Determination of the effective density and fractal dimension of PM emissions from an aircraft auxiliary power unit

Gas turbine particulate matter (PM) emissions contribute to air quality degradation and are dangerous to both human health and the environment. Currently, PM mass concentrations determined from gravimetric measurements are the default parameter for gas turbine emissions compliance with PM regulations. The measurement of particle size however, is of significant interest due to its specific effects on health and climate science. The mass concentration can be determined from the number-size distribution measurement but requires the experimental evaluation of effective density of a number of particles to establish the power-law relationship. In this study, the effective density of PM emissions from an aircraft Auxiliary Power Unit (APU) with petroleum diesel, conventional aviation fuel (Jet A-1) and a multicomponent surrogate fuel (Banner NP 1014) as combusting fuels have been compared. An experimental configuration consisting of a Differential Mobility Analyzer, a Centrifugal Particle Mass Analyzer and a Condensation Particle Counter (DMA-CPMA-CPC) was deployed for this purpose. Overall, a decrease in the effective density (220–1900 km? 3) with an increase in the particle size was observed and found to depend on the engine operating condition and the type of fuel undergoing combustion. There was a change in the trend of the effective densities between the PM emissions generated from the fuels burnt and the engine operating conditions with increasing particle size.     

东北地区能源消费碳排放时空演变特征及其驱动机制

运用探索性空间分析、冷热点分析、标准差椭圆分析和地理加权回归分析等地学方法,研究了我国东北地区2005—2014年间能源消费碳排放的时空演化特征及其驱动机制.结果表明:①东北三省的能源消费碳排放量从高到低分别为辽宁省、黑龙江省、吉林省,2014年碳排放量分别达到20266、9914、6411万t;②东北三省能源消费碳排放量呈比较显著的全局空间正相关特征,在统计学上显著性检验存在多个冷、热点,其中,热点区主要集中在辽宁省的大连市、沈阳市、本溪市和辽阳市,吉林省的吉林市,以及黑龙江省的大庆市和鸡西市,冷点区主要集中在黑龙江省的大兴安岭市、黑河市、佳木斯市和伊春市;③在省级尺度上东北三省碳排放重心在2005—2014年间呈往东偏移的趋势,在市级尺度上辽宁省和吉林省碳排放重心往西偏移,而黑龙江省碳排放重心则往南偏移;④在省级尺度上,能源消费碳排放主轴方向为"西南-东北",但有往北旋转的趋势,黑龙江省能源消费碳排放主轴呈现往北旋转的趋势,辽宁省和吉林省的能源消费碳排放主轴方向则呈往东旋转的趋势;⑤东北地区影响能源消费碳排放量的主要驱动因素的影响程度排序为:人均GDP产业结构总人口数城市化率老龄化.     

公交车基于不同燃油的实际道路排放性与燃油经济性

使用便携式车载排放测试系统测试了2辆国VI公交车和2辆国III公交车燃用不同燃料的实际道路排放特性和经济性.结果表明,相比于燃用京VI车用柴油,国VI公交车燃用B5生物柴油(柴油中掺混5%生物柴油)的CO比排放降低了33.1%,NO_x比排放增加了15.6%,颗粒物数量(PN)比排放降低了13.1%.4辆公交车燃用B5生物柴油的CO排放因子较京VI车用柴油平均降低了29.5%,NO_x排放因子增加了12.7%,PN排放因子降低了9.1%.通过对CO_2的分析发现,燃用B5生物柴油的排放因子较燃用京VI车用柴油增加了11.3%,运用碳平衡计算方法计算油耗,并考虑燃油密度的影响,结果发现,燃用B5生物柴油的百公里油耗较燃用京VI车用柴油增加了11.51%,相差较大,后续需深入研究油品热值等其他理化指标对燃油经济性的影响.     

黄河流域夏季水质量评价及管理对策

为了有效保护黄河水资源,促进黄河流域绿色发展,本研究在黄河流域上、中、下游贵德、兰州、三门峡和东营地点分别采样,分析p H、溶解氧、固体悬浮物、氨氮、硝态氮、总氮、亚硝态氮、总有机碳、总无机碳、总碳、总磷、化学需氧量、五日生化需氧量、粪大肠菌群、挥发酚含量变化趋势,并进行水质综合评价。结果发现:(1)固体悬浮物变化呈现东营兰州三门峡贵德;(2)氨氮、硝态氮、总氮、总有机碳、总无机碳、总碳、总磷、化学需氧量、五日生化需氧量、粪大肠菌群变化趋势依次为三门峡兰州东营贵德;(3)亚硝态氮和挥发酚含量变化趋势为兰州三门峡东营贵德;(4)综合水质评价结果为贵德水质好于东营,东营水质好于兰州,兰州好于三门峡。研究表明邻近城市和大型支流汇入点下游河段是黄河氮污染的主要来源,流域各省各级政府领导,要认真学习习总书记提出的"绿水青山就是金山银山"的生态思想,要入脑入心,严格科学减排,"一定要把黄河的事情办好"。     

Optimal pollution permit endowments in markets with endogenous emissions

In a permit market with endogenous emissions, both firms and citizens purchase permits. Presented here are static and dynamic models of pollution permit markets with endogenous emissions. The optimal permit endowments are characterized when the regulator faces uncertainty about damages and uncertainty about the severity of the citizens’ collective action problem. Due to the possibility of learning over time, the regulator issues a larger number of permits in the first period of the dynamic model than in the static model.     

Spider webs as environmental indicators

Analysis of spider webs from limestone arches in New South Wales, Australia showed levels of lead and zinc to be several times higher at Jenolan Caves than reference sites at Abercrombie and Wombeyan Caves. The high concentrations at Jenolan were attributed to emissions from motor vehicles that travel through the arch. Analysis of water-soluble ions in webs from Jenolan and Abercrombie Caves showed large differences between the sites, which could be explained by differences in the geology and biology of the cave environments. Spider webs proved useful indicators of environmental chemistry and undoubtedly have applications beyond the cave environments studied here.     

Do Hydroelectric Dams Mitigate Global Warming? The Case of Brazil's CuruÁ-una Dam

Hydroelectric dams in tropical forest areas emit greenhouse gases, as illustrated by the Curuá-Una Dam in the Amazonian portion of Brazil. Emissions include carbon dioxide from decay of the above-water portions of trees that are left standing in the reservoir and methane from soft vegetation that decays under anaerobic conditions on the bottom of the reservoir, especially macrophytes (water weeds) and vegetation that grows in the drawdown zone and is flooded when the reservoir water level rises. Some methane is released from the reservoir surface through bubbling and diffusion, but larger amounts are released from water passing through the turbines and spillway. Methane concentration in the water increases with depth, and the turbines and spillway draw water from sufficient depth to have substantial methane content. In 1990 (13 years after filling), the Curuá-Una Dam emitted 3.6 times more greenhouse gases than would have been emitted by generating the same amount of electricity from oil.     

采用SCR技术降低车用柴油机的NOx排放

NOx是车用柴油机排气中的主要有害排放物，机外措施是控制柴油机排放的有效措施，是柴油机排放控制的关键技术。文中重点介绍了降低车用柴油机NOx排放的机外措施之一选择催化还原(SCR)技术。     

Uncertainty analysis of emission estimates in the RAINS integrated assessment model

Uncertainty is a critical issue for all models that attempt to quantify the necessary emission reductions that are required to meet environmental quality targets. This paper discusses a methodology specifically developed to analyse the uncertainties in the emission estimates with the regional air pollution information and simulation (RAINS) integrated assessment model, considering the uncertainties in the model parameters themselves. Overall, it was found that a typical range of uncertainties for modeled national emissions of sulfur dioxide, nitrogen oxides and ammonia in Europe lies between 10 and 30%. In general, the uncertainties are strongly dependent on the potential for error compensation. This compensation potential is larger (and uncertainties are smaller) if calculated emissions are composed of a larger number of equal-sized source categories, where the errors in input parameters are not correlated with each other. Thus, estimates of the national total emissions are generally more certain than estimates of sectoral emissions. A sensitivity analysis with respect to the uncertainty in input parameters showed that the actual uncertainties are critically influenced by the specific situation (pollutant, year, country). However, the emission factor is an important contributor to the uncertainty in estimates of historical emissions, while uncertainty in the activity data dominates the future estimates.     

Waste management modeling by MARKAL model: A case study for Basilicata Region

Air pollution is one of the most pressing environmental problems which affects likewise urban, industrial and rural areas. Environmental planners, regulators and decision makers need reliable, scientifically based tools to find out strategies for controlling air pollution in a cost-effective way, taking into account the whole productive system. In this framework the basic elements of energy-environmental planning have to be extended to include also waste processing technologies amongst the usually considered pollution sources. Bottom-up optimizing models, based on linear programming techniques and customized for specific cases, represent a powerful tool in energy-environmental management. This paper focuses on the integrated modeling of material flows and energy system performed on a local scale case study (Basilicata Region, Southern Italy) using the linear programming model IEA-MARKAL. We have evaluated the feasibility of the model in representing the waste management system to estimate the environmental impact of the waste processing technologies in the context of the whole productive system. A sensitivity analysis has been carried out to emphasize the connections between tariffs, waste disposal technologies assessment and atmospheric emissions. This revised version was published online in July 2006 with corrections to the Cover Date.