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241.
Sofia Thorsson Björn Holmer Andreas Andjelic Jenny Lindén Sandra Cimerman Lars Barregard 《Environmental monitoring and assessment》2014,186(7):4479-4492
A majority of households in developing countries rely on biomass fuel for cooking, typically burned in open fires or simple stoves. The incomplete combustion of these fuels causes adverse health effects such as respiratory diseases, especially among women and children. However, quantitative data on pollution levels and on associated diseases are limited. We examined cooking habits and self-reported health in 31 households with outdoor open wood fires in Ouagadougou, Burkina Faso, using structured interviews. In eight households, carbon monoxide (CO) was measured using passive sampling. In addition, meteorology and ambient CO concentrations were assessed. The average CO concentration during cooking was 4.3 ppm, with a maximum of 65.3 ppm and minimum of 0.3 ppm (1-min values). A clear daily pattern was observed, with relatively low concentrations during the day and high during the evening, occasionally exceeding the World Health Organization 1- and 8-h guidelines when the air stabilised. On average, CO concentrations were 43 % higher in kitchens located in closed yards than in those located in open yards, showing that fireplace location affected the levels. Eye irritation and coughing among women and children were reported by 30 % of the households. Based on previously reported relations between CO concentrations and fine particles (<2.5 μm), the exposure to biomass smoke appears to be high enough to pose a considerable health risk among women and children in households with outdoor open wood fires. The results suggest that burning should be limited between sunset and dawn and in areas with limited ventilation to reduce pollutions levels. 相似文献
242.
The impact of climate changes on the pollution levels in Denmark is the major topic of this paper. Variations of the Danish air pollution levels that are caused by climatic changes are studied together with variations caused by other factors (emissions, inter-annual variability of meteorological conditions, etc.). The Unified Danish Eulerian Model (UNI-DEM) was run on a fine, 10 km × 10 km, grid over a space domain covering all of Europe to minimize the influence of the boundary conditions on the Danish pollution levels. This study is based on four categories of scenarios: (i) traditional scenarios, (ii) climatic scenarios, (iii) scenarios with variations of the human-made (anthropogenic) emissions and (iv) scenarios in which the biogenic emissions were varied. The total number of applied scenarios was 14, and a time-period of 16 years was used. The results show clearly that although the concentrations of the major pollutants do not depend too much on the climatic changes, some quantities, in particular quantities related to high ozone levels, might be increased significantly as a result of the warming trends in the future climate. The reason for this phenomenon is explained. 相似文献
243.
Effects of bioturbation on the fate of oil in coastal sandy sediments--an in situ experiment 总被引:1,自引:0,他引:1
Effects of bioturbation by the common lugworm Arenicola marina on the fate of oil hydrocarbons (alkanes and PAHs) were studied in situ during a simulated oil spill in a shallow coastal area of Roskilde fjord, Denmark. The fate of selected oil compounds was monitored during 120 d using GC-MS and bioturbation activity (feces production and irrigation) was measured regularly during the experiment and used as input parameters in a mechanistic model describing the effects of A. marina on the transport and degradation of oil compounds in the sediment. The chemical analytical data and model results indicated that A. marina had profound and predictable effects on the distribution, degradation and preservation of oil and that the net effect depended on the initial distribution of oil. In sediment with an oil contaminated subsurface-layer A. marina buried the layer deeper in the sediment which clearly enhanced oil persistence. Conversely, A. marina stimulated both the physical removal and microbial degradation of oil compounds in uniformly oil contaminated sediments especially in deeper sediment layers (10-20 cm below the surface), whereas the fate of oil compounds deposited in surface layers (0-5 cm) mainly was affected by removal processes induced by wave actions and other bioturbating infauna such as Nereis diversicolor, Corophium volutator and Hydrobia spp. present in the experimental plots. 相似文献
244.
Decomposition studies were carried out at sites throughout Sweden, including the four Integrated Monitoring sites. Scots pine
needle litterbag weight loss measurements over 3 or 5 years were determined at 26 sites and repeated up to 27 times, depending
on the site. Humus layer respiration rates were determined for 20 sites in 1987–1989 and repeated in 2007–2008. Partial Least
Squares (PLS) regression was used to elucidate the relative importance of climatic and soil factors. Annual needle weight
losses decreased only slowly (20–10%) over 3–5 years for all northern (>60°N) sites but decreased sharply from 30 to 10% in
the third year in southern (<60°N) sites. Respiration rates of southern sites were less (40% on average) than those of northern
sites. Humus layer N was positively correlated to needle weight loss during the first and the second years, but negatively
correlated in the third year and to respiration rates. The results indicated that litter formed in southern Sweden became
more recalcitrant in later stages of decomposition compared to litter produced in northern Sweden. 相似文献
245.
A unique long term, 49-year record (divided into three time periods 1961–1976, 1977–1992, and 1993–2009) of snow profile stratigraphy
from the Swedish sub Arctic, was analyzed with a focus on changes in snow characteristics. The data set contained grain size,
snow layer hardness, grain compactness, and snow layer dryness, observed every second week during the winter season. The results
showed an increase in very hard snow layers, with harder snow in early winter and more moist snow during spring. There was
a striking increase in the number of observations with very hard snow at ground level over time. More than twice as many occasions
with hard snow at ground level were observed between 1993 and 2009 compared to previous years, which may have a significant
effect on plants and animals. The changes in snow characteristics are most likely a result of the increasing temperatures
during the start and the end of the snow season. 相似文献
246.
By mainly targeting larger predatory fish, commercial fisheries have indirectly promoted rapid increases in densities of their
prey; smaller predatory fish like sprat, stickleback and gobies. This process, known as mesopredator release, has effectively
transformed many marine offshore basins into mesopredator-dominated ecosystems. In this article, we discuss recent indications
of trophic cascades on the Atlantic and Baltic coasts of Sweden, where increased abundances of mesopredatory fish are linked
to increased nearshore production and biomass of ephemeral algae. Based on synthesis of monitoring data, we suggest that offshore
exploitation of larger predatory fish has contributed to the increase in mesopredator fish also along the coasts, with indirect
negative effects on important benthic habitats and coastal water quality. The results emphasize the need to rebuild offshore
and coastal populations of larger predatory fish to levels where they regain their control over lower trophic levels and important
links between offshore and coastal systems are restored. 相似文献
247.
Repeated fertilization of forests to increase biomass production is an environmentally controversial proposal, the effects
of which we assessed on breeding birds in stands of young Norway spruce (Picea abies), in an intensively managed forest area in southern Sweden. Our results show that fertilized stands had 38% more species
and 21% more individuals than unfertilized stands. Compared with stands under traditional management, the further intensification
of forestry by repeated applications of fertilizers thus seemed to enhance species richness and abundance of forest birds.
We cannot conclude at this stage whether the response in the bird community was caused by changes in food resources or increased
structural complexity in the forest canopy due to the skid roads used for the application of the fertilizers. Future studies
should focus on structural and compositional effects of fertilization processes during the entire rotation period and at assessing
its effects in a landscape context. 相似文献
248.
Lars Olof Nord Rahul Anantharaman Marvin Rausand Olav Bolland 《International Journal of Greenhouse Gas Control》2009,3(4):411-421
Most of the current CO2 capture technologies are associated with large energy penalties that reduce their economic viability. Efficiency has therefore become the most important issue when designing and selecting power plants with CO2 capture. Other aspects, like reliability and operability, have been given less importance, if any at all, in the literature.This article deals with qualitative reliability and operability analyses of an integrated reforming combined cycle concept. The plant reforms natural gas into a syngas, the carbon is separated out as CO2 after a water-gas shift section, and the hydrogen-rich fuel is used for a gas turbine. The qualitative reliability analysis in the article consists of a functional analysis followed by a failure mode, effects, and criticality analysis (FMECA). The operability analysis introduces the comparative complexity indicator (CCI) concept.Functional analysis and FMECA are important steps in a system reliability analysis, as they can serve as a platform and basis for further analysis. Also, the results from the FMECA can be interesting for determining how the failures propagate through the system and their effects on the operation of the process. The CCI is a helpful tool in choosing the level of integration and to investigate whether or not to include a certain process feature. Incorporating the analytical approach presented in the article during the design stage of a plant can be advantageous for the overall plant performance. 相似文献
249.
Anne Orderdalen Steen Torunn Berg Ashu P. Dastoor Dorothy A. Durnford Lars Robert Hole Katrine Aspmo Pfaffhuber 《Atmospheric environment (Oxford, England : 1994)》2009,43(35):5604-5610
From February 29 until June 15 2008 gaseous elemental mercury (GEM) fluxes above a snow covered surface was measured in Ny-Ålesund, Svalbard using a GEM flux gradient method. A clear seasonal pattern in the meteorological variables associated with the GEM flux was observed. For the first time in Ny-Ålesund a net deposition of GEM was recorded during polar night, despite the lack of Atmospheric Mercury Depletion Events (AMDE). 7500 ng m−2 GEM was emitted from the surface snow to the air during the entire study. The depositions of GEM and reactive gaseous mercury (RGM) were calculated to be 1500 and 1000 ng m−2, respectively, during the same time period. The GEM fluxes reported in this study were found to be comparable to GEM fluxes measured at other Arctic locations (i.e. Alert and Barrow), suggesting that GEM acts in a similar way throughout the Arctic. An assessment of the GEM flux gradient method used discovered a non-linear GEM concentration profile. The nonlinearity was explained by a non-stationary turbulence regime. The GEM flux calculated was not found to be representative for the entire surface boundary layer. 相似文献
250.
Lars Harms-Ringdahl 《Safety Science》2009,47(3):353-363
A new method for accident investigations is presented. It is based on the concept of safety function, which is defined as a technical or organisational function, a human action or a combination of these, that can reduce the probability and/or consequences of accidents and other unwanted events in a system. An analysis starts with the identification of safety functions related to the event. These are structured; an assessment is then made of whether they worked or not, and finally safety improvements are proposed.The method has been applied to five different incidents, coming from different types of work sites, such as electrical power distribution, a railway, and hospitals. For each case, around 40 safety functions were identified, of which less than half had worked. It was found that technical, organisational and human safety features existed side-by-side. The method supports a consistent analysis of a variety of safety features, and can integrate them into a common format.Each system contained formal and informal elements in parallel, often overlapping. This can be seen as safety redundancy, which makes the safety system less vulnerable to change that supports the preservation of safety. It might be more adequate to describe this as a safety web rather than a distinct set of barriers, and there is also an analogy with the concept of safety resilience. 相似文献