Biotic landfill cover treatments for mitigating methane emissions

Landfill methane (CH₄) emissions have been cited as one ofthe anthropogenic gas releases that can and should be controlledto reduce global climate change. This article reviews recent research that identifies ways to enhance microbial consumptionof the gas in the aerobic portion of a landfill cover. Use of these methods can augment CH₄ emission reductions achievedby gas collection or provide a sole means to consume CH₄ atsmall landfills that do not have active gas collection systems.Field studies indicate that high levels of CH₄ removal can be achieved by optimizing natural soil microbial processes. Further, during biotic conversion, not all of the CH₄ carbonis converted to carbon dioxide (CO₂) gas and released to theatmosphere; some of it will be sequestered in microbial biomass.Because biotic covers can employ residuals from other municipalprocesses, financial benefits can also accrue from avoided costsfor residuals disposal.     

Global methane emissions from the world coal industry

The Coal Industry Advisory Board (CIAB) of the International Energy Agency (IEA) estimated the total methane emissions from worldwide mining, treatment and storage of coal to be approximately 25 million tonnes/year for 1990. Slightly more than one million tonnes of methane are utilized by the industry. Thus, the net annual discharge to the atmosphere is 24 million tonnes. Methane emissions data were available for the U.S., the U.K., former U.S.S.R., Australia, China, Germany, Poland and Czechoslovakia. Methane emissions for India and S. Africa were estimated from a linear correlation between the average depth of mining and specific methane emissions derived from the available data for the eight countries. These ten largest coal producing countries represented nearly 90% of world coal production in 1990. Total methane emissions for the world coal industry were calculated by prorating the methane emissions from these ten countries in proportion to coal production.The reported values represent the best international data available at present. The net total emissions of 24 million tonnes/year are substantially less than some previously reported indirect estimations and constitute only 4 to 6% of the global methane emissions.     

Determination of European methane emissions,using concentration and isotope measurements

The determination of methane emissions on a regional scale is needed in order to reduce some of the uncertainties in the global methane budget. Our measurements of the concentration and the Carbon-13 isotope composition (¹³C) of atmospheric methane are, combined with trajectories, used to get insight in the type and size of the methane emissions of a large area.     

Methane emissions of differently fed dairy cows and corresponding methane and nitrogen emissions from their manure during storage

This study investigated the effects of supplementing 40 g lauric acid (C₁₂) kg^-1 dry matter (DM) in feed on methane emissions from early-lactating dairy cows and the associated effects on methane, nitrous oxide and ammonia release from the manure during storage. Stearic acid (C₁₈), a fatty acid without assumed methane-suppressing potential in the digestive tract of ruminants, was added at 40 g kg^-1 DM to a control diet. The complete feed consisted of forage and concentrate in a ratio of 1.5:1 (DM basis). The manure was stored for 14 weeks either as complete slurry or, separately, as urine-rich slurry and farmyard manure representing two common storage systems. Methane release of the cows, as measured in respiratory chambers, was lower with C₁₂ by about 20%, but this was mostly resulting from a reduced feed intake and, partly, from a lower rate of fibre digestion. As milk yield declined less than feed intake, methane emission per kg of milk was significantly lower with C₁₂ (11.4 g) than with C₁₈ (14.0 g). Faeces of C₁₂-fed cows had a higher proportion of undigested fibre and accordingly methane release from their manure was higher compared with the manure obtained from the C₁₈-fed cows. Overall, manure-derived methane accounted for8.2% and 15.4% of total methane after 7 and 14 weeks of storage, respectively. The evolution of methane widely differed between manure types and dietary treatments, with a retarded onset of release in complete slurry particularly in the C₁₂ treatment. Emissions of nitrous oxide were lower in the manures from the C₁₂ treatment. This partially compensated for the higher methane release from the C₁₂ manure with respect to the greenhouse gas potential. The total greenhouse gas potential (cow and manure together) accounted for 8.7 and 10.5 kg equivalents of CO₂ cow^-1 d^-1with C₁₂ and C₁₈, respectively. At unaffected urine-N proportion ammonia and total nitrogen losses from stored manure were lower with C₁₂ than with C₁₈ corresponding to the differences in feed and nitrogen intake. The present results suggest that manure storage significantly contributes to total methane emission from dairy husbandry, and that the identification of effective dietary mitigation strategies has to consider both the digestive tract of the animals and the corresponding manure.     

Anthropogenic emissions of methane and nitrous oxide in the Federal Republic of Germany

The anthropogenic emission sources of methane (CH₄) and nitrous oxide (N₂O) in the Federal Republic of Germany were investigated. The object of the recently completed first phase of this research project was to summarize the present knowledge about the emission sources, make a first rough estimate of the emissions, identify the need for further research in the field, and - as far as possible - discuss the existing possibilities to reduce emissions. The main CH₄ emission sources identified are the landfills, stock farming and pit mining, the main N₂O sources are agriculture (including a minor contribution from animal wastes) and the production of adipic acid, the latter possibly being reducible by means of a new catalytic process. The total anthropogenic emissions of CH₄ from Germany are estimated at 5.4 – 7.7 million tonnes per year, contributing a share of roughly 2 % to the world-wide anthropogenic emissions (350 million t/a). Those of N₂O are estimated at 200 000 – 280 000 tonnes per year (world-wide 1.4 – 6.5 million t/a).     

Diurnal variation of methane emissions from an alpine wetland on the eastern edge of Qinghai-Tibetan Plateau

Alpine wetland is a source for CH₄, but little is known about methane emission from such wetland, especially about its diurnal pattern. In this study we tried to probe the diurnal variation in methane emission from alpine wetland vegetation. The average methane emission rate was 9.6 ± 3.4 mg CH₄ m^???2 h^???1. There was an apparent diurnal variation pattern in methane emission with one minor peak at 06:00 and a major one at 15:00. The sunrise peak was consistent with a two-way transport mechanism for plants (convective at daytime and diffusive at night-time). CH₄ emission was found significantly correlated with redox potentials. The afternoon peak could not be explained by diurnal variation in soil temperature, but could be attributable to changes in CH₄ oxidation and production driven by plant gas transport mechanism. The results have important implications for sampling and scaling strategies for estimating methane emission from alpine wetlands.     

Estimation of methane and nitrous oxide emissions from rice field with rice straw management in Cambodia

To estimate the greenhouse gas emissions from paddy fields of Cambodia, the methodology of the Intergovernmental Panel on Climate Change (IPCC) guidelines, IPCC coefficients, and emission factors from the experiment in Thailand and another country were used. Total area under rice cultivation during the years 2005–2006 was 2,048,360 ha in the first crop season and 298,529 ha in the second crop season. The emission of methane from stubble incorporation with manure plus fertilizer application areas in the first crop season was estimated to be 192,783.74 ton higher than stubble with manure, stubble with fertilizer, and stubble without fertilizer areas. The fields with stubble burning emitted the highest emission of methane (75,771.29 ton) followed by stubble burning with manure (22,251.08 ton), stubble burning with fertilizer (13,213.27 ton), and stubble burning with fertilizer application areas (3,222.22 ton). The total emission of methane from rice field in Cambodia for the years 2005–2006 was approximately 342,649.26 ton (342.65 Gg) in the first crop season and 36,838.88 ton (36.84 Gg) in the second crop season. During the first crop season in the years 2005–2006, Battambang province emitted the highest amount of CH₄ (38,764.48 ton) and, in the second crop season during the years 2005–2006, the highest emission (8,262.34 ton) was found in Takeo province (8,262.34 ton). Nitrous oxide emission was between 2.70 and 1,047.92 ton in the first crop season and it ranged from 0 to 244.90 ton in the second crop season. Total nitrous oxide emission from paddy rice field was estimated to be 9,026.28 ton in the first crop season and 1,091.93 ton in the second crop season. Larger area under cultivation is responsible for higher emission of methane and nitrous oxide. Total emission of nitrous oxide by using IPCC default emission coefficient was approximately 2,328.85 ton. The total global warming potential of Cambodian paddy rice soil is 11,723,217.03 ton (11,723 Gg) equivalents of CO₂.     

Consumption of methane by soils

Measurements of the methane flux and methane concentration profiles in soil air are presented. The flux of methane from the soil is calculated by two methods: a) Direct by placing a static open chamber at the soil surface. b) Indirect, using the ²²²Rn concentrations profile and the ²²²Rn flux in the soil surface in parallel with the methane concentration (²²²Rn calibrated fluxes). The methane flux has been determined in two kinds of soils (sandy and loamy) in the surroundings of Málaga (SPAIN). The directly measured methane fluxes at all investigated sites is higher than methane fluxes derived from Rn calibrated fluxes. Atmospheric methane is consumed by soils, mean direct flux to the atmosphere were - 0.33 g m^–2yr-1. The direct methane flux is the same within the measuring error in sandy and loamy soils. The influence of the soil parameters on the methane flux indicates that microbial decomposition of methane is primarily controlled by the transport of methane.     

Air Pollution Estimates in Guadalajara City

A method for estimating the impact of industrial emissions is suggested and applied to the Guadalajara City Metropolitan Area (GCMA). The method is based on solutions to the pollution transport model and its adjoint. Two equivalent direct and adjoint mean pollution concentration estimates are considered for ecologically important zones of the GCMA. The dependence of these estimates on the number, positions and emission rates of industrial plants, as well as on the wind and initial pollution distribution in the GCMA is qualitatively and quantitatively examined. It is shown that the adjoint model solutions serve as the influence functions providing valuable information on the role of each of the industrial plants in polluting different zones within the GCMA. These solutions have been calculated with a balanced and absolutely stable second-order finite-difference scheme based on the splitting method. A method for an optimal allocation of a new industrial plant is considered.     

汽车尾气遥感监测

介绍一种先进的汽车尾气监测技术,即遥感监测的工作原理、检测系统的组成、现场设置、遥感监测的优点、实际应用及其与传统监测方法检测结果的相关性.     

Possible markers of traffic-related emissions

Looking for robust indicators of motor vehicle emissions it has been found that brake wear and linings are significant contributors of Cu, Mo and Sb to air particulate matter. These trace elements, whose mutual ratios in airborne particulate matter resulted quite different from those in crustal material, appear to be available fingerprinting tools to identify the contribution of on-road vehicles to traffic-derived particulate matter. In this study, the results of analytical determinations of Cu, Mo and Sb on PM(10), PM(2.5), vegetation and brake dust samples, together with gas (CO, NOx) concentrations, are discussed. Highly significant correlations among Cu, Sb and Mo were observed in particulate matter from Palermo and between Cu-Sb and Cu-Mo at Catania. Further significant positive correlations have been found in pine needles from Palermo, Gela and in platanus leaves from Catania.     

Direct and Adjoint Oil Spill Estimates

Propagation of the oil spilling from a damaged oil tanker is considered in a limited sea area. The accident consequences are evaluated by means of direct and adjoint oil concentration estimates in ecologically sensitive zones. While the direct estimates are preferable to get a comprehensive idea of the oil spill impact on the whole area, the adjoint ones are useful and economical in studying the sensitivity of the oil concentration in some zones to variations in the accident site and oil spill rate from the tanker. Thanks to special boundary conditions set at the inflow and outflow parts of the open boundary, the main and adjoint oil transport problems are both well-posed according to Hadamard (1923). The estimates obtained in Skiba (1996a) are generalized to the three dimensions. Balanced, absolutely stable 2nd-order finite-difference schemes based on the splitting method are constructed for the two- and three-dimensional cases, both. The main and adjoint schemes are compatible in the sense that at every fractional step of the splitting algorithm, the one-dimensional split operators of both the schemes satisfy a discrete form of the Lagrange identity (Marchuk, 1995). In the special unforced and non-dissipative case, the schemes have two conservation laws each. Each split problem is solved by the factorization method.     

Methane emissions from natural wetlands

Methane is considered one of the most important greenhouse gases in the atmosphere. Because of the strict anaerobic conditions required by CH₄-generating microorganisms, natural wetland ecosystems are one of the main sources of biogenic CH₄. The total natural wetland area is estimated to be 5.3 to 5.7 × 10¹² m², making up less than 5% of the Earth's land surface. However, natural wetland plays a disproportionately large role in CH₄ emissions. Wetlands are likely the largest natural sources of CH₄ to the atmosphere, accounting for about 20% of the current global annual emission. Out of the total amount of CH₄ emitted, northern wetlands contribute 34%, temperate wetlands 5%, and tropical systems about 60%.Because of the unique characteristics and high productivity, wetland ecosystems are important in the global carbon cycle. Natural wetlands are permanently or temporarily saturated. Strict anaerobic conditions consequently develop, which allows methanogenesis to occur. But the thin oxic layer and the oxic plant rhizophere promote activity of CH₄-oxidizing bacteria or methanotrophs. Thus, both CH₄ formation and consumption in wetland systems are microbiological processes and are controlled by many factors. Eight of the controlling factors, including carbon supply, soil oxidation-reduction status, pH, temperature, vegetation, salinity and sulfate content, soil hydrological conditions and CH₄ oxidation are discussed in this paper.     

Estimates of soil erosion using cesium-137 tracer models

The soil erosion was studied by ¹³⁷Cs technique in Yatagan basin in Western Turkey, where there exist intensive agricultural activities. This region is subject to serious soil loss problems and yet there is not any erosion data towards soil management and control guidelines. During the soil survey studies, the soil profiles were examined carefully to select the reference points. The soil samples were collected from the slope facets in three different study areas (Kırtas, Peynirli and Kayısalan Hills). Three different models were applied for erosion rate calculations in undisturbed and cultivated sites. The profile distribution model (PDM) was used for undisturbed soils, while proportional model (PM) and simplified mass balance model (SMBM) were used for cultivated soils. The mean annual erosion rates found using PDM in undisturbed soils were 15 t ha⁻¹ year⁻¹ at the Peynirli Hill and 27 t ha⁻¹ year⁻¹ at the Kırtas Hill. With the PM and SMBM in cultivated soils at Kayışalan, the mean annual erosion rates were obtained to be 65 and 116 t ha⁻¹ year⁻¹, respectively. The results of ¹³⁷Cs technique were compared with the results of the Universal Soil Loss Equation (USLE).     

Enhanced Wet Deposition Estimates using Modeled Precipitation Inputs

Effective assessments of linkages between atmospheric deposition and sensitive aquatic and terrestrial ecosystems require a knowledge of spatial patterns in deposition of greater resolution than currently available using point estimates and two-dimensional surface algorithms. A high resolution wet deposition model was developed for the Eastern U.S.A. by incorporating daily precipitation measurements from National Oceanic and Atmospheric Administration (NOAA) monitoring sites located within the Eastern U.S.A.; topographic variables, including elevation, slope, and aspect that affect the amount and distribution of precipitation across the region; and precipitation chemistry data from National Atmospheric Deposition Program (NADP) sites within and adjacent to the region. Model performance, which was tested against independent measurements from three physiographic regions of the eastern U.S.A., revealed a statistically significant reduction in interpolation error compared to traditional two-dimensional surface algorithms.     

Reporting emissions of greenhouse gases in Canada

Non-carbon dioxide greenhouse gases are considered in Canada's National Report on Climate Change: Actions to Meet Commitments Under the United Nations Framework Convention on Climate Change. By including all major greenhouse gases and their anthropogenic sources and sinks using best available science, the Report provides a practical illustration of the comprehensive approach policy to implementing the Convention's requirements. In addition to carbon dioxide emissions from fossil fuel combustion, the Report includes information on other sources and sinks for carbon dioxide, and for methane and nitrous oxide. Other gases considered include polyflourocarbons, hydroflourocarbons, and the primary tropospheric ozone precursors, nitrogen oxides and volatile organic compounds. Current Global Warming Potential indices are used to compare and integrate the best estimates of climate change impacts of the major greenhouse gases. The presentation of emission data is intended to be transparent and comparable. The relative quality of the data for various gases and sources is indicated. The existence of environmental, economic, and other benefits to limiting emissions of all greenhouse gases, in addition to carbon dioxide, should be recognized. Continuing assessments and actions on non-carbon dioxide greenhouse gas emissions, both nationally and internationally, are suggested.     

Dissolved methane in Indian freshwater reservoirs

Emission of methane (CH₄), a potent greenhouse gas, from tropical reservoirs is of interest because such reservoirs experience conducive conditions for CH₄ production through anaerobic microbial activities. It has been suggested that Indian reservoirs have the potential to emit as much as 33.5 MT of CH₄ per annum to the atmosphere. However, this estimate is based on assumptions rather than actual measurements. We present here the first data on dissolved CH₄ concentrations from eight freshwater reservoirs in India, most of which experience seasonal anaerobic conditions and CH₄ buildup in the hypolimnia. However, strong stratification prevents the CH₄-rich subsurface layers to ventilate CH₄ directly to the atmosphere, and surface water CH₄ concentrations in these reservoirs are generally quite low (0.0028–0.305 μM). Moreover, only in two small reservoirs substantial CH₄ accumulation occurred at depths shallower than the level where water is used for power generation and irrigation, and in the only case where measurements were made in the outflowing water, CH₄ concentrations were quite low. In conjunction with short periods of CH₄ accumulation and generally lower concentrations than previously assumed, our study implies that CH₄ emission from Indian reservoirs has been greatly overestimated.     

Characterizing Coral Condition Using Estimates of Three-dimensional Colony Surface Area

Coral reefs provide shoreline protection, biological diversity, fishery harvests, and tourism, all values that stem from the physically-complex coral infrastructure. Stony corals (scleractinians) construct and maintain the reef through deposition of calcium carbonate. Therefore, assessment of coral reefs requires at least some measurement endpoints that reflect the biological and physical condition of stony corals. Most monitoring programs portray coral quantity as live coral cover, which is the two-dimensional proportion of coral surface to sea floor viewed from above (planar view). The absence of the third dimension, however, limits our ability to characterize coral reef value, physiology, health and sustainability. A three-dimensional (3D) approach more realistically characterizes coral structure available as community habitat and, when combined with estimates of live coral tissue, quantifies the amount of living coral available for photosynthesis, growth and reproduction. A rapid coral survey procedure that coupled 3D coral quantification with more traditional survey measurements was developed and tested in the field. The survey procedure relied on only three underwater observations – species identification, colony size, and proportion of live tissue – made on each colony in the transect. These observations generated a variety of metrics, including several based on 3D colony surface area, that are relevant to reef management.