自然因素对环境空气质量的影响——以新疆昌吉市为例

本文以昌吉市为例,研究并分析了温度、风、气压三种自然因素对环境空气质量的影响.结果表明,影响环境空气质量的因素非常复杂,污染天气的形成与不利的自然气象因素密切相关.     

秦皇岛市空气污染对呼吸系统疾病的影响

通过分析秦皇岛市2011—2012年每日的API值及大气PM10、 SO2、 NO2的日平均浓度变化与同时期的呼吸系统疾病日门诊人数资料,建立了时间序列分析数学模型,分析了秦皇岛市主要大气污染物与呼吸系统疾病发病的关系。发现秦皇岛市大气污染物的浓度与居民呼吸系统疾病之间存在着一定的正相关性,污染物浓度升高,居民呼吸系统疾病的就诊人数随之增加。     

气相色谱法测定室内空气中挥发性卤代烃

建立了活性炭吸附-溶剂解吸-气相色谱测定室内空气中7种挥发性卤代烃的分析方法。样品经活性炭采样管富集后,用二硫化碳解吸,Agilent HP-1色谱柱分离,使用带有电子捕获检测器的气相色谱仪测定,以保留时间定性,外标法定量。当采样体积为10 L时,方法检出限范围是0.03~0.18 g/m3,加标回收率在72%~114%之间,相对标准偏差小于15%。结果表明,该方法可以应用于室内空气中痕量挥发性卤代烃样品的检测分析。     

钢铁厂烧结烟气SCR脱硝技术应用探讨

目前烧结烟气脱硝主要采用活性炭(焦)吸附技术,投资及运行费用极高。SCR(选择性催化还原)烟气脱硝技术广泛应用于燃煤锅炉,技术成熟可靠。针对钢铁厂烧结烟气的特点,探讨了将SCR烟气脱硝技术应用于烧结烟气脱硝;通过适当的工艺优化和技术创新,烧结烟气采用SCR脱硝技术完全可行,经济适用。     

Daily Bank Erosion Rates in the Lower Yellow River Before and After Dam Construction

During the period of water impoundment and sediment detention of the Sanmenxia Reservoir, riverbank erosion processes played a key role in the channel evolution of the Lower Yellow River (LYR). However, research into bank erosion rates of the LYR has been neglected due to the lack of direct field monitoring. In this study, an indirect method is proposed to determine bank erosion rates at daily time scales by outlining a detailed calculation procedure using measured hydrological data. A total of 810 data points of daily bank erosion rates before and after the construction of Sanmenxia Dam was calculated at seven hydrometric sections along the LYR, with the corresponding values of the bank stability coefficient and the width‐to‐depth ratio also being calculated. Empirical relations were then developed to estimate the daily bank erosion rates, using these parameters at the sections. Temporal and spatial variability in daily bank erosion rates in the LYR before and after dam construction were also investigated, revealing that: (1) the bank erosion rates had a mean value of 16.7‐29.1 m/day in the braided reach, with a maximum value of 290.0 m/day, while they were relatively low in the meandering reach, with a mean value of 2.5 m/day; (2) the erosion rates before dam construction were slightly greater than those after dam construction, with the difference reaching 5‐10 m/day in the braided reach, decreasing in the transitional reach gradually, and being slight in the meandering reach.     

Persistence of Bacillus thuringiensis deposits in a hardwood forest,after aerial application of a commercial formulation at two dosage rates

Abstract

A commercial formulation of Bacillus thuringiensis Berliner var. kurstaki (BTK), Foray® 48B, was sprayed aerially over four blocks B13, B14, B15A and B15B in an oak forest in Wayne County, Pennsylvania during May 1990. B13 and B14 were sprayed at 75 billion international units (BIU) in 5.91 litres/ha and the other two at 50 BIU in 3.94 litres/ha. Oak foliage was collected at different intervals of time after treatment. Three types of bioassays were conducted against fourth instar gypsy moth larvae, viz., direct feeding of sprayed foliage, feeding on diet containing homogenized foliage, and force‐feeding of foliar extracts. Larval mortalities were converted into international units of BTK activity per unit area (IU/cm²) of foliage. Foliar extracts were also subjected to enzyme‐linked immunosorbent assay (ELISA) to determine the concentration of delta‐endotoxin protein. Regardless of the type of bioassay used, bioactivity of BTK persisted in foliage for about a week in all the blocks. The half‐life of inactivation, DT₅₀, ranged from ca 12 to 22 h. The immunoassay data indicated a shorter duration of persistence (i.e., about 2 d) of the delta‐endotoxin protein, with DT₅₀ values ranging from 10 to 15 h. Formulation ingredients present in Foray 48B played a role in the toxicity of BTK to gypsy moth larvae.     

RESEARCH: Optimizing the Mix of Strategies for Control of Vehicular Emissions

/ A number of strategies for the control of vehicular emissions are being considered by the Philippine government to address Metropolitan Manila's air quality problem. An analytical tool is needed for optimizing criteria pollutant reductions given the budgetary constraints. The simplest approach is to take costs and pollutant removals to be linear with each strategy's scale of activity, and this is readily solved as a linear programming problem. Another approach is to use a dynamic system of weights which shift with progressive improvements in pollutant emissions. The two approaches yield somewhat different results, suggesting the sensitivity of the solution to the assumed weights. The study also illustrates the importance of a sound methodology for evaluating priorities given to different air quality goals. One such methodology may involve a polling of expert panels and the public to gain insight into the relative importance given to competing emissions reduction goals. An informal polling of resource agency staff was conducted and discussed in this paper. The authors take the position that proper planning involves tracing intermediate steps to the final outcome and not just focusing on the latter.KEY WORDS: Vehicular emissions; Urban air quality; Emissions control; Optimization; Manila; Environmental systems analysis     

飞灰螯合剂中挥发性污染物的释放

采集了4个市售飞灰螯合剂样品，分析其在20，40℃下挥发性污染物的释放规律.结果表明，释放的挥发性污染物主要有甲醛、乙醛、苯、异戊醛/异丙醇、甲硫醇、乙硫醇等；其中3个螯合剂样品甲醛的释放浓度在20℃为748~1325 μg/L-螯合剂，占释放的易挥发污染物的68%~96%（质量比），在40℃为4282~6822 μg/L-螯合剂，占释放的易挥发污染物的87%~95%（质量比）.随着温度升高，释放的挥发性污染物种类变多，部分污染物浓度增加，40℃时，4个螯合剂样品释放的易挥发污染物浓度比20℃时增加了142%~444%.元素分析、拉曼光谱和热重分析结果表明，4个螯合剂的主要有效成分相似，为二硫代氨基甲酸盐类物质.因此，推测这种飞灰螯合剂在稀释和飞灰稳定化过程中，对工作人员的健康可能有潜在的危害风险，应收集释放的气体并进行处理；且在飞灰填埋过程中，可能会导致渗滤液中NH₄⁺-N等物质的浓度升高，增加渗滤液的处理难度.