The transportation sector is the fastest growing energy demand in the world and it has created many economic and environmental problems for both industrial and developing countries. Economic problems, including high inflation and low developed public transport, are the main causes of the spread using of obsolete private vehicles in Iran that and this has imposed high costs on the society. In this research for estimating the social cost of obsolete cars, first of all the number of old cars in the country has been calculated and, then the social cost that old cars impose on the community have been calculated by assessing the effect of each Pollutant gas. The result shows that, in 2011, although only about 11 percent of the country’s cars were old, they cause more than 75 percent of Pollutant Emissions and this has also imposed about 32 million dollars social costs to the society. To reduce this cost, it is necessary to have a well managed integrated transport system operated by governmental and private sectors.

The present study was conducted to investigate the impacts of retrofitted CNG vehicles on air Pollutant Emissions in Tehran over a 20 years period using available statistical data, precise automobile tests, data analysis, and LEAP Software. The obtained results revealed an increase in air Pollutant Emissions including CO (equal to 1030.77 thousand tons), NOx (equal to 1030.77 thousand tons), THC (269.02 thousand tons) and CO2 (equal to 38.43 thousand tons) resulting from utilizing retrofitted CNG vehicles within the studied period. Considering the obtained results, if the current trend of producing retrofitted CNG vehicles continues, a total cost of 435 million USD will impose on the environment, annually. According to the emission test results, by implementing retrofitted CNG vehicles policy, a higher emission rate of dual-fuel vehicles will be expected compared to their petrol-fueled counterparts. This is due to poor quality of the policy implementation such the use of substandard conversion kits and old technology of retrofit technologies.

The use of biomass by means of gasification to produce bio fuels and reducing the environmental impact of fossil fuels has been the focus of many researchers in recent years. In the present study, the computational fluid dynamics method is used to predict the process of gasification inside a downdraft gasifier. Recent studies have shown that although many studies have been carried out by various researchers to maximize the cold gas efficiency in the gasification process, so far, no study has been done to minimize the emission of Pollutants as one of the other important design parameters along with the increase of cold gas efficiency. So, in this study, the effect of changing the equivalence ratio as design variable on the gasification efficiency as well as the amount of Pollutant produced simultaneously is investigated. Also, in this study, CO/CO2 and H2 /H2O molar ratios are considered as another objective function in selecting the optimal process point. In order to verify the validity of the results, the simulation data was compared with the experimental results and the previous numerical study, and a good agreement was shown between their comparison. The results of this study show that in the ratio of 0. 64, the rate of production of nitrogen oxides relative to cold gas efficiency is optimal considering the maximum production of CO/CO2 and H2/H2O molar ratios. This point is the optimal point. Under the working conditions of the gasification process.

Thermal power plants are one of the most important sources of mercury Emissions. Mercury deposition in nature has a negative implication on human health. According to Article 8 of the Minamata Convention, all parties are obliged to estimate mercury Emissions from anthropogenic sources and provide the best available control technologies. In this research, the analysis of mercury Emissions from Iran’s power sector has been illustrated using the UNEP toolkit and the STIRPAT model for the period from 2011 to 2021. The average amount of mercury Emissions and mercury emission factor were estimated as 505.6 kg and 1.85 kg/TWh respectively. The average emission factor of mercury for natural gas, heavy oil and gas oil combustion was calculated as 0.05 kg/TWh, 14 kg/TWh, and 1.29 kg/TWh respectively. The average amount of the external cost of electricity generation due to mercury Emissions was calculated as 2,616.67 US$/TWh and 5,931.11 US$/TWh in two scenarios with and without the minimum exposure threshold respectively. The results of the STIRPAT model, it was indicated that a one-percent increase in factors including population, the share of electricity generation from natural-gas consumption, and the share of electricity generation from liquid fuels consumption led to an increase of 14.83, 0.3 and 1.49 percent respectively in mercury Emissions. In addition, as a result of a one-percent increase in factors including gross national product per capita, intensity of electric energy generation and the share of electricity generation using non-fossil sources led to a decrease of 4.8, 4.74 and 0.15 percent respectively in mercury Emissions.

The members of the Cooperation Council for the Arab States of the Gulf have typically addressed water scarcity problems by building energy-intensive desalination plants. Few efforts have addressed water scarcity through metering, pricing, and other efficiency measures to reduce demand. This paper examines how decreased leakage in the water distribution system and decreased residential water use in Abu Dhabi, United Arab Emirates, could decrease air Pollutant and greenhouse gas Emissions from desalination plants. We developed a probabilistic model to predict the effects of water use reductions on Pollutant Emissions from Abu Dhabi's major independent water and power plants, which use a combination of multi-stage flash distillation and multi-effect distillation to produce fresh water from seawater drawn from the Arabian Gulf. We examine three categories of scenarios for reducing water use: increasing the price signal to residential users, instituting demand management programs among residential users, and reducing water loss in the distribution system. Our analysis suggests that water conservation price incentives could reduce air Pollutant and greenhouse gas Emissions by 1% to 5%, depending on assumptions about how households respond to the incentives. Demand-side management programs curbing per capita water use to levels typical of the Singapore or the UK would curb Emissions by 10% or 11%, respectively. Reducing water loss during distribution from the current high level of 35% to 15% (similar to loss rates in other developed nations) could cut Emissions by more than 3%. Overall, our analysis suggests that high per capita water use contributes to ambient air pollution and greenhouse gas Emissions in Abu Dhabi.

The main objective of this paper is to investigate the long-run relationship between per capita income and environmental quality indices. For this purpose, we used the CO2 Emissions and biological oxygen demand (BOD) per worker as a proxy for measurements of air and water quality. In this paper we used the Johansen's co-integrating technique for estimating the long run relationship between CO2 emission and water pollution with explanatory variables such as population density and growth rate of urban population. The results of this paper show that the EKC curve is confirmed for Iranian economy over the period of 1980 -2009. Moreover, the population density and urban population growth rate have positive and significant effect on the environmental degradation. The other results of this paper show that the elasticity of CO2 emission with respect to the population density is more than of water pollution and one percent increase in population density have led to 2.06 increases in CO2 emission.

The atmospheric impact of stack Emissions from a power plant (tri-generator and boilers) that will be installed in an urban area in the central Po valley (Northern Italy), characterized by calm wind events, is studied and compared with the impact of the existing plant (conventional boilers). Both the plants are supplied by methane gas. The atmospheric dispersion of NOx emitted is simulated, both in the current and future scenario, by the software package ARIA INDUSTRY. The NOx emission rates are set equal to the regulatory emission limits for existing and future boilers, while the tri-generation system emission rates are set equal to the emission limits certified by the system manufacturer. The simulation periods focus over the 2010 winter season. The simulation estimates the impact of NOx Emissions on air quality (vertical concentration profiles and concentration maps at the ground) in the urban area close to the plant. The future power plant impact on air quality results lower than the impact of the existing plant, even if the yearly total mass of Pollutants emitted in atmosphere from the new power plant is higher than from the existing plant. The Emissions of conventional boilers result the main responsible of the air pollution at the ground in the future scenario.

The effects of greenhouse gases (GHG) on the growth of global warming and increase of GHG and air Pollutant Emissions for energy production have prompted the need of energy recovery, which is normally wasted in industrial plants. The present research is focused on the GHG and air Pollutant Emissions reduction employing pressure waste energy recovery. Break-down pressure via Joule-Thomson valve is a neat potential for waste energy recovery in gas refineries, which may also be provided using a turbo-expander instead of commercial valves. Based on this ground, an exergy analysis is carried out for Joule-Thomson valve. The results showed that the exergy loss is higher than 6. 5 MW, and it is possible to recover about 1. 9 MW of exergy loss. On the other hand, it was found that about 16900MWh of electrical energy can be produced by recovering the energy of waste pressure, which may lead to less consumption of the load and gas in refinery power unit. Consequently, the gas consumption reduction, 12056 ton CO2e of GHG and 54. 6 ton of air Pollutant Emissions, is reduced annually. Economical evaluation of utilizing a turbo-expander, instead of a valve, proved that an alternative scenario is deductible and practical. Economical indexes, namely IRR and NPV, are found to be equal to 25. 51 % and 929571 US$, respectively. Moreover, sensitivity analysis conducted on each specific state certified the obtained results.

Background and Objective: Estimation of Emissions from wastewater treatment plant of an oil refinery is one of the issues that need to be addressed. Air Pollutants such as hydrogen sulfide and ammonia are among the most dangerous chemicals that affect personnel health and create environmental issues in industrial facilities because of their carcinogenic and toxic characteristics. The aim of this study is to estimate the amount of emission of air Pollutants to the environment. Material and Methodology: In this study, TOXCHEM software was used to estimate the emission rates from wastewater treatment plant of an oil refining company and these results were compared with the available real data from the company. Findings: Results showed that this software is able to estimate the emission rates with high accuracy. According to simulation results, about 45, 000 grams of hydrogen sulfide per day from biological treatment section and more than 50, 000 grams of ammonia per day from chemical treatment section are emitted into the atmosphere. Due to the limited capacity of wastewater treatment unit in reducing the harmful Emissions, it was concluded that the refining processes need to be improved in order to reduce the amount of air Pollutants in the wastewater sent to treatment unit. Also simulation showed that since the biological treatment section plays major role in treatment process, the control of microorganisms is required in this unit. Discussion and Conclusion: Due to high surface area of wastewater treatment unit lagoons, aeration, wind direction and turbulence, high emission rates are observed and these Emissions need to be controlled.