车型的CO2排放因子随着排气量的增加而增加;当佛山市机动车平均行驶速度提高至55 km/h时,每辆车CO2综合排放因子可达最小值125.73 g/km;轻型客车和摩托车的CO2排放量最大,分别为1469 493 t/a和394 174.3 t/a,分担率分别为52.1%和14.0%;不同排放水平的载客车CO2排放分担率从大到小排序依次为:国I国0国Ⅱ国Ⅲ国Ⅳ,分别为34.7%、22.0%、21.2%、17.5%及4.6%。     

测点高度对道路交通噪声监测数据的影响

通过在4城市对132条道路进行了道路交通噪声测点高度试验,系统分析了测点高度从手工监测的1.2 m向自动监测的4.5 m转化后,在不同道路情况对道路交通噪声监测数据的影响。结果表明,测点高度提高后监测结果变化在±3 dB(A)以内。待测道路的车道数和测点与机动车道的距离是其主要影响因素。对两测点高度进行对比,4.5 m高度噪声值随水平距离增加衰减较小,测量结果更稳定。     

Magnetic properties of the road dusts from two parks in Wuhan city, China: implications for mapping urban environment

Magnetic parameters and heavy metal concentrations of road dusts collected from two parks with distance about 16 km in Wuhan city, China, were measured. The Guishan Park is circled by main roads with heavy traffic, and the Moshan Park is located on the downwind hills of steelworks and a power plant. Mean values of magnetic susceptibility (??) and saturation magnetization (M _s) of the dusts from the Moshan Park are 1.31 and 1.57 times those from the Guishan Park, respectively. Their magnetic mineralogy is dominated by pseudo-single domain magnetite; however, minor hematite was also identified in those from the Guishan Park. The dominant sources of non-natural magnetic particles and heavy metals were inferred as windblown emissions from the steelworks and the power plant for the Moshan Park, and road/railway traffics for the Guishan Park, respectively. Spatial variation in magnetic properties of road dust in the two parks and their different magnetic behavior propose that the magnetic measurements are sensitive to the different pollutant origins, as well as the urban environment, and that magnetic techniques have a high efficiency in mapping urban environment. Correlation between magnetic parameters and heavy metal concentrations is strongly site-specific: strong correlations were observed in the Moshan Park with correlation coefficients generally higher than 0.800, whereas correlations are poor in the Guishan Park. Therefore, it is strongly recommended that these relationships should be examined thoroughly before magnetic mapping.     

无锡市国控环境空气自动监测站点周边裸土分布高分辨率遥感监测

以无锡市为研究区,使用过境时间相近的哨兵2号Sentinel-2和Landsat8影像,综合使用NDSI、NDISI、MNDWI、LST等指数进行决策树分类,获得10 m高空间分辨率的土地利用分类结果和裸土分布,裸土提取精度达到94.13%。统计了无锡市与8个国控环境空气自动监测站点1、2、3 km缓冲区范围内的裸土分布情况,并与各站点监测的大气颗粒物浓度进行相关性分析。结果表明,国控环境空气自动监测站点周边裸土面积对颗粒物浓度有较大影响,其中对PM₁₀浓度的影响明显大于PM_2.5;相比于1 km和3 km,2 km缓冲区范围内的裸土面积对PM₁₀浓度的影响最大,建议环境管理部门重点关注无锡地区国控监测站点周边2 km范围内的裸土扬尘源分布情况。     

2016—2018年北京城市湿地遥感监测分析

为全面了解北京城市湿地的现状及近年来的动态变化情况，利用高分辨率卫星遥感数据，综合运用GIS技术与景观生态学方法，定量分析了北京市6环内的湿地空间格局。结果表明，北京6环内城市湿地以河流湿地和湖库湿地为主；2016—2018年间湿地面积有所下降，2年间减少了126.58 hm²，主要转化为草地，少量转化为建设用地和林地；由于城市外围的开发建设强度较大，5-6环湿地被侵占面积相对较大，而4环内湿地面积的波动较小；2016—2018年，北京城市湿地的斑块密度增加，平均斑块面积有所减小，表明湿地斑块随时间变化呈破碎化的趋势，且从城市中心向城市边缘，湿地斑块的破碎化程度增强。     

New research assessing the effect of engine operating conditions on regulated emissions of a 4-stroke motorcycle by test bench measurements

In the latest years the effect of powered two-wheelers on air polluting emissions is generally noteworthy all over the world, notwithstanding advances in internal combustion engines allowed to reduce considerably both fuel consumption and exhaust emissions of SI engines. Nowadays, in fact, these vehicles represent common means of quotidian moving, serving to meet daily urban transport necessities with a significant environmental impact on air quality. Besides, the emissive behavior of the two-wheelers measured under fixed legislative driving standards (and not on the local driving conditions) might not be sufficiently representative of real world motorcycle riding.The purpose of this investigation is a deeper research on emissive levels of in-use motorcycles equipped with last generation SI engines under real world driving behavior. In order to analyze the effect of vehicle instantaneous speed and acceleration on emissive behavior, instantaneous emissions of CO, HC and NO_X were measured in the exhaust of a four-stroke motorcycle, equipped with a three-way catalyst and belonging to the Euro-3 legislative category. Experimental tests were executed on a chassis dynamometer bench in the laboratories of the National Research Council (Italy), during the Type Approval test cycle, at constant speed and under real-world driving cycles. This analytical-experimental investigation was executed with a methodology that improves vehicles emission assessment in comparison with the modeling approaches that are based on fixed legislative driving standards. The statistical processing results so obtained are very useful also in order to improve the database of emission models commonly used for estimating emissions from road transport sector, then they can be used to evaluate the environmental impact of last generation medium-size motorcycles under real driving behaviors.     

Geochemical behavior of heavy metals in a Zn–Pb–Cu mining area in the State of Mexico (central Mexico)

The geochemical behavior of zinc, lead and copper from sulfidic tailings in a mine site with potential to generate acidic drainage (pyrite (55%) and sphalerite (2%)) is reported in this paper. The mining area is divided in two zones, considering the topographic location of sampling points with respect to the tailings pile: (a) outer zone, out of the probable influence of acid mine drainage (AMD) pollution, and (b) inner zone, probably influenced by AMD pollution. Maximum total ions concentrations (mg/L) measured in superficial waters found were, in the outer zone: As (0.2), Cd (0.9), Fe (19), Mn (39), Pb (5.02), SO4(2-) (4650), Zn (107.67), and in the inner zone are As (0.1), Cd (0.2), Fe (88), Mn (13), Pb (6), SO4(2-) (4,880), Zn (46). The presence of these ions that exceeding the permissible maximum limits for human consume, could be associated to tailings mineralogy and acid leachates generated in tailings pile.