Intercontinental transport of air pollution

There is an increasing interest on the intercontinental transport of air pollution among the three main emission regions at northern mid-latitudes: North America, Europe, and East Asia. Air pollutants with sufficient long lifetime can be transported from one continent to another. Observations from ground sites, aircraft and satellites have demonstrated this intercontinental-scale transport of air pollutants in the free troposphere. Numerical models have been applied to understand the pathways of the transport and the impact of intercontinental pollution transport. This paper reviews current observational evidence and modeling studies of intercontinental transport of ozone and its precursors, and the resulting impacts on air quality.     

A statistical procedure for determining the best performing air quality simulation model

Air quality simulation models have been the subject of extensive evaluations to determine their performance under a variety of environmental and meteorological conditions. While much information has been gathered, no clearly defined methodology exists for comparing the performance of two or more models. The purpose of this paper is to present a statistically oriented procedure to test if the performance of one model is superior to others using a composite performance index involving the bootstrap resampling technique.     

Advances in air pollution control for vessels in China

Vessel emissions have contributed a great deal to air quality deterioration in China. Hence,the Chinese government has promulgated a series of stringent emission regulations. It is in this context that vessel emission control technology research is in full swing. In particular,during the 13th Five-Year Plan, the air pollution control technology of vessels has greatly improved. Vessel emission control has followed two main governance routes: source emission reduction and aftertreatment technology...     

Sodar in air pollution meteorology

Information concerning atmospheric stability and turbulence is basic in studies related to air pollution meteorology. In this context a monostatic sodar has been operating at the National Physical Laboratory, New Delhi, for many years to probe the thermal structure of the lower atmosphere in real time and space.Various observed thermal structures viz. nocturnal inversion, thermal plumes, formation and break-up of inversion, orographical mixing, multilayered structures and waves etc., are the result of the different atmospheric stabilities and turbulence conditions. These structures have been studied in the light of surface measurements of wind speed and direction for organized indexing of the structural details to infer meteorological conditions concerning Pasquill stability classifications.The height of the ground-based thermal structure has been correlated with the Richardson number, Ri, for quantitative estimation of the turbulence parameter. Estimated values of Ri have been further used to determine the cross wind dispersion coefficient, σ_y. The results obtained are realistic and can be used as input parameters for air pollution modelling.     

Statistical forecast models for daily air particulate iron and lead concentrations for Madrid,Spain

Statistical models that estimate the daily concentrations of air-particulate Fe and Pb (which are linked to natural and anthropogenic sources, respectively) in a semi-urban area of Madrid, Spain, have been specified. State-space modeling, coupled with Kalman filtering, and Box-Jenkins (transfer function and ARIMA) modeling has been used. Wind speed, which is related to the atmospheric diffusion, has been selected as an exogenous variable for the state-space and transfer function models. The adaptive state-space models do not seem to perform significantly better than the transfer function models but clearly do better than ARIMA models. One-day-lagged wind s̀peed and the persistence were the most important inputs for the proposed Fe and Pb concentration models. However, the predictions of daily Fe particle concentration appears to be better than those of Pb. The performance of the adaptive state-space models suggests that this kind of modeling can be suitable for particulate matter air quality forecasting.     

突发型大气污染源位置识别反演问题的数值模拟

在突发型大气污染事件中,能否根据临时监测数据对污染源的位置进行快速识别,对于城市大气污染源的控制管理以及改善城市空气质量意义重大.为了构建突发型大气污染源位置识别的空间反演算法,本文通过分析大气应急污染监测的临时采样数据,结合污染物浓度扩散模型,随机生成污染源和计算污染物浓度的空间分布,对突发型大气污染源进行定位并与实际测量结果进行对比分析,采用蒙特卡洛模拟(Monte Carlo simulation)对相关参数进行讨论,最终构建能对突发型大气污染源进行快速估计定位的空间反演算法.研究结果表明,本文构建的空间反演算法输出的污染源坐标与实际情况相符.因此,该算法可用于突发型大气污染源位置的快速识别.     

On the memory effect of limestone for air pollution

During the last decade, there have been several reports in the literature on the “memory effect of building stones”, indicating that the stone erosion rate depends also on the environmental conditions the stone has experienced in the past. The present study checks whether this effect exists. A network of microcatchment units, exposing Massangis stone slabs to ambient atmospheric conditions, has therefore been set up througout Belgium. Runoff water fromt the stome specimens was collected on a weekly basis. The limestone slabs were switched between sites with different pollution levels, and their material loss rate trends examined. The rate of stone loss distinctly changed after the displacement, indicating an immediate adaptation of the stone to the new environment. Hence no evidence for a memory effect could be found.     

The use of biological criteria as a tool for water resource management

The status of biological criteria in state and federal water quality programs suggest that the majority of North American resource types have at least a single multimetric index developed. Large rivers, wetlands, and lakes are in the process of being studied and reference conditions are being developed but have primarily been developed for the Midwest and Northeastern United States. Biological criteria can include a variety of biological indicators ranging from multimetric indices, univariate indices, standard zoological and botanical indicators, and predictive models. The use of biological models to predict local conditions can result in a variety of spatial scales that biological criteria can address. Biological criteria will be applied as a measure of water resource condition, as biological restoration goals, for enforcement and compliance, for establishing baseline for Natural Resource Damage Assessments (NRDA), for formulating predictive models, and by the Environmental Protection Agency (EPA) for meeting the Government Performance and Results Act Goal 2b.     

Developing sediment quality criteria for heavy metal pollution in the Le An River with equilibrium partitioning approach

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城市空气污染数值预报模式系统及其应用

 介绍了城市空气污染数值预报模式系统,并利用该系统对济南市空气污染进行了预报.结果表明,该系统具有较好的预报性能;预报与实测值之间有较好的相关性;空气质量级别的预报效果更好,对SO₂、PM₁₀和NO₂ 3项污染物的级别预报准确率分别为84.6%,83.2%和94.6%,其总体级别预报准确率达到87.5%.研究结果还显示,济南市的SO₂污染已得到明显改善,机动车尾气污染相对较轻,而PM₁₀的污染比较严重,已上升为首要污染物,其来源、扩散、转化机制及其控制措施的研究是目前济南市面临的首要问题.     

Status of air pollution in Beijing

A study has been made on elements organic constituents, TSP, SO2,NO2 of atmospheric pollutants in Beijing. 17 elements, and some PAHs, e. g. B(a)P, B(b, j, k)P, and B(g, h, i)P, in airborne particles by X-ray fluorescence spectroscopy and HPLC, GC/MS, have been determined respectively. It has been shown that the elements Pb, Zn, S and Cu were more enriched in fine particles and different valence states of sulfur at various sites. It was found that the concentrations of S6+ and S2-were more than 85% and less than 15% of the total sulfur respectively. Concentrations of major PAHs and sulfur-containing compounds increased in winter and in urban area. High values for Pb and Zn in city, Fe and Mn at industrial area and Cu, Al rural sites were obtained respectively. This implies the functions of different elemental sources of various sites. Thus, elements can be from distingushed anthropogenic and natural sources.The main contribution of SO2 was found of to have same seasonal variation as the anthropogenic el     

区域复合型大气污染调控模型研究

区域复合型大气污染是我国当前面临的主要环境问题之一,为了对其开展经济、有效的调控,本研究提出了一套适用于区域复合型大气污染环境容量规划和污染调控方案优化的线性规划模型.该模型针对区域复合型大气污染特征,可以同时处理多种一次污染和二次污染因子,综合考虑污染控制技术措施对于多种污染物的治理或去除效果、采用“差距闭合法”确定环境质量控制目标并建立软边界约束条件,以提高模型结果的合理性和可行性.在综合考虑多因子环境目标、污染控制经济技术条件以及环境管理要求等多种约束条件下,寻求区域污染控制措施费用最小的控制方案.案例研究结果表明,模型合理、有效,具有较好的推广应用价值.     

Indoor air pollution by organic emissions from textile floor coverings. Climate chamber studies under dynamic conditions

The time dependence of the emission of organic compounds from a polyamide floor covering with styrene-butadiene-rubber (SBR) backing was studied in three climate chambers (0.03, 1.0 and 38 m³) at 23°C 5nd 45% RH. While volatile compounds such as toluene reach a maximum concentration in the gas phase within 1 h and decrease in concentration to less than 2% within 60 h, the concentration of less volatile compounds, such as 4-phenylcyclohexene, decreases slowly over a period of months.If the chamber is well mixed and a defined chamber loading is maintained the observed concentrations do not depend on the chamber size, the wall material and air velocity. The concentration of the observed emissions is roughly proportional to the chamber loading. Surprisingly it is not inversely proportional to the air exchange rate. Rather, at high air exchange rates mass transfer from the carpet to the gas phase is enhanced.The “decreasing source models” of Dunn and Tichenor (Atmospheric Environment22, 885–894, 1988) have been applied to the data. They allow the extrapolation of experimental data beyond the time available for measurement.The model calculations reveal the presence of sink effects. The role of the chamber walls as sinks can be determined more reliably if constant sources of an organic compound are placed into the chamber and their increase in concentration with time is compared with the theoretical predictions neglecting sink effects.     

A policy review of synergies and trade-offs in South African climate change mitigation and air pollution control strategies

Climate change mitigation and air quality management are mostly addressed separately in South African legal acts and policies. This approach is not always coherent, especially in the context of other serious issues South Africa is facing, such as poverty alleviation. Policies implemented to mitigate climate change might increase negative health affects due to unanticipated outcomes (e.g. increased local air pollution), and these indirect consequences must therefore be taken into account when devising mitigation strategies. However, greenhouse gas mitigation policies can also have co-benefits and positive impacts on local air pollution. An evidence-based approach that takes into account greenhouse gas emissions, ambient air pollutants, economic factors (affordability, cost optimisation), social factors (poverty alleviations, public health benefits), and political acceptability is needed tackle these challenges. A proposal is made that use of an integrated climate/air pollution techno-economic optimising model, such as the Greenhouse Gas and Air Pollution Synergies (GAINS) model, may provide a rational decision support tool to guide policy makers into effective strategies for combined Climate Change and Air Quality mitigation measures.     

Overview of current regional and local scale air quality modelling practices: Assessment and planning tools in the EU

The 2008 European Air Quality Directive (AQD) (2008/50/EC) encourages the use of models in combination with monitoring in a range of applications. It also requires Member States to design appropriate air quality plans for zones where the air quality does not comply with the AQD limit values. In order to cope with these various elements, a wide range of different modeling methods have been developed and applied by EU Member States in the last decade to assess the effects of local and regional emission abatement policy options on air quality and human health. However, an overall review of the methodologies that are used in different countries to compile local and regional air quality plans has not been performed so far. Such a review has been the objective of the APPRAISAL EU FP7 project with the main goal to identify methodologies and their limitations and to propose possible key areas to be addressed by research and innovation on the basis of this review. To fulfill these objectives, a structured online database of methodologies has been developed in collaboration with experts involved in the design of air quality plans (AQP). The current work relies on the APPRAISAL database which currently totals 59 contributions from 13 Member States. In this paper we summarize the outcome of the APPRAISAL project with respect to the review of current Integrated Assessment Modeling practices.     

Improving the prediction of air pollution peak episodes generated by urban transport networks

This paper illustrates the early results of ongoing research developing novel methods to analyse and simulate the relationship between trasport-related air pollutant concentrations and easily accessible explanatory variables. The final scope is to integrate the new models in traditional traffic management support systems for a sustainable mobility of road vehicles in urban areas.This first stage concerns the relationship between the hourly mean concentration of nitrogen dioxide (NO₂) and explanatory factors reflecting the NO₂ mean level one hour back, along with traffic and weather conditions. Particular attention is given to the prediction of pollution peaks, defined as exceedances of normative concentration limits. Two model frameworks are explored: the Artificial Neural Network approach and the ARIMAX model. Furthermore, the benefit of a synergic use of both models for air quality forecasting is investigated.The analysis of findings points out that the prediction of extreme concentrations is best performed by integrating the two models into an ensemble. The neural network is outperformed by the ARIMAX model in foreseeing peaks, but gives a more realistic representation of the concentration's dependency upon wind characteristics. So, the Neural Network can be exploited to highlight the involved functional forms and improve the ARIMAX model specification. In the end, the study shows that the ability to forecast exceedances of legal pollution limits can be enhanced by requiring traffic management actions when the predicted concentration exceeds a lower threshold than the normative one.     

美国水质基准技术分析与我国相关基准的构建

介绍了以保护自然生态系统中水生生物为主要目标的美国水质基准技术指南. “指南"在研究个体水平的动、植物毒性数据的基础上进行数理分析,得出数值化的环境水质基准,并给出了相关计算模式和技术路线. 指出基准构建在种群、群落和生态系统水平等的毒性试验数据应用方面还有待发展完善,另外,“指南”中选择的试验生物也不适用于我国水质基准的制订研究. 以辽河流域为例,对我国水质基准的研究提出如下建议:①试验生物应选择有区域代表性的特征物种,我国基本可以采用US EPA规定的物种选用原则,但须包括鲤科鱼类;②关注种群和群落水平的毒性数据;③基于当地物种和水质状况或水生态功能分区信息制订区域水质基准.      

Multiobjective air pollution monitoring network design

The methodologies currently available to optimize the locations of air pollutant monitoring stations typically include a single pollutant and a single objective. In this paper, multiple objective functions are introduced that provide performance measures describing the spatial coverage of the network and its ability to detect violations of standards for multiple pollutants. An additional objective regarding the effect of data validity in the design is also considered. The objective functions are cast in a manner that permits considerable flexibility in the model formulation. The numerical difficulties associated with the formulation are discussed as are extensions of the basic framework. The basic model and its extensions have been applied to the design of a monitoring network for Tarragona, Spain.     

Accurate prediction of air quality response to emissions for effective control policy design

Designing effective control policy requires accurate quantification of the relationship between the ambient concentrations of O₃and PM_2.5and the emissions of their precursors.However,the challenge is that precursor reduction does not necessarily lead to decreases in the concentrations of O₃and PM_2.5,which are formed by multiple precursors under complex physical and chemical processes;this calls for the development of advanced model technologies to prov...