Trends in exhaust emissions from in-use Mexico City vehicles, 2000–2006. A remote sensing study

A remote sensing study was conducted in year 2006 in four locations of the Metropolitan Area of Mexico City (MAMC). Two of the sites were the same studied back by us in year 2000 and by others in year 1994. A database was compiled containing 11,289 valid measurements for the carbon monoxide (CO), total hydrocarbons (THC), and nitric oxide (NO) exhaust vehicles emissions. Valid measurements were binned for each pollutant by the vehicle specific power (between −5 and 20 kW tonne⁻¹) for the 2000 and 2006 databases. The mean average CO, THC, and NO emissions for year 2006 were determined to be 1.10 ± 0.18 vol.%, 299 ± 88.4 ppm, and 610 ± 115.0 ppm, respectively. Matching the vehicle driving patterns of the fleet measured in year 2000 with the emissions factors obtained in this work, allows estimating the trends in the exhaust emissions of vehicles in the MAMC. The adjusted results of the remote sensing study performed in year 2006 shows that the fleet has decrease 22% in CO and 17% in NO emissions, with small change in total hydrocarbons emissions. The improvements could be related with the introduction in year 2001 of vehicles that met tighter emissions standards, particularly for nitrogen oxides.     

上海市汽车更新淘汰减排效果初步评估

选取2009年6月—2010年1月上海市汽车动态数据,讨论汽车污染物排放状况,分析汽车更新淘汰对大气环境的排放贡献影响。结果表明,上海市现行老旧车辆更新淘汰政策可以减少CO、HC、NOx、PM等污染物排放量43 565 t/a。鼓励老旧汽车淘汰更新政策对推进减排工作、改善城市大气环境有重要意义。     

Levels and composition of volatile organic compounds on commuting routes in Detroit, Michigan

Vehicle emissions can constitute a major share of ambient concentrations of many volatile organic compounds (VOCs) and other air pollutants in urban areas. Especially high concentrations may occur at curbsides, vehicle cabins, and other microenvironments. Such levels are not reflected by monitoring at fixed sites. This study reports on measurements of VOCs made from buses and cars in Detroit, MI. A total of 74 adsorbent tube samples were collected on 40 trips and analyzed by GC-MS for 77 target compounds. Three bus routes, selected to include residential, commercial and heavily industrialized areas, were sampled simultaneously on four sequential weeks during morning and afternoon rush hour periods. Nineteen compounds were regularly detected and quantified, the most prevalent of which included hexane/2-methyl pentane (15.6±5.8 μg m⁻³), toluene (10.2±7.9 μg m⁻³), m,p-xylene (6.8±4.7 μg m⁻³), benzene (4.5±3.0 μg m⁻³), 1,2,4-trimethylbenzene (4.0±2.6 μg m⁻³), o-xylene (2.2±1.6 μg m⁻³), and ethylbenzene (2.1±1.5 μg m⁻³). VOC levels in bus interiors and outdoor levels along the roadway were similar. Despite the presence of large industrial sources, route-to-route variation was small, but temporal variation was large and statistically significant. VOC compositions and trends indicate the dominance of vehicle sources over the many industrial sources in Detroit with the possible exceptions of styrene and several chlorinated VOCs. In-bus levels exceeded concentrations at fixed site monitors by a factor of 2–4. VOC concentrations in Detroit traffic are generally comparable to levels measured elsewhere in the US and Canada, but considerably lower than measured in Asia and Europe.     

移动式承压类特种设备应急平台研发

本文在搭建移动式承压类特种设备应急联动系统的背景下,重点开发移动式承压类特种设备应急平台.该平台是应急联动系统的核心控制部分,可实现危化品车辆管理、在线监测、事故分析、应急救援、统计分析、基础数据管理、系统管理等功能.应急联动系统融入“平战结合”理念,危险发生时,首先,平台从现场侦测装置自动采集数据;其次,启动事故分析和应急救援模块,必要时自动开启喷淋装置;第三,基于模型预测结果生成相应的应急救援方案;最后,发送到手持终端.该系统可以提升移动式承压类特种设备突发事件应急的及时性、科学性和有效性.     

Effects of low concentration biodiesel blends application on modern passenger cars. Part 3: Impact on PAH, nitro-PAH, and oxy-PAH emissions

This study explores the impact of five different types of methyl esters on polycyclic aromatic hydrocarbon (PAH), nitrated-PAH and oxygenated PAH emissions. The measurements were conducted on a chassis dynamometer, according to the European regulation. Each of the five different biodiesels was blended with EN590 diesel at a proportion of 10-90% v/v (10% biodiesel concentration). The vehicle was a Euro 3 compliant common-rail diesel passenger car. Emission measurements were performed over the NEDC and compared with those of the real traffic-based Artemis driving cycles. The experimental results showed that the addition of biodiesel led to some important increases in low molecular-weight PAHs (phenanthrene and anthracene) and to both increases and reductions in large PAHs which are characterised by their carcinogenic and mutagenic properties. Nitro-PAHs were found to reduce with biodiesel whereas oxy-PAH emissions presented important increases with the biodiesel blends. The impact of biodiesel source material was particularly clear on the formation of PAH compounds. It was found that most PAH emissions decreased as the average load and speed of the driving cycle increased. Cold-start conditions negatively influenced the formation of most PAH compounds. A similar trend was observed with particulate alkane emissions.     

沈阳市汽车排气检测情况及有关问题探讨

本文对沈阳市４条检车线汽车排气的检测情况做了简单介绍，并把测试数据进行了概括分析，根据实践经验提出限制汽车污染物排放的几项建议．     

The impact of off-road vehicles on a desert ecosystem

The effects of operating a 4-wheel drive truck in a 9-ha area of the Mojave Desert were evaluated. A truck was driven over the same 0.9-km track 21 times between November 1973 and May 1974. The vehicle was also driven randomly around the area (1.3 to 3.4 km) 17 times between December 1973 and May 1974.Spring densities of annual plants in ruts of the regular track (8/m²) were less than those in control areas (46–112/m²), but densities in randomly driven plots (39/m²) did not differ significantly from controls. Severity of damage to shrubs was directly related to intensity of driving in the area. About 58% of shrubs growing in the regular track sustained estimated damage ranging from 81 to 100%. In randomly driven areas only 6% of shrubs were damaged to this extent, while about 61 % sustained damage from 0 to 20%.Numbers and kinds of rodents in control and driven areas were similar before and after the experiment. More young rodents were trapped in the experimental plot than in the control area during July 1974, and this may have been promoted by basal sprouting of new growth by damaged shrubs. Estimates of numbers of side-blotched lizards indicated similar densities before, during, and after the experiment. Counts of whiptail lizards in control and experimental areas were the same after the experiment, but counts of gridiron-tailed lizards were much lower in the driven area.