珠三角地区大气中HCFC-22的浓度观测和变化趋势初步研究

通过罐采样和预浓缩-色谱/质谱方法,对珠三角地区广州城区和鼎湖山大气中HCFC-22进行了初步的观测和分析.结果表明,2005年广州城区HCFC-22年平均体积分数达到(479.5±241.4)×10-12,鼎湖山仅为(244.4±51.3)×10-12.广州城区大气HCFC-22日变化幅度夏秋季节相对较大,而鼎湖山日变化不明显;广州城区大气HCFC-22的体积分数夏秋季节高于冬春季节,鼎湖山则相反.与城区HCFC-22排放的季节性有关,夏秋季节广州城区与鼎湖山HCFC-22体积分数差别很大,冬春季节则比较接近.初步研究结果表明,广州城区和鼎湖山大气HCFC-22的体积分数呈现快速增长趋势,年增长率分别达到6.57%和7.28%,约为一些全球基准观测站(NOAA/CMDL)的1.9～2.8倍.     

Atmospheric composition change – global and regional air quality

Air quality transcends all scales with in the atmosphere from the local to the global with handovers and feedbacks at each scale interaction. Air quality has manifold effects on health, ecosystems, heritage and climate. In this review the state of scientific understanding in relation to global and regional air quality is outlined. The review discusses air quality, in terms of emissions, processing and transport of trace gases and aerosols. New insights into the characterization of both natural and anthropogenic emissions are reviewed looking at both natural (e.g. dust and lightning) as well as plant emissions. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. In terms of chemical processing the major air quality elements of ozone, non-methane hydrocarbons, nitrogen oxides and aerosols are covered. A number of topics are presented as a way of integrating the process view into the atmospheric context; these include the atmospheric oxidation efficiency, halogen and HO_x chemistry, nighttime chemistry, tropical chemistry, heat waves, megacities, biomass burning and the regional hot spot of the Mediterranean. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. Gaps and research questions that remain intractable are identified. The review concludes with a focus of research and policy questions for the coming decade. In particular, the policy challenges for concerted air quality and climate change policy (co-benefit) are discussed.     

Functional gene expression of oil-degrading bacteria resistant to hexadecane toxicity

Contamination with oil poses a threat to the environment and to human health worldwide. Biological methodologies have proved to be economical, versatile and efficient for the remediation of pollutants. In this paper, a highly efficient oil-degrading bacterial strain USTB-2 was isolated from an oil production well of Dagang oil field in Tianjin, China. The 16S rRNA sequence of USTB-2 showed 100% similarity with that of Bacillus subtilis BSn5. Hexadecane is one of the most important components in petroleum. The half inhibitory ratio (IC₅₀) of hexadecane inhibited organisms, determined by microcalorimetry, was lower in USTB-2 than in B. BSn5. The results indicate that the strain USTB-2 degrades hexadecane to make it less toxic compared with the normal strain. RT-PCR was used to evaluate the expression of oil-degrading enzymes, specifically 4-hydroxyphenylacetate 3-monooxygenase genes (HPMO). A sharp increase in the expression of HPMO genes was observed for USTB-2, while the expression of HPMO genes in reference strain B. BSn5 remained relatively stable. These methods can be used to study the metabolic potential of microorganisms for in situ oil decontamination.     

Effects of HMX exposure upon metabolic rate of northern bobwhite quail (Colinus virginianus) in ovo

We evaluated the use of the gas exchange rate as an ecologically relevant indicator of chemical stress in avian embryos/eggs. Northern bobwhite quail (Colinus virginianus) were exposed to octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) via feed containing nominal concentrations of 0, 12.5, 50.0, and 125.0 mg kg(-1). Metabolic rates (oxygen consumption) of developing quail eggs were then measured via respirometry to examine potential effects of HMX exposure. Metabolic rates were examined on 5, 9, and 21 d of incubation. Next, concentrations of HMX in embryos/eggs were determined by liquid chromatography-mass spectrometry. Mean (+/-SE) concentrations of HMX in eggs were 21.0+/-5.9, 1113+/-79.0, 3864+/-154.0, and 7426+/-301.1 ng g(-1) in control, low, medium and high dose groups, respectively. There were significant differences in oxygen consumption among the three embryo ages, however differences among the ages were not consistent among dose groups (age x dose group interaction p<0.0001). Oxygen consumption rates did not vary as a function of HMX in embryos (p=0.18). No evidence was observed for alterations of in ovo metabolic rates associated with HMX exposure.     

Impact caps: why population,affluence and technology strategies should be abandoned

This paper classifies strategies to reduce environmental impact according to the terms of the I = PAT formula. Policies limiting resource depletion and pollution (Impact) – by heavily taxing resources or rationing them on a country basis – are thus called ‘direct’ or ‘left-side’ strategies. Other policies to achieve the environmental goal of lowering Impact strive to limit Population and Affluence, or to use Technology to lower the ratio of resource inputs to goods-and-services outputs. Next it is shown that lowering any of these ‘right-side’ factors causes or at least enables the other two to rise or ‘rebound’. This has two consequences: 1) Since I = PAT does not express these interdependencies on the right side, it is more accurately written I = f(P,A,T); and 2) Success in lowering any of the right-side factors does not necessarily lower Impact. Rationing or Pigouvian taxation of resources or pollution, on the other hand, necessarily lower impact and are therefore preferable to population, consumption and technological environmental strategies. Finally, lifestyle and technology changes towards more sufficiency and efficiency would follow the caps as consumers and producers work to retain the greatest amount of welfare within the limits given.     

Total Factor Productivity Change in the New England Groundfish Fishery: 1964–1993

We develop estimates of total factor productivity (TFP) change in the New England groundfish fishery from 1964 to 1993, using a procedure similar to Squires' (1992, Rand J. Econom.23(2), 221–236) method, which extends standard TFP measurement by including the effect of fluctuations in stock abundance. The results indicate that TFP increased on average by 4.4% per year from 1964 to 1993. A higher average rate of increase occurred between 1964 and 1982, possibly due to new technologies (e.g., fishfinders). TFP declined at 0.33% annually from 1983 to 1993 due to stringent output and effort control measures.     

低碳高能,骑车出行没烦恼

<正>下午5点,一场大雨不期而至。史蒂夫站在窗前,心里不免有些失望,因为不能骑车回家了。史蒂夫是个不折不扣的骑行达人。在北京住了10年,换了4辆自行车。他的上一辆自行车报废之前,里程记录仪上留下的数字是3年18844公里,相当于绕二环576圈。10年间,从家门口的胡同开始,史蒂夫骑车转遍了鼓楼、故宫、工体、国贸和香山……从十三陵到南海子,从门头沟到通州,最后他甚至把车骑到了天津。可以这么说,只要是骑车能到达的地方,史蒂夫绝不选