جستجوی مقالات مرتبط با کلیدواژه "greenhouse gas" در نشریات گروه "محیط زیست"

The aim of this study is to estimate emission of nitrous oxide gas in rice, wheat and sugarcane fields of Khuzestan using four models: DAYCENT, DNDC, YLRM and IPCC_EF. For this purpose, nitrous oxide gas precipitation was first measured. Then, using models was estimated nitrous oxide gas expansion rate. To evaluate and compare accuracy of models, statistical characteristics were used, coefficient of determination, maximum error, root mean squares error, modeling efficiency and remaining coefficient of residual mass. Release of nitrous oxide in rice cultivation in four models was estimated to be between 0.17 and 0.171. Rate of nitrous oxide emission from wheat cultivation was between 0.5-0.049 and from Shushtar station sugarcane cultivation was between -0.0371 and from Abadan station sugarcane cultivation was between 0.03-0.85. In linear regression model of rice cultivation (1.17), in IPCC_EF model, wheat cultivation (0.5) and sugarcane (3) obtained the highest amount of nitrous oxide gas per ton per hectare per year. According to results of statistical indicators for four models DAYCENT, DNDC, YLRM and IPCC_EF to estimate nitrous oxide gas were determined, respectively, the coefficient of determination (0.86, 0.94, 0.99 and 0.82), root mean squares error (0.03, 0.01, 0.85 and 0.26) and modeling efficiency (0.55, 0.94, -4.87 and -30.63).Compared to observed values, DAYCENT model for corn, DNDC model for rice, linear regression model for sugarcane cultivation of Abadan station showed good performance. Based on results of coefficient of determination, YLRM and DNDC models received the highest accuracy based on modeling efficiency of DNDC model.

Energy consumption in the country's buildings is about two to four times the average energy consumption in other countries of the world. Also in the construction sector, public and government buildings account for 70% of this energy consumption. The limited energy resources and the effects of losses on its excessive consumption make a suitable and optimal plan necessary from the perspective of energy consumption. The purpose of this study is to investigate and change the pattern of energy consumption in office buildings in order to reduce greenhouse gases. In order to perform optimization in the studied building, the amount of energy consumption and details related to the heating, cooling and lighting systems of the selected building were measured, collected and measured through field visits with the help of a luxury meter. In this study, using energy plus software, energy consumption for the building, which is in the group of buildings with high energy consumption, was simulated. It should be noted that the values ​​of energy loss, comfort level and energy consumption indicators in the building. The selection was also calculated. The results show that effective optimization measures in the building can reduce carbon dioxide emissions and reduce energy consumption by 14 to 20 percent annually. According to calculations, an average of 50% of annual energy consumption is wasted, which can be reduced to 30% by performing audit measures and thermal comfort, which is sometimes calculated to be more than 60% in certain seasons in the building increased.

Transportation has an effective role in the development and welfare of societies and is a key to economic development. Major sources of air pollutant in the oil and gas industry are: aromatic gases, vapors and dust coming out of the tower, flue gases including NH3, SOX, NOX, O2, CO2, CO. The research method is to review the life cycle assessment that provides estimating the cumulative environmental effects of all stages of the bitumen production life cycle. The results of the literature review showed that the life cycle assessment of bitumen production can be done in different ways. It can also help the organization that compare products or processes and pay attention to environmental factors in material selection. In addition, it can be useful and effective in policy‐making by helping to develop government rules with respect to the consumption of environmental resources and diffusions. The results show that in this industry, in order to move towards the development of low carbon industry, items such as observing the principles R3 (recycling, reuse, reduce), wastewater management, production of environmentally friendly product (green), use of low Power consumption systems is essential.

  Today environmental issues and avoid irregular greenhouse gas emission has become one of the most important concerns of each country. This study has been done with the aim of determining the amount of greenhouse gas emission in different industries and ranking these industries based on the most destructive greenhouse gas including carbon dioxide, carbon monoxide, Methane, Nitrous oxide, Nitrogen oxides, Sulfur dioxide and Sulfur trioxide.

In this study after identifying the most pollutant greenhouse gases based on the literature review and using the average of five recent year's data from the Iranian Statistics Center, the weight of each greenhouse gas were determined based on Shannon entropy and by using VIKOR technique and MATLAB software, the most pollutant sector was determined.

Based on Shannon entropy, Co with the weight of 0.3 has the highest coefficient of importance among pollutant greenhouse gases. Based on VIKOR technique, transportation sector based on utility measure, Vikor measure and regret measure was determined as the most pollutant sector.

 Based on the result of study, transportation sector has played a major role in greenhouse gas emissions and identified as the most pollutant sector. So, attention to structural and cultural components associated to transportation field has become more important than the past. Using green transportation technologies, investing in public transportation and providing infrastructure for non- motorized vehicles can be introduced as suggestion for reducing pollution in this sector.

There exists pollution Emissions throughout the life cycle of power plants and Life Cycle Assessment Method, as one of the environmental impact assessment, can be useful in measuring and determining the amount and source of pollution Emissions during the electricity generation process. So In line with the importance of evaluating the effects of thermal power plants, the current study with the aim of Environmental impact assessment of electricity production in Yazd Combined Cycle Power Plant is done through Life Cycle Assessment Method (LCA). For this purpose, First of all, all materials, environmental resources, technologies used and emissions of various substances into the environment were estimated in 1 MWh of electricity per functional unit (inventory). Finally the impact of each of these inputs in the form of environmental indicators, were Quantitized. In this study we evaluated the environmental impact of electricity generation using Simapro8 software and CLM2000 evaluation method in 10 floors of potential effects. The results showed that the production of one megawatt hours of electricity in Yazd Combined Cycle Power Plant has a significant environmental impact In terms of offshore aquatic toxicity, acidification, depletion of fossil fuels and global warming. According to obtained information fossil fuels have created the most negative environmental impacts among other inputs. Global warming potential over the life cycle to producing 1 MWh of electricity in power plant of Yazd, In the process of operation of power plant using 623 kg And in the construction phase ./54 kilograms of carbon dioxide equivalent emissions were calculated.

Greenhouse gas emission and distractive environmental crisis such as global warming and change climate was occurred by human activation in natural ecosystems in this century. Due to this problem carbon sequestration is a win-win approach to purpose reducing of distractive human activation and emission of greenhouse gas. Accordingly, this study was carried out to purpose the assessment of carbon sequestration with economic value by Quercus brantii Lindi forest in Kermanshah province in 2015 to 2016.
Essential data for this research was collected by on farm method and random sampling method in two groups including coppice and single stem forms in oak forest in Bisetoon protected region. Then, the amount of carbon sequestration and its economic value were calculated by using the collected data and application of mathematical relations in this forests.
According to result of this study amount of carbon sequestration by trees biomass was 1622.67kgha-1yer-1 in coppice forms. This amount was 1786.47kgha-1yer-1in single stem. Therefore amount of CO2 captured and saved in wood tissue and organic matter of residual in bottom of tree layer was 5841.61, and 6431.29 kgha-1yer-1 in coppice and single stem forms. Due to the applied tax rate for every ton of carbon emissions, the annual economic value per hectare of this forest was estimated 1780856 rials.
furthermore, suitable management of oak forest ecosystems in this investigating region and subsequently around the country is very important to purpose of reduces the environmental crisis, such as reducing greenhouse gas emissions and change climate. On the other hand, Due to the importance of carbon credit issue and international issues surrounding it, it has benefited for the resumption and maintenance of these natural ecosystems.

Nowadays, increase of energy consumption in agricultural section has lead to some environmental problems and increase of final costs. In this study, the non-parametric method of Data Envelopment Analysis (DEA) is used to estimate the energy efficiency and greenhose gas emission in the irrigated wheat farms in Silakhor plain of Lorestan province.
Data were collected through both questionnaire and interwiew surveys using 150 farmers. Results showed that the energy consumption for 0.1 up to 2, 2.1 up to 5 and over 5 hectares were 22134, 24128 and 25078 MJ/ha respectively, and the sum of grain, fertilizer and pesticides had the highest share of energy consumption in all levels. The results of DEA showed that technical, pure technical and scale efficiencies in the third level were 88, 93 and 94%and higher than the same amounts obtained in other levels.
Energy saving ratios in these levels were 6.83, 8.11 and 6.54 respectively. This indicates that 1512, 1957 and 1640 MJ/ha of total input energy can be saved, if the mentioned method is used. The results of greenhouse gas emission showed that diesel fuel has the highest share in the environmental pollutants. Optimization of energy consumption can totally decrease 6516.67 kg CO2 produced in wheat production.

Stand-alone solar LED lighting solutions illuminate small and large trails as well as parking lots and recreational shelters located in areas too expensive or sensitive to run power lines. Since the energy is valuable, solar park lights can save cost over traditional park lights when installed in new or existing parks. Solar lighting systems are easy to install and include cost saving options of Connection to the grid, produce fewer greenhouse gases and desired light levels. In this study, 50 solar lamp bases are designed and lights were installed on campus. For economic and environmental assessment lights RET Screen software was used. The RET Screen International Clean Energy Decision Support Centre seeks to build the capacity of planners, decision-makers and industry to implement renewable energy, cogeneration and energy efficiency projects. Based on the results, the internal rate of return equals to 37/3 % and the simple payback time equals to 8/2 years, and the equity payback time equals to 4 years and during this period, 6.9 tons of greenhouse gas emissions has been avoided.

A landfill is a location designed for systematic long-term storage of waste under the conditions that it will prevent contamination of air and water. Landfill gas is produced by bacterial decomposition, which occurs when organic waste is broken down by the bacteria naturally present in the waste and in the soil used to cover the landfill. Landfill gas is composed of a mixture of hundreds of different gases. By volume, in general the landfill gas typically contains 45% to 60% methane and 40% to 60% carbon dioxide. This study has estimated total produced gas, carbon dioxide and methane, by the basic first-order decay model for Aradkooh Landfill till the next 30 years after the landfill is closed. Gas production has decreasing trend in time, as the maximum gas production for methane and carbon dioxide is in order of 6 and it will be 16 million kg in the year 2015. The minimum contribution will also be in order of 0. 3 and 0. 8 million kg in 2044. The total produced gas in the 30 years is 213 million m3 which 27% of its mass belongs to methane and 73% is carbon dioxide gas. In addition, the amount of methane, carbon dioxide and sulfur dioxide contributed from energy generation technology is calculated for 30 years and compared. The results show that the emission rate of controlled carbon dioxide gas is 1. 85 times in uncontrolled state and the emission of controlled methane gas is 0. 15 in uncontrolled state. In addition, using energy generation technology leads to sulfur dioxide contribution. The estimation for total amount of this gas in 30 years is predicted about 361 kg. Finally, the gases emissions predicted from this model are validated using the mass balance method according to other studies. Comparison of results shows good agreement with other studies. Industrialization, along with economic growth, results in an increase in production of municipal solid waste (MSW). Landfills are managed by a simple landfill method, and it creates secondary pollution such as water pollution by leachate, leakage of gases, and bad odors. LFG consists of 50–60 vol% CH4 and 30–40 vol% CO2 with numerous chemical compounds such as aromatics, chlorinated organic compounds, and sulfur compounds. CH4 and CO2, both greenhouse gases (GHGs), contribute to global warming. CH4, in particular, is a very potent greenhouse gas which is almost 21- 25 times more powerful than CO2. However, it is a green fuel which can be used for electricity generation. The most common disposal method for municipal solid wastes (MSW) is burial in landfills since the usage of intermediate treatments such as incineration, pyrolysis, and recycles are not actively practiced to effectively remove the wastes (in Korea). According to various studies, a total of 40–60 Mtonnes of CH4 is emitted from landfills and old waste deposits worldwide, accounting for approximately 11–12% of the global anthropogenic CH4 emissions. This ranks landfills third after rice paddies (60 Mtonnes/year) and ruminant livestock (85 Mtonnes/year). Shin and his colleagues (2005) assess different gas-to-energy technology with landfill gas and analyze and compare emission rates of each technology using LEAP model. Jaramillo and Mathews (2005) presented formulas for calculating emission rates of CH4،CO2 وSO2 based on landfill gas emission rates and compared emission of controlling landfill gas technologies such as flares, IC engines, gas turbine and steam turbine. In this study, emission rates of different gases such as CO2 and CH4 in MSW landfill located in south of Tehran will be calculated in different elapsed time from burial of waste using equations and formulas. The influence of using LFG controlling technologies on emission reduction will also be discussed. When a landfill-gas-to-energy project is designed, one of the most important factors to be considered is the amount of gas available to generate the electricity. Landfill gas starts being generated shortly after the landfill begins accepting waste and it can last for up to 30 years after the landfill closure. The production of landfill gas generated in year T given previous disposal of waste at time x (in millions of cubic meter per year) can be estimated from a basic first-order decay model: LFGT, x=2KRxL0e-K (T-x) Where, 2 is the ratio of landfill gas to methane; K is the rate of methane generation (1/yr); Rx is the amount of waste disposed in year x (kg); L0 is the total methane generation potential of the waste and x is the year of waste input (m3/kg). The total landfill gas generated (LFGT) in a year by all the waste in the landfill is the sum of LFGT, x across all values of Rx. k depends on the climate of the area where the landfill is located. EPA recommended value for wet climate is 0. 225/yr. For medium moisture and dry climates, EPA recommends values of K are 0. 1/yr and 0. 06/yr. Municipal landfills have the potential to emit large quantities of methane and carbon dioxide, as well as some non-methane organic compounds. Under the 1996 New Performance Standards for Municipal Landfills, large landfills have to control these emissions. Flaring has been traditionally used as the control method. Methane emission control can also be achieved by using electricity-generating equipment. It is important to note that both flaring and electricity-generating equipment create emissions of criteria pollutants such as NOx, CO, SO2, and particulate matter (PM). To perform a more socially relevant analysis, valuation of emissions (greenhouse gases and criteria pollutants) was included for this project. Equations were used to calculate these emissions and were developed by use of the AP-42 emission factors for municipal solid waste landfills. For any given landfill, the costs of net emissions from a landfill gas-to-energy project were compared with the current net emission costs at the landfill. For a landfill where a collection/flaring system is not present, current emissions are uncontrolled (U) methane and CO2 emissions, as calculated by: UCO2 = (0. 5) (1. 794) (LFGT) Where, 0. 5 is the assumed percentage of landfill gas that is CO2. 1. 794 is the amount of CO2 (kg/m3LFG), and LFGT is the total amount of landfill gas generated in year T (m3) UCH4= (0. 5) (0. 6567) (LFGT) Where, 0. 5 is the assumed percentage of landfill gas that is CH4, and 0. 6567 is the amount of CH4 (kilogram per cubic meter of landfill gas). The results obtained from this model are validated using the mass balance approach. Due to this method, the maximum amount of LFG generated in the anaerobic decomposition can be estimated by the following simplified reaction: C6H10O4 (waste) + 1. 4H2O → 3. 25CH4 + 2. 75CO2 In landfills where a collection and flaring system is in place, emissions are those from a flaring system. In this case, the uncontrolled methane is converted into emissions of CO2 (combustion efficiency was assumed to be 100%) and criteria pollutants. Equations are used to calculate controlled (C) emissions of CO2, CH4. Collection efficiency (ηcol) is assumed to be 85%. Where, 2. 75 is the ratio of the molecular weight of CO2 to the molecular weight of CH4. The equations are also valid for CH4, CO2, and SO2 emissions from internal combustion engines, gas turbines, and steam turbines, where methane combustion is also assumed to be 100% efficient. It is predicted that according to capacity of the landfill and daily volume of burial waste, Aradkooh landfill will be closed in 2015 to emit gas. The emission of uncontrolled CH4 and CO2 were calculated in 30 years. According to the calculation, the maximum volume of landfill gas emission will be 18 Mm3 in 2015. And minimum volume of LFG emission will be approximately 0. 9 Mm3 after 30 years. The maximum and minimum mass of uncontrolled CH4 will be approximately 6 Mkg in 2015 and 0. 3 Mkg in 2044, respectively. Deceasing rate of CH4emission is slower in comparison with landfill gas emission. Emission rate of contaminant gases like CH4 and CO2 in presence of landfill gas-to-energy technologies such as IC engine, gas turbine and steam turbine in next 30 years were calculated. It is predicted that maximum volume of controlled CH4 will be 0. 85 Mkg in 2015. After 30 years this mass will be decreased approximately up to 0. 3 Mkg. Incomplete combustion in each of CH4 molecules after combusting in gas-to-energy facilities will be altered to 1 CO2 molecule and 2 H2O molecules. So the emission of CO2 in state of using gas controlling technology will become more than emission of uncontrolled CO2. Emission rate of uncontrolled CH4 is approximately 6 times more than emission rate of CH4 in presence of landfill gas-to-energy facilities. The emission rate of CO2 in state of using landfill gas-to-energy facilities are 1. 85 times more than emission rate of uncontrolled CO2. This increase is the result of altering CH4 into CO2 in state of using landfill gas-to-energy facilities. Controlled CH4 emission rate is 0. 15 of uncontrolled CH4 emission rate. Considering that CH4 global warming effects is approximately 25% more than CO2, it can be concluded that using landfill gas-to-energy has a significant impact on reducing global warming. It is predicted and estimated that maximum methane and carbon dioxide emitted from Aradkooh landfill will be approximately 6 and 16 Mkg in 2015 and minimum mass of methane and carbon dioxide emission will be 0. 3 and 0. 8Mkg after 30 years in 2044. Total gas emission in 30 years will be 213 Mm3. %27 of total mass of landfill gas is methane and %73 of total emitted gas from landfill is carbon dioxide. Using landfill gas-to-energy technologies causes SO2 emission. The amount of SO2 emitted from Aradkooh landfill will be approximately 361 kg in 30 years.

After power stations, transportation section, especially road traffic, is known as the most important cause of climate change. In the transportation literature these costs, known as the external costs, are not paid by people who cause them. Conversely, based on the economic welfare theory, any cost that takes place in society must be paid by people who cause it. So these costs must be recognized to be converted into the monetary value. The values, then, must be taken by charges or other ways taxes. In Iran, there is no research that relates to the issue of external cost of climate change. Therefore, there is no monetary value of climate change costs due to road transportation in Iran yet. In this paper, this research gap is considered and a mathematical model is used to estimate the mentioned costs. The results are obtained for different vehicles in road transportation including car, mini bus, bus, truck and other vehicles. The model is run for freeways in Iran. The results of the model indicate that external costs of global warming are 10.3, 31.3, 94, 94 and 135.8 Rials for 1 Km mileage of each passenger car & pickup, mini bus & light truck, two and three axle trucks, bus and heavy trucks, respectively. Annual external cost of CO2 emission in freeways is also approximately 360 billion Rials, 30% of which is the contribution of heavy trucks, passenger cars & pickup take the second place with the share of 25%. The results of this paper can certainly help the policymakers to make good, precise and fair decisions related to the charges of road transportation. Road transportation, primarily, due to its unique characteristics have a special position among various transportation modes. Road transportation is the most available and easy to use mode of transport in Iran. But the transportation has negative impacts too. Road transportation activity imposes external costs such as air pollution costs, noise costs, climate change costs and etc. What should be considered in external costs is that the contribution of the road transport, as international studies show, is around 92% of total external costs of the transport sector. Climate change or global warming is one of the major threats to humanity in the 21th century. After energy section, transportation section especially road transportation, is known as the most important cause of climate change. In the transportation literature these costs, known as the external costs, are not paid by people who cause them. Conversely, based on the economic welfare theory, any cost that takes place in society must be paid by people who cause it. These costs cause loss of a considerable amount of public resources. For example, the external costs for 17 European countries for year 1995 have been around 975 billion dollars. This costs has been estimated around 600 billion dollars for US in 1989. So, these costs must be recognized to be converted into monetary value and then these costs must be taken by charges or other ways of road pricing. This paper is based on a theoretical-practical research which deals with one of the major challenges of the present transportation by employing quantitative techniques and statistical and econometrics models. In Iran, there is no research that relates to an issue of external cost of climate change. Therefore, there is no monetary value of climate change costs in Iran yet. Unfortunately, the government is not attentive to external costs; although the topic has been highlighted in recent years and some studies have been conducted regarding the subject. Yet, these costs are not considered in economical transactions. In this paper, this research gap is considered and a mathematical model is used to estimate the costs of climate change. The results are obtained for different vehicles in road transportation including passenger car and pickup, mini bus, bus, two and three axles truck and heavy truck. The model is run for Expressways in Iran and results are demonstrated. Estimation of some of the parameters existing in the model would take a long time and require a much budget. So, these parameters were extracted from the literature. To estimate the global warming costs, a simple model from GRACE project has been adopted. Table 1 shows more details of the mentioned model. The required data for this model has been prepared. These data items include price of 1 tone of Co2, amount of Co2 released by each vehicle type and amount of Co2 released from fuel production. External costs of global warming are estimated for expressway network of Iran based on the model presented in previous paragraph and in Table 1. The first step of this phase is to select a representative sample of Iran's expressways. Totally 13 expressways were selected. It was tried to select a sample representative of Iran’s expressway network to facilitate generalization of the results. In the next step, a lot of information regarding the selected roads (including length of road, daily traffic volume, statistics of vehicle types, and etc.) from different data sources has been collected, aiming at using this information in appropriately in the model. In addition, vehicles have been classified in five main classes. After gathering the required information, the model was employed and the external costs of global warming have been estimated corresponding to different types of vehicles. Discussion and The values in above table have a straightforward interpretation. As an example, a user of passenger car or a pickup must pay 10.3 Rials passing 1 KM of expressway as a compensation of global warming external costs. This value is 135.8 and 94 for heavy trucks and buses, respectively. The results indicate that annual external cost of co2 emission in Expressways is approximately 360 billion Rials, 30% of which is the contribution of heavy trucks with more than 3 axles followed by passenger cars and pickups with the share of 25%. The considerable amount of these external costs is a good index to realize the importance of external costs of Iran’s road transport. It should be noted that these costs are different from many non-monetary effects which external costs impose to society. This involves careful attention of governors and macro-level decision makers to external costs and their issues to provide appropriate solutions to reduce or internalize these costs. It should be noted that the main and most important solution to reduce and manage external costs is road pricing and charging road users. The experience of this solution in the world has shown that besides reducing external costs, a considerable financial resources is gathered from user charging, which can be used in more transportation infrastructure developments. The results of this paper can certainly help the policymakers to make good, precise and fair decisions related to the charges of road transportation.