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831.
Pablo R. Dalmasso Raúl A. Taccone Jorge D. Nieto Pablo M. Cometto Silvia I. Lane 《Atmospheric environment (Oxford, England : 1994)》2010,44(14):1749-1753
Using the relative rate technique, rate constants for the gas-phase reactions of hydroxyl radicals with 2-chloroethyl methyl ether (k1), 2-chloroethyl ethyl ether (k2) and bis(2-chloroethyl) ether (k3) have been measured. Experiments were carried out at (298 ± 2) K and atmospheric pressure using synthetic air as bath gas. Using n-pentane and n-heptane as reference compounds, the following rate constants were derived: k1 = (5.2 ± 1.2) × 10?12, k2 = (8.3 ± 1.9) × 10?12 and k3 = (7.6 ± 1.9) × 10?12, in units of cm3 molecule?1 s?1. This is the first experimental determination of k2 and k3 under atmospheric pressure. The rate constants obtained are compared with previous literature data and the observed trends in the relative rates of reaction of hydroxyl radicals with the ethers studied are discussed. The atmospheric implications of the results are considered in terms of lifetimes and fates of the hydrochloroethers studied. 相似文献
832.
D. Martin C.S. Price I.R. White G. Nickless K.F. Petersson R.E. Britter A.G. Robins S.E. Belcher J.F. Barlow M. Neophytou S.J. Arnold A.S. Tomlin R.J. Smalley D.E. Shallcross 《Atmospheric environment (Oxford, England : 1994)》2010,44(25):3043-3052
As part of the DAPPLE programme two large scale urban tracer experiments using multiple simultaneous releases of cyclic perfluoroalkanes from fixed location point sources was performed. The receptor concentrations along with relevant meteorological parameters measured are compared with a three screening dispersion models in order to best predict the decay of pollution sources with respect to distance. It is shown here that the simple dispersion models tested here can provide a reasonable upper bound estimate of the maximum concentrations measured with an empirical model derived from field observations and wind tunnel studies providing the best estimate. An indoor receptor was also used to assess indoor concentrations and their pertinence to commonly used evacuation procedures. 相似文献
833.
Ch. Vlachokostas S.A. Nastis Ch. Achillas K. Kalogeropoulos I. Karmiris N. Moussiopoulos E. Chourdakis G. Banias N. Limperi 《Atmospheric environment (Oxford, England : 1994)》2010,44(28):3352-3361
This study aims at presenting a combined air quality and GIS modelling methodological approach in order to estimate crop damages from photochemical air pollution, depict their spatial resolution and assess the order of magnitude regarding the corresponding economic damages. The analysis is conducted within the Greater Thessaloniki Area, Greece, a Mediterranean territory which is characterised by high levels of photochemical air pollution and considerable agricultural activity. Ozone concentration fields for 2002 and for specific emission reduction scenarios for the year 2010 were estimated with the Ozone Fine Structure model in the area under consideration. Total economic damage to crops turns out to be significant and estimated to be approximately 43 M€ for the reference year. Production of cotton presents the highest economic loss, which is over 16 M€, followed by table tomato (9 M€), rice (4.2 M€), wheat (4 M€) and oilseed rape (2.8 M€) cultivations. Losses are not spread uniformly among farmers and the major losses occur in areas with valuable ozone-sensitive crops. The results are very useful for highlighting the magnitude of the total economic impacts of photochemical air pollution to the area’s agricultural sector and can potentially be used for comparison with studies worldwide. Furthermore, spatial analysis of the economic damage could be of importance for governmental authorities and decision makers since it provides an indicative insight, especially if the economic instruments such as financial incentives or state subsidies to farmers are considered. 相似文献
834.
Vo Thi Thanh Loc Simon R. Bush Le Xuan Sinh Nguyen Tri Khiem 《Environment, Development and Sustainability》2010,12(6):889-908
This paper investigates the structure, function and wealth distribution within the Pangasius hypophthalmus and Henicorhynchus spp./Labiobarbus spp. value chains in the Mekong Delta of Vietnam. The analysis is driven by key questions relating to the form and function
of value chains, their contribution to the livelihoods of farmers and fishers, the effectiveness of government policy and
the potential for value chain governance mechanisms, such as contracts and certification, to steer towards sustainable production.
The results indicate that actors in the high value Pangasius hypopthalmus export chain have a higher potential income, but face considerably higher economic vulnerability from global markets. Alternatively,
Henichorhychus/Labiobarbus spp. fishers are severely constrained in their ability to negotiate higher prices for their fish but appear to be less vulnerable
to economic and environmental change. The paper concludes that for value chain governance to improve the livelihoods of fishers
and farmers in both high and low value chains, new arrangements are needed that better accommodate customary institutions
and informal market relations. 相似文献
835.
Developed countries are major markets for developing country fresh produce. Demand by developed country consumers for spotless
produce has encouraged developing country consumers to rely increasingly on pesticides in producing fresh export vegetables.
However developed country pesticide standards enacted in response to reports of increased farmer and farm worker pesticide
poisoning and the food safety scandals of the 1980s and 1990s require changes in the way growers use pesticides. The EU has
especially developed stringent food safety standards relating to, among other things, pesticide usage. Under EU pesticide
standards (EU-PS) farmers are trained by their buyers on safe use of pesticides and then closely monitored under contract.
This paper looks at the impact of these standards on developing country farmers’ use of alternative pest management practices,
pesticide protective clothing and the actual usage of pesticides. It finds that compliance with EU-PS increases the use of
alternative pest management practices and protective clothing. However, EU-PS has mixed effect on the quantity of pesticides
used. The paper also finds that farmer’s education and access to information play an important role in the use of alternative
pest management practices. The paper concludes that EU-PS encourage the use of alternative pest management practices and pesticide
protective gear in production of fresh export vegetables. The findings imply that EU-PS promote environmentally-friendly methods
of production of fresh export vegetables in developing countries. 相似文献
836.
837.
J. Ram Pillarisetti Jeroen C. J. M. van den Bergh 《Environment, Development and Sustainability》2010,12(1):49-62
What is a ‘sustainable nation’ and how can we identify and rank ‘sustainable nations?’ Are nations producing and consuming in a sustainable way? Although several aggregate indexes have been proposed to answer such questions, comprehensive and internationally comparable data are not available for most of these. This paper quantitatively compares three aggregate indexes of sustainability: the World Bank’s ‘Genuine Savings’ measure, the ‘Ecological Footprint,’ and the ‘Environmental Sustainability Index.’ These three indexes are available for a large number of countries and also seem to be the most influential among the aggregate indexes. This paper first discusses the main limitations and weaknesses of each of these indexes. Subsequently, it shows that rankings of sustainable nations and aggregate assessments of unsustainable world population and world GDP shares vary considerably among these indexes. This disagreement leads to suggestions for analysis and policy. One important insight is that climate change, arguable the most serious threat currently faced by humanity, is not or arbitrarily captured by the indexes. 相似文献
838.
Exporting natural capital: the foreign eco-footprint on Costa Rica and implications for sustainability 总被引:1,自引:0,他引:1
As the world economy ‘globalizes’, trade has become a major mechanism by which much of the human population supports its needs.
While trade in resource commodities (natural income) can increase the well-being of people in both exporting and importing
countries, it can also lead to depletion of natural capital and the loss of ecosystems integrity. In recent years, various
researchers have attempted to address this problem using a consumption-based perspective on ecological change. Their work
shows that the loss of ecosystem integrity in almost any region of the world can be attributed to both local and international
consumer demand. This paper illustrates the utility of modified eco-footprint analysis in assessing export-related ecological
change in Costa Rica. We quantify ecological footprint of consumers around the world on the productive ecosystems of Costa
Rica, document the changing character of this footprint and highlight some of the linkages between production for export in
Costa Rica and ecological degradation. We then discuss the implications of the increasing trade-based entanglement of nations
for ecosystems and global sustainability. 相似文献
839.
Kris A. G. Wyckhuys Robert J. O’Neil 《Environment, Development and Sustainability》2010,12(3):297-311
In subsistence farming systems of the developing world, adoption of resource-conserving practices such as integrated pest
management (IPM) is often strikingly low. This has partially been ascribed to researchers’ limited understanding of how technologies
develop at the interface of the systems’ social and ecological components. In Honduras (Central America), there exists concern
about limited adoption and diffusion of IPM technologies in certain smallholder production systems. In this study, we determine
social and ecological drivers of IPM adoption in subsistence maize production in the country’s hillside environment. Honduran
small-scale maize production is typified by a key insect pest (the fall armyworm, Spodoptera frugiperda) being partly kept at bay through action of a diverse natural enemy complex, including ants, social wasps, carabid beetles,
and spiders. Local agricultural landscapes, primarily shaped through shifting cultivation, provide key resources to maintain
this natural enemy diversity. These local ecological conditions and related natural enemy abundance strongly influence farmers’
agroecological knowledge and pest management practices. In the meantime, farmer practices are also affected by local communication
networks, which help validate and spread IPM concepts and technologies. Based on our findings, we advocate a holistic approach
to improve IPM extension through mapping of agroecological opportunities, visualization of regional patterns in farmer knowledge,
and associated priority setting. Local IPM capacity could be built through institutional strengthening and adaptive comanagement,
while IPM training should be linked with natural resource management initiatives. These approaches may eventually improve
the way IPM is delivered to small-scale farmers who operate in the ecologically diverse environments of the tropics. 相似文献
840.
The abundance of terrestrial arthropods in the Orenburgskii Nature Reserve has decreased since its establishment in 1989.
At present, this parameter fluctuates considerably, and the species composition of arthropods is changing in favor of xerobiontic
and eurybiontic species. These changes result from the absence of grazing load as well as from periodic fires. Therefore,
it is necessary to organize controlled livestock grazing and reliable fire protection in reserved areas. 相似文献