A Preliminary Look at Source-Receptor Relationships in the Texas-Mexico Border Area

ABSTRACT

Several factors have recently caused visibility impairment at Big Bend National Park, TX, to be of interest. Analyses of historical data collected there have shown that visibility is poorer and fine particle concentrations are higher at Big Bend than at other monitored Class I areas in the western United States. In addition, air masses frequently arrive there after crossing Mexico, where emissions are not well known. During September and October 1996, a field study was undertaken to begin examining the aerosol, visibility, and meteorology on both sides of the border. Results indicate that, during the study, the largest fractions of fine mass and light extinction at Big Bend were due to sulfates and the trace elements most closely associated with sulfate particles were Na and Se. Based on back trajectory modeling and the spatial, temporal, and inter-species relationships in the fine particle concentrations measured during the study, sulfates arrived at the park from both Mexico and the United States. Se was higher in Texas than in Northern Mexico, while V, Pb, Zn, Ni, and Mn were on average much higher in Mexico.     

城市生活垃圾压缩站环境污染研究

通过对垃圾压缩站内生活垃圾进行采样分析、压实试验和环境污染检测，得出了城市生活垃圾压实密度和施加压力的关系曲线，确定了对垃圾压实的合适压力范围为0．1～0．2MPa；垃圾压缩站环境污染严重，垃圾压缩污水量为10-50kg／t，其中BOD5和COD平均分别超标111倍和486倍；环境噪音只有50m以外才能达到居民区环境质量二级标准（60dB（A））的噪音要求；产生的臭气在较低风速下一般扩散25m时污染达到最大，NH3、H2S分别可以达到0．011、0．0046mg／m^3，这个值占容许浓度的55％和46％。     

Performance Audits of EPA Protocol Gases and Inspection and Maintenance Calibration Gases

Air pollution abatement policies must be based on quantitative information on current and future emissions of pollutants. As emission projections uncertainties are inevitable and traditional statistical treatments of uncertainty are highly time/resources consuming, a simplified methodology for nonstatistical uncertainty estimation based on sensitivity analysis is presented in this work. The methodology was applied to the “with measures” scenario for Spain, concretely over the 12 highest emitting sectors regarding greenhouse gas and air pollutants emissions. Examples of methodology application for two important sectors (power plants, and agriculture and livestock) are shown and explained in depth. Uncertainty bands were obtained up to 2020 by modifying the driving factors of the 12 selected sectors and the methodology was tested against a recomputed emission trend in a low economic-growth perspective and official figures for 2010, showing a very good performance.

Implications:?A solid understanding and quantification of uncertainties related to atmospheric emission inventories and projections provide useful information for policy negotiations. However, as many of those uncertainties are irreducible, there is an interest on how they could be managed in order to derive robust policy conclusions. Taking this into account, a method developed to use sensitivity analysis as a source of information to derive nonstatistical uncertainty bands for emission projections is presented and applied to Spain. This method simplifies uncertainty assessment and allows other countries to take advantage of their sensitivity analyses.     

Evaluation of Selected Gaseous Halocarbons for Use in source Test Performance Audits

A repository of 38 gaseous organic compounds in compressed gas cylinders has been established by EPA. This repository was established to provide standards for source test performance audits, that is, quantitative quality assurance tests. Among these compounds are ten halogenated organic species, which are the focus of this paper.

Stability studies of all ten compounds have been performed to determine the feasibility of using them as performance audit standards. Results indicate that all of the halocarbons tested are adequately stable to be used as reliable audit standards.

Subsequent to completion of stability studies, four of the ten halocarbons were used in source test performance audits. Results are available at this time for two of the four compounds; the results show agreement within 10% of the concentrations previously established by Research Triangle Institute.     

农业的环境保护及对策探讨

农业环境是社会环境的重大组成部分，保护好农业环境是当前一个非常重大和十分紧迫的任务。文章分析了农业环境保护中存在的问题，并提出有关对策。     

A Practical Relationship Between Government and Industry

The science of air pollution control is making significant advances and a practical working arrangement between all levels of government and industry must be achieved. Lawmakers, scientists, and industry must work side by side in combatting air pollution; there is no other approach that will give the problem the attention it deserves. How this might be accomplished is the subject of this article.     

A Multivariate Baltic Sea Environmental Index

Since 2001/2002, the correlation between North Atlantic Oscillation index and biological variables in the North Sea and Baltic Sea fails, which might be addressed to a global climate regime shift. To understand inter-annual and inter-decadal variability in environmental variables, a new multivariate index for the Baltic Sea is developed and presented here. The multivariate Baltic Sea Environmental (BSE) index is defined as the 1st principal component score of four z-transformed time series: the Arctic Oscillation index, the salinity between 120 and 200 m in the Gotland Sea, the integrated river runoff of all rivers draining into the Baltic Sea, and the relative vorticity of geostrophic wind over the Baltic Sea area. A statistical downscaling technique has been applied to project different climate indices to the sea surface temperature in the Gotland, to the Landsort gauge, and the sea ice extent. The new BSE index shows a better performance than all other climate indices and is equivalent to the Chen index for physical properties. An application of the new index to zooplankton time series from the central Baltic Sea (Latvian EEZ) shows an excellent skill in potential predictability of environmental time series.     

环境预防学

环境预防学是一门研究未来环境变化趋势和采取相应对策的科学。广义的环境预防学包括自然灾害预防学和由人类引起的环境污染或生态破坏预防学，狭义的环境预防学仅指由人类引起的环境污染或生态破坏预防学。环境预防是人类可持续发展的基础，环境预防学研究生态环境预防、环境污染预防、化学品环境危害的预防和环境预防体系等内容。环境预防学的研究涉及到很多学科，是一门新兴的交叉边缘学科。环境预防学可以对环境危害防患于未然，对人类可持续发展具有重大的意义。     

基层环境监测站环境质量综合分析中存在的问题及对策

从环境监测为环境管理服务的职能入手,系统分析了基层环境监测站的环境质量综合分析工作现状,针对实际工作中存在的问题,提出了提高环境质量综合分析水平的对策建议。     

Dry Deposition of Ammonia at Environmental Concentrations on Selected Plant Species

The deposition velocity of NH₃ on six plant species at environmental concentrations has been studied in a dynamic plant gas exchange reactor. The total resistance to the transport of NH₃ was studied. The aerodynamic resistance was determined directly by NH₃ gas absorption in aqueous solutions at environmental concentrations in a two-phase gradientless reactor modeling the transfer processes through the stomata in a leaf. The concentration of NH₃ in the gas phase ranged from 50 to 1000 ppb and the temperature varied from 25 to 30°C. The results for the deposition velocity for NH₃, during the day, varied from 0.3 to 1.3 cm/s. The deposition velocities at night were about one order of magnitude smaller. These results are compared with estimates from the Frdssling equation which consistently yields higher values of the same order of magnitude. To determine accurate atmospheric transport models or global budget models, a variable deposition velocity should be used to account for the diurnal and seasonal variations in the surface resistance.     

Evaluation of Parts-per-billion Organic Cylinder Gases for Use as Audits During Hazardous Waste Trial Burn Tests

A repository of 14 gaseous organic compounds at parts-per-billion levels (7-430 ppb) in compressed gas cylinders has been established by the Environmental Protection Agency. This repository was established to provide audit materials for use in conducting performance audits to assess the accuracy and precision of principal organic hazardous constituent (POHC) measurements, especially those performed during hazardous waste trial burn tests. Five- and nine-component mixtures In a balance gas of nitrogen were prepared in aluminum cylinders for use in the performance audit program. The five-component mixtures contain carbon tetrachloride, chloroform, perchloroethylene, vinyl chloride, and benzene. The ninecomponent mixtures contain trichloroethylene, 1,2-dichloroethane, 1,2-dibromoethane, acetonitrile, trichlorofjuoromethane, dichlorodifluoromethane, bromomethane, methyl ethyl ketone and 1,1,1-trichloroethane.

Studies of all 14 gaseous organic compounds were performed to determine the stability of the compounds and the feasibility of using them in performance audits. Results indicate that ail of the 14 compounds were adequately stable to be used as reliable audit materials. Also, the estimation of specific uncertainties associated with the analysis of these audit materials and how those uncertainties are used to assign a total uncertainty to the final analyte concentration for 14 organics Is described.

Subsequent to completion of the stability studies, several performance audits were conducted using the repository gases to assess the accuracy and precision of the volatile organic sampling train (VOST) and bag measurement methods. The audit results indicate that laboratories can use these methods to analyze POHC with accuracy usually to within ± 50 percent of the audit concentrations.     

A Narrative Policy Approach to Environmental Conservation

Due to the urgency and seriousness of the loss of biological diversity, scientists from across a range of disciplines are urged to increase the salience and use of their research by policy-makers. Increased policy nuance is needed to address the science–policy gap and overcome divergent views of separate research and policy worlds, a view still relatively common among conservation scientists. Research impact considerations should recognize that policy uptake is dependent on contextual variables operating in the policy sphere. We provide a novel adaptation of existing policy approaches to evidence impact that accounts for non-evidentiary “societal” influences on decision-making. We highlight recent analytical tools from political science that account for the use of evidence by policy-makers. Using the United Kingdom’s recent embrace of the ecosystem approach to environmental management, we advocate analyzing evidence research impact through a narrative lens that accounts for the credibility, legitimacy, and relevance of science for policy.     

A Comparative Study of Environmental Tobacco Smoke Particulate Mass Measurements in an Environmental Chamber

Particulate mass concentration measurements have been made on environmental tobacco smoke (ETS) for the purpose of assessing the relative accuracy of several measurement procedures. ETS over a range of concentrations was generated in an environmental chamber by three methods. Mass concentration was measured by a gravimetric/spectrophotometric collection procedure, piezoelectric particle mass monitors, two nephelometry-based mass monitors, and a particle counting and sizing system. Two-hour average mass concentrations were determined by each method for concentrations ranging from very low levels up to those achieved by smoking one entire cigarette in the chamber. Statistical comparisons were made among procedures employing the gravimetric filter measurement as the basis for comparison. One nephelometry-based procedure gave significantly higher and the other significantly lower values than the filter determination. In one case, a correction for the difference between the particle mass density of the calibrating aerosol and that of ETS brought the nephelometry-based procedure into reasonable agreement with the filter measurement, while for the other, the correction did not resolve the discrepancy between methods. Statistically significant differences between the responses of two supposedly identical piezoelectric mass monitors were found, as was some slight dependence of the nephelometry- based procedures on method of ETS generation. In summary, the results indicate that significant errors can be expected if the instruments studied are used “off the shelf,” even for ETS generated under controlled laboratory conditions. Caution should be employed in field measurements where numerous sources and types of particulate matter can be encountered.     

机械加工业清洁生产的一则技改实例

一家机械加工厂采用先进的工艺和设备代替落后的工艺和设备，并且撤消了一些工序和对生产车间进行了重新布局，不仅提高了工作效率，而且减少了环境污染，促进了清洁生产，对此，从废水，废气，噪声和废渣四个方面进行了详细评述。     

Environmental copper: Behaviour when involved in physical adsorption at several interfaces

From a literature-based assessment of the current knowledge about both the toxic or salutary properties of copper, this study focused on the determination, at 25 °C, of the interfacial properties of CuCl_2, either alone or in mixture with carbofuran used, here, as a model of organics and/or pesticide. The interfaces under study were: i) the air/solution interface and ii) the silica/solution interface. The former is considered as a path for volatilization, whereas the latter permits a modelling of physical adsorption upon solids, which is the first and unavoidable step in any adsorption process. One should note that it can also mimic adsorption on some sandy soils. Coadsorption was clearly identified as implicated in an enhancement of the surface content of both solutes at both interfaces. However, at the two interfaces under study, the way the surface became structured led to opposite adsorption mechanisms for the organic compounds and the salt. A rough theory about ionic adsorption is also proposed.     

Environmental distribution of uranium and other trace elements at selected Kosovo sites

This paper reports the results of a study using lichens as biomonitors to investigate the environmental distribution of uranium and other trace elements at selected Kosovo sites. The results suggested that the use of depleted uranium (DU) ammunitions in Kosovo did not cause a diffuse environmental contamination in such a way to have caused a detectable U enrichment in lichens. Also isotopic (235)U/(238)U measurements did not indicate the presence of DU particles in lichens. The present results also provided no indication of intense environmental contamination by the other trace elements analyzed, with the exception of Kosovska Mitrovica, where a diffuse environmental contamination by several heavy elements such as Pb, Zn, As and Cd was found.     

A Framework for Risk Characterization of Environmental Pollutants

Risk characterization is defined by both the U.S. National Academy of Sciences and the U.S. EPA as the estimation of human health risk due to harmful (i.e., toxic or carcinogenic) substances or organisms. Risk characterization studies are accomplished by integrating quantitative exposure estimates and dose-response relationships with the qualitative results of hazard identification.

A Risk Characterization Framework has been developed to encourage a systematic approach for analysis and presentation of risk estimates. This methodology subdivides the four common components of the risk assessment process into ten elements. Each of these elements is based on a term in a predictive risk equation. The equation allows independent computations of exposure, dose, lifetime individual risk, and risk to affected populations. All key assumptions in the predictive risk equation can be explicitly shown. This is important to understand the basis and inherent uncertainties of the risk estimation process.

The systematic treatment of each of the ten elements in this framework aids in the difficult job of comparing risk estimates by different researchers using different methodologies. The Risk Characterization Framework has been applied to various indoor and outdoor air pollutants of a carcinogenic nature. With further development, it also promises to be applicable to noncarcinogenic effects.