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241.
William K. Modey Yanbo Pang Norman L. Eatough Delbert J. Eatough 《Atmospheric environment (Oxford, England : 1994)》2001,35(36):1282
Aerosol concentrations of carbonaceous material, sulfate, and nitrate for samples obtained using a newly designed PC-BOSS are reported. The results indicated that PM2.5 composition in Atlanta was dominated by sulfate and organic material, with low concentrations of particulate nitrate. Observed average particulate component concentrations for the 26-day study period were: sulfate, 12.2 μg/m3 (17.0 μg/m3 as ammonium sulfate); non-volatile organic material, 11.4 μg OM/m3 (assumes organic material, OM, is 61% C); semi-volatile organic compounds (SVOC) lost from particles during sampling, 5.3 μg OM/m3; filter retained nitrate, 0.1 μg/m3 (0.2 μg/m3 as ammonium nitrate); nitrate lost from particles, 0.3 μg/m3 (0.4 μg/m3 as ammonium nitrate); and soot (elemental carbon), 1.5 μg/m3. The PC-BOSS particle concentrator efficiency was obtained by comparison of the PC-BOSS sulfate data with sulfate data obtained from the Federal Reference Method (FRM) sampler. A modification of the PC-BOSS design to allow independent determination of this parameter is recommended. 相似文献
242.
Norman CS 《Journal of environmental management》2005,75(2):167-176
The Montreal Protocol on Substances that Deplete the Ozone Layer requires developed countries to phaseout methyl bromide production and non-quarantine uses by 2005 and developing countries to do the same by 2015. Exemptions to phaseout have been significant in slowing the process of abatement; many countries have applied for exemptions for some uses, partly on grounds that phaseout is economically infeasible. Data on the US strawberry market are used to investigate grower costs arising from substitution away from methyl bromide, the impact of trends in and characteristics of the demand for fresh strawberries, and characteristics of trade with countries not yet required to eliminate use of the compound. It appears that actual net costs to growers will be much smaller than the simple increase in production costs cited in the US nomination for exemption. 相似文献
243.
Slaton NA Brye KR Daniels MB Daniel TC Norman RJ Miller DM 《Journal of environmental quality》2004,33(5):1606-1615
Knowledge of the balance between nutrient inputs and removals is required for identifying regions that possess an excess or deficit of nutrients. This assessment describes the balance between the agricultural nutrient inputs and removals for nine geographical districts within Arkansas from 1997 to 2001. The total N, P, and K inputs were summed for each district and included inorganic fertilizer and collectable nutrients excreted as poultry, turkey, dairy, and hog manures. Nutrients removed by harvested crops were summed and subtracted from total nutrient inputs to calculate the net nutrient balance. The net balances for N, P, and K were distributed across the hectarage used for row crop, hay, pasture, or combinations of these land uses. Row-crop agriculture predominates in the eastern one-third and animal agriculture predominates in the western two-thirds of Arkansas. Nutrients derived from poultry litter accounted for >92% of the total transportable manure N, P, and K. The three districts in the eastern one-third of Arkansas contained 95% of the row-crop hectarage and had net N and P balances that were near zero or negative. The six districts in the western two-thirds of Arkansas accounted for 89 to 100% of the animal populations, had positive net balances for N and P, and excess P ranged from 1 to 9 kg P ha(-1) when distributed across row-crop, hay, and pasture hectarage. Transport of excess nutrients, primarily in poultry litter, outside of the districts in western Arkansas is needed to achieve a balance between soil inputs and removals of P and N. 相似文献
244.
Nitrogen and carbon leaching in agroecosystems and their role in denitrification potential 总被引:3,自引:0,他引:3
The drainage of water and leaching of dissolved constituents represent major components of agroecosystem mass budgets that have been exceedingly difficult to measure. Equilibrium-tension lysimeters (ETLs) were used to monitor drainage, nitrogen (N), and carbon (C) leaching through Plano silt loam (fine-silty, mixed, superactive, mesic Typic Argiudoll) for a 4-yr period in a restored prairie and N-fertilized no-tillage and chisel-plowed maize (Zea mays L.) agroecosystems. Mean drainage recorded during 4 yr for the prairie, no-tillage, and chisel-plowed ecosystems totaled 461, 1,116, and 1,575 mm and represented 16, 33, and 47% of precipitation plus melting of drifted snow received, respectively. Total inorganic N leaching losses during the 4-yr period for the prairie, no-tillage, and chisel-plowed ecosystems were 0.6, 201, and 179 kg N ha(-1), respectively. Inorganic N leaching represented 26 and 24% of applied fertilizer N additions to the no-tillage and chisel-plowed agroecosystems. Total dissolved C leaching losses were 119, 435, and 502 kg C ha(-1) for the prairie, no-tillage, and chisel-plowed ecosystems, respectively. Sufficient dissolved organic carbon (DOC) and nitrate N (NO3- -N) existed in the prairie and agroecosystems to support subsoil denitrification. Potential denitrification, however, was limited by insufficient lengths of saturated soil conditions in all three ecosystems, the supply of DOC in the agroecosystems, and the supply of nitrate N in the prairie. Based on available DOC and nitrate N, the maximum contribution of denitrification below the root zone in the agroecosystems was less than 25% of the total amount of leached nitrate N and the probable contribution of denitrification was much less. 相似文献
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247.
Norman Myers 《The Environmentalist》1987,7(3):163-174
Summary Our environmental situation continues to decline faster than ever. This is demonstrated by, the growing spread of pollution of both the water and atmospheric systems, erosion of topsoil, tropical deforestation, desertification, mass extinction of species, depletion of the ozone layer, and climatic dislocations. Compounding the impact of these problems is growth in human numbers in developing countries, together with the associated factor of extensive poverty. The author asks why our environmental situation should continue to decline, despite a remarkable outburst of awareness on the part of the general public and its political leaders since the time of the Stockholm Conference on the Human Environment. The author concludes that the problem does not lie with inadequate effort, rather with misdirected effort: we persist in tackling the symptoms of problems, rather than the problems themselves, let alone the sources of the problems. The paper broaches these issues within a context of fast-growing interdependence among the community of nations — both economic and ecological interdependence — which presents yet more problems, but also raises many opportunities for creative action.Professor Norman Myers is a consultant in environment and development. He has worked since 1970 on the general subject area of environment and natural resources, with emphasis on species, gene reservoirs and tropical forests. He was undertaken this consultancy work for the Rockefeller Brothers Fund, US National Academy of Sciences, the World Bank, OECD, the Smithsonian Institution, UN agencies, World Resources Institute, US National Research Council and IUCN, among other organizations. His main professional interest lies with resource relationships between the developed and developing worlds.Among his recent publications areThe Sinking Ark (Pergamon Press, Oxford and New York, 1979);Conversion of Tropical Moist Forests (National Research Council, Washington D.C., 1980);A Wealth of Wild Species (Westview Press, Boulder, Colorado, 1983);The Primary Source (W. W. Norton, New York, 1984); andThe Gaia Atlas of Planet Management (Doubleday, New York, and Pan Books, London, 1985).Norman Myers is an Advisory Board Member and regular contributor toThe Environmentalist. 相似文献
248.
Norman L. Miller Jinwon Kim Robert K. Hartman John Farrara 《Journal of the American Water Resources Association》1999,35(6):1525-1537
ABSTRACT: Downscaling coarse resolution climate data to scales that are useful for impact assessment studies is receiving increased attention. Basin-scale hydrologic processes and other local climate impacts related to water resources such as reservoir management, crop and forest productivity, and ecosystem response require climate information at scales that are much finer than current and future GCM resolutions. The Regional Climate System Model (RCSM) is a dynamic downscaling system that has been used since 1994 for short-term precipitation and streamflow predictions and seasonal hindcast analysis with good skill. During the 1997–1998 winter, experimental seasonal forecasts were made in collaboration with the NOAA Climate Prediction Center and UCLA with promising results. Preliminary studies of a control and 2°CO2 perturbation for the southwestern U.S. have been performed. 相似文献
249.
Quantifying climate change mitigation potential in the United States Great Plains wetlands for three greenhouse gas emission scenarios 总被引:1,自引:0,他引:1
250.
Elke I. Zimmer Thomas G. Preuss Steve Norman Barbara Minten Virginie Ducrot 《Environmental Sciences Europe》2018,30(1):36