Analysis of the Trend and Seasonal Cycle of Carbon Monoxide Concentrations in an Urban Area (4 pp)

Background, Aim and Scope Air quality is an field of major concern in large cities. This problem has led administrations to introduce plans and regulations to reduce pollutant emissions. The analysis of variations in the concentration of pollutants is useful when evaluating the effectiveness of these plans. However, such an analysis cannot be undertaken using standard statistical techniques, due to the fact that concentrations of atmospheric pollutants often exhibit a lack of normality and are autocorrelated. On the other hand, if long-term trends of any pollutant’s emissions are to be detected, meteorological effects must be removed from the time series analysed, due to their strong masking effects. Materials and Methods The application of statistical methods to analyse temporal variations is illustrated using monthly carbon monoxide (CO) concentrations observed at an urban site. The sampling site is located at a street intersection in central Valencia (Spain) with a high traffic density. Valencia is the third largest city in Spain. It is a typical Mediterranean city in terms of its urban structure and climatology. The sampling site started operation in January 1994 and monitored CO ground level concentrations until February 2002. Its geographic coordinates are W0°22′52″ N39°28′05″ and its altitude is 11 m. Two nonparametric trend tests are applied. One of these is robust against serial correlation with regards to the false rejection rate, when observations have a strong persistence or when the sample size per month is small. A nonparametric analysis of the homogeneity of trends between seasons is also discussed. A multiple linear regression model is used with the transformed data, including the effect of meteorological variables. The method of generalized least squares is applied to estimate the model parameters to take into account the serial dependence of the residuals of this model. This study also assesses temporal changes using the Kolmogorov-Zurbenko (KZ) filter. The KZ filter has been shown to be an effective way to remove the influence of meteorological conditions on O₃ and PM to examine underlying trends. Results The nonparametric tests indicate a decreasing, significant trend in the sampled site. The application of the linear model yields a significant decrease every twelve months of 15.8% for the average monthly CO concentration. The 95% confidence interval for the trend ranges from 13.9% to 17.7%. The seasonal cycle also provides significant results. There are no differences in trends throughout the months. The percentage of CO variance explained by the linear model is 90.3%. The KZ filter separates out long, short-term and seasonal variations in the CO series. The estimated, significant, long-term trend every year results in 10.3% with this method. The 95% confidence interval ranges from 8.8% to 11.9%. This approach explains 89.9% of the CO temporal variations. Discussion The differences between the linear model and KZ filter trend estimations are due to the fact that the KZ filter performs the analysis on the smoothed data rather than the original data. In the KZ filter trend estimation, the effect of meteorological conditions has been removed. The CO short-term componentis attributable to weather and short-term fluctuations in emissions. There is a significant seasonal cycle. This component is a result of changes in the traffic, the yearly meteorological cycle and the interactions between these two factors. There are peaks during the autumn and winter months, which have more traffic density in the sampled site. There is a minimum during the month of August, reflecting the very low level of vehicle emissions which is a direct consequence of the holiday period. Conclusions The significant, decreasing trend implies to a certain extent that the urban environment in the area is improving. This trend results from changes in overall emissions, pollutant transport, climate, policy and economics. It is also due to the effect of introducing reformulated gasoline. The additives enable vehicles to burn fuel with a higher air/fuel ratio, thereby lowering the emission of CO. The KZ filter has been the most effective method to separate the CO series components and to obtain an estimate of the long-term trend due to changes in emissions, removing the effect of meteorological conditions. Recommendations and Perspectives Air quality managers and policy-makers must understand the link between climate and pollutants to select optimal pollutant reduction strategies and avoid exceeding emission directives. This paper analyses eight years of ambient CO data at a site with a high traffic density, and provides results that are useful for decision-making. The assessment of long-term changes in air pollutants to evaluate reduction strategies has to be done while taking into account meteorological variability     

An introductory note on the environmental economics of the circular economy

This paper provides an introduction to some of the fundamental principles and approaches in environmental economics which are of significance to achieving an integrated sustainability science. The concept of a circular economy, introduced by the late David Pearce in 1990, addresses the interlinkages of the four economic functions of the environment. The environment not only provides amenity values, in addition to being a resource base and a sink for economic activities, it is also a fundamental life-support system. Environmental economists have suggested that, taking these four functions as an analytical starting point, unpriced or underpriced services should be internalised in the economy. In Europe significant advances have been achieved in the pricing of externalities by means of truly interdisciplinary analysis which accounts in detail for the environmental consequences. The monetary estimates reached as a result of such interdisciplinary research are gradually being applied to the economic analysis of environmental policy priorities. Although such figures provide only a partial and incomplete picture of the environmental costs at stake, they support and inform the analysis of the virtues of a circular economy for individual resources as well as for sustainability as a future trajectory.     

Dynamics and Causation of Environmental Equity, Locally Unwanted Land Uses, and Neighborhood Changes

/ Why are some environmental risks distributed disproportionately in the neighborhoods of the minorities and the poor? A hypothesis was proposed in a recent study that market dynamics contributed to the current environmental inequity. That is, locally unwanted land uses (LULUs) make the host communities home to more poor people and people of color. This hypothesis was allegedly supported by a Houston case study, whereby its author analyzed the postsiting changes of the socioeconomic characteristics of the neighborhoods surrounding solid waste facilities. I argue that such an analysis of postsiting changes alone is insufficient to test the causation hypothesis. Instead, I propose a conceptual framework for analysis of environmental equity dynamics and causation. I suggest that the presiting neighborhood dynamics and the characteristics of control neighborhoods be analyzed as the first test for the causation hypothesis. Furthermore, I present theories of neighborhood change and then examine alternative hypotheses that these theories offer for explaining neighborhood changes and for the roles of LULUs in neighborhood changes. These alternative hypotheses should be examined when analyzing the relationship between LULUs and neighborhood changes in a metropolitan area. Using this framework of analysis, I revisited the Houston case. First, I found no evidence that provided support for the hypothesis that the presence of LULUs made the neighborhoods home to more blacks and poor people, contrary to the conclusion made by the previous study. Second, I examined alternative hypotheses for explaining neighborhood changes-invasion-succession, other push forces, and neighborhood life-cycle; the former two might offer better explanation.KEY WORDS: Environmental equity and justice; Locally unwanted lane uses; Siting; Market dynamics; Invasion-succession; Neighborhood changes     

酸性法测定高锰酸盐指数加热时间的选择

酸性法测定高锰酸盐指数，会因实验条件的差异产生不同的结果。对不同加热时间，加热方式等因素进行了试验，结果表明加热时间以水浴加热沸腾３０ｍｉｎ或电炉直接加热８ｍｉｎ为宜。     

大连声环境质量的灰色预测研究

根据1999年～2003年大连市区声环境质量的监测数据，采用两次残差修正GM（1，1）对2010年前声环境质量进行预测结果表明，修正后模型均为一级模型，进行中、短期预测精度高。预测结果可为城市噪声污染防治提供科学的依据。     

参窝水库水体自净能力及水质变化规律研究

根据参窝水库近几年的水质监测资料，对参窝水库的水体自净能力及水质变化规律进行了较深入的研究、计算出主要污染物在参窝水库的自净率，分析了参窝水库水质变化规律，为参窝水库的水污染防治提供了科学的依据。     

乡镇企业环境保护工作初探

近年来，乡镇企业蓬勃发展的趋势要求我们必须重视其环境保护工作．笔者通过联系当地的实际情况力图阐明自己对于如何搞好乡镇企业环境保护工作的一些观点。     

Environmental principles applicable to supply chains design and operation

In this paper we deal with the problem of identifying environmental principles for the design and operation of supply chains. The operations that are included in supply chains are briefly described along with the approaches that are applied in order to improve their environmental performance. A background of environmental principles for achieving eco-efficiency and building of environmentally friendly organizational systems is presented and emphasis is put on the application of such principles “from cradle to grave”. Then, environmental principles applicable to particular objects of logistics networks planning are identified and commented upon. In addition, selective case studies from the literature, which show the applicability of the formulated principles and their relevance to practice, are discussed. The paper concludes with some remarks regarding the benefits for companies and societies, in general, that occur as a result of the application of the formulated principles.     

世行贷款项目环境管理

介绍了世行贷款项目各阶段环境管理的具体内容和特殊问题，并提出面临难题。     

论环境科技发展对国际贸易的影响

文章通过对世界环境发展形势以及环境科技发展特点的剖析，结合国内外实例深入探讨并阐述了环境科技发展对国际贸易关系的重大影响。文章认为国际贸易格局将迅速发生变革，提出了我国应采取的法规、政策、标准、技术等方面的对策。