مظاهر معین الدینی

Given the current industrial development, the footprint of chemical production’s environmental toxicity is increasing. The toxicity footprint depends on the environmental conditions and the time of poisoning agents’ entry into the environment, as well as the properties of the substance released in terrestrial and aquatic (fresh and salty) ecosystems. In environmental management, a comprehensive understanding of the toxicity footprint and its causes is of paramount importance. Using life-cycle assessment, the toxicity footprint may be studied comprehensively and integratedly and based on the life cycle perspective, resulting in the identification of the most important life cycle components and stages affecting it. The present study was aimed at investigating the toxicity footprint of methanol production severally by utility and process units in terrestrial and aquatic ecosystems by the life-cycle assessment method. Identification and quantification of the toxicity footprint severally by process and utility units would contribute to better recognizing the methanol production unit’s situation. By determining the necessary priorities, the plan of reducing the footprint of the product could be initiated. The system boundary was gate to gate of methanol production from natural gas.

The functional unit in this study was one thousand tons of methanol production.

According to the current study results, compared to the utility units, the process units were more effective in the toxicity footprint of terrestrial ecosystems, freshwater, and seawater.

The rate of toxicity footprint associated with process units in terrestrial ecosystems, fresh water, and seawater was 96.3%, 77.3%, and 76.4%, respectively.

The aim of this study is to develop a comprehensive model of the urban waste management system to compare different waste management scenarios. For this reason, a comprehensive model was developed using a system dynamics approach. Additionally, the life cycle impact assessment method based on endpoint was used to compare the various waste management scenarios. The validation results for population changes and waste generation indicated excellent predictive value for the model. The results showed that the amount of waste generation is increasing during the simulation period and the volume of landfilled waste in all scenarios is greater than the remaining capacity of the landfill in the study area. The BAU scenario showed the worst situation in terms of environmental indicators, so that during the simulation period, the amount of landfillable waste and net greenhouse gas emissions (in terms of carbon dioxide equivalent) reached 21.7 and 10 million tons, respectively. Also, the environmental damage cost due to waste landfilling during the simulation period has also reached $567 million. In contrast, organic waste management through anaerobic digestion and composting significantly improved the system's performance in terms of environmental indicators. In the anaerobic digestion scenario, the amount of waste landfilled, net greenhouse gas emissions, and environmental damage costs decreased by 66%, 269%, and 54%, respectively, compared to the BAU scenario. This study demonstrated that the system dynamics modeling approach can provide a comprehensive view of the waste management system and test various policies and strategies for sustainable waste management.

The aim of this study is to develop a comprehensive model of the urban waste management system to compare different waste management scenarios. For this reason, a comprehensive model was developed using a system dynamics approach. Additionally, the life cycle impact assessment method based on endpoint was used to compare the various waste management scenarios. The validation results for population changes and waste generation indicated excellent predictive value for the model. The results showed that the amount of waste generation is increasing during the simulation period and the volume of landfilled waste in all scenarios is greater than the remaining capacity of the landfill in the study area. The BAU scenario showed the worst situation in terms of environmental indicators, so that during the simulation period, the amount of landfillable waste and net greenhouse gas emissions (in terms of carbon dioxide equivalent) reached 21.7 and 10 million tons, respectively. Also, the environmental damage cost due to waste landfilling during the simulation period has also reached $567 million. In contrast, organic waste management through anaerobic digestion and composting significantly improved the system's performance in terms of environmental indicators. In the anaerobic digestion scenario, the amount of waste landfilled, net greenhouse gas emissions, and environmental damage costs decreased by 66%, 269%, and 54%, respectively, compared to the BAU scenario. This study demonstrated that the system dynamics modeling approach can provide a comprehensive view of the waste management system and test various policies and strategies for sustainable waste management.

In this study, the main sources of hydrocarbon emissions in the atmospheric deposition of Mashhad megacity were investigated.

For this purpose, the compounds of PAHs, n-alkanes, hopanes and steranes were investigated and the source of hydrocarbon emissions with particulate matter (PM) was determined using diagnostic ratios and principal component analysis (PCA). Thirty atmospheric deposition samples were sampled in the winter season in 2018.

The mean concentrations of compounds in atmospheric deposition samples were 1575/12 ng/g for PAHs, 2299.9 for n-alkanes, 2208.6 μg/g for hopanes and 298.2 μg/g for steranes. The most abundant PAHs in atmospheric deposition were four- and five-rings hydrocarbons. On the other hand, the most abundant n-alkanes (n-C20 and n-C22) demonstrated anthropogenic (pyrogenic) source. Moreover, the presence of hopanes and steranes biomarkers confirmed the pyrogenic source (present in vehicle exhaust particles) in the studied samples. In all samples, the presence of unresolved complex mixture (UCM), carbon preference index (CPI) close to 1, diagnostic ratios of PAHs and ratios of hopanes and steranes, indicating the predominant pyrogenic source for hydrocarbons were obtained. In this study, the PCA results for atmospheric deposition samples demonstrated two factors including emissions from diesel and gasoline engines, as well as the burning of biomass and fossil fuels, such as natural gas. Moreover, two factors were obtained for n-alkanes. The first factor exhibited the contribution of burning fossil fuels, especially emissions from automobiles. The second factor was related to emissions from biogenic sources. The PCA results for PAHs and n-alkanes were consistent with the diagnostic ratios approach and, the PCA results confirmed the consequences of diagnostic ratios.

The results from both methods exhibited that the highest contribution to the emission of these compounds is related to pyrogenic sources, especially traffic, which had a higher proportion of emissions from vehicle exhaust.

Identiying the most optimal solution has long been an significant challenge for waste management decision-makers. This study aims to develop a decision support system to identify optimal environmental and economic scenarios for waste management.

This study presents the development and application of a decision support system that estimates the environmental burden and cost of waste using Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) tools. The system then identifies optimal environmental and economic scenarios for waste management through a linear programming model. Data from the Karaj waste management system were utilized to apply and validate the decision support system.

The outputs of the linear programming model in this system included one scenario based on minimizing environmental impacts and two scenarios based on minimizing costs imposed on the Karaj waste management system (MSWS). In both the environmental and second economic scenarios, incineration contributed the most to waste management, whereas composting was the dominant method in the first economic scenario. Additionally, recycling the maximum possible amount of recyclable materials was a common feature in all three scenarios, due to its environmental and economic benefits.

The result of this study demonstrate that the current Decision Support System can provide optimal environmental and economic scenarios for waste management to the decision-makers in the field. This is achieved by considering the inherent differences in the types of waste produced, the technologies employed, and the processing costs associated with each waste management system.

In light of the close interrelation of water, energy, and food resources, the water-energy-food nexus will establish a robust framework for sustainable management. This study examines the legal framework of the country's proposed seventh development plan, employing a thorough analysis of the water-energy-food governance system. The findings highlight crucial aspects in the plan's execution. For this investigation, we identified 34 obligated entities and 54 legal responsibilities outlined in the seventh development plan of the country. Network collaboration analysis was performed using Ucinet and Netdraw software. The results revealed that the highest levels of degree centrality (0.60), betweenness centrality (0.33), and closeness centrality (0.159) belong to the Ministry of Agriculture. The density of the network was about 13%, which shows that the cooperation network in the seventh development plan is completely separated. The average geodesic distance was 2.079, so strengthening cooperation in the network is needed, despite the Ministry of Agriculture and the Ministry of Energy having the highest power, there was a significant distance between them, with the Department of Environmental situated between these two entities. The Ministry of Agriculture, the Ministry of Energy, the Administrative and Recruitment Organization, and the private sector were pivotal points in the collaboration network. In the governance structure of power distribution, the Ministry of Agriculture held the highest power. The results demonstrated that in the governance structure, little attention was paid to the water-energy-food nexus. Therefore, in line with sustainable management policies, the government's power and the Department of Environment's position should be strengthened.

One of the largest sources of methane emissions is landfills, and various models have been developed to predict landfill methane production and emissions. The main goal of this research is to utilize the inverse Gaussian model to estimate g methane greenhouse gas emissions and model it using field data. This study introduces a simple method to estimate the amount of methane emissions based on ambient methane concentrations.

In this research, the methane emission rates from landfill were estimated for warm (July) and cold (February) seasons using a sampling campaign from 27 stations and standard inverse Gaussian dispersion equations. Monte Carlo simulation was also employed. To determine the model, an optimization-based method, along with inverse scattering modeling, was utilized to process surface emission monitoring data.

The model results indicated during the cold (February) and warm (July) seasons, the methane emission rates were estimated at 1696.99 and 16.53 g/s, respectively. These findings confirm that the methane production and emission during the cold season were lower than in the warm season, likely due to reduced temperature and bacterial activity.

The method used in this study, the inverse Gaussian dispersion model, can be applied to estimate methane gas emission rates from other landfills. However, it necessitates the permanent recording of data and the use of daily or weekly averages in calculations to mitigate potential errors and enhance the accuracy of modeling.

Today, one of the most important issues related to human development is climate change. Due to the increasing trend of production and consumption of polymer products, the emission of greenhouse gases has increased in this sector and it is necessary to take effective measures to reduce the consequences of climate change. The aim of this study is to evaluate the effectiveness of greenhouse gas emission reduction scenarios in an integrated manner based on Net Zero guidelines. In this research, using the guidelines of Net Zero (combustion emission, per energy and material consumption) and the concept of carbon intensity of emission equivalent to carbon dioxide, the effectiveness of greenhouse gas emission reduction scenarios for the production of one ton of polyethylene has been evaluated. According to the results obtained in this research, the most effective scenarios are replacement with photovoltaic energy source, which reduces greenhouse gas emissions by 0.7% (5% replacement) to 6.3% (50% replacement). Also, electricity saving scenarios from 5% to 20%, in three scenarios with 5%, 10% and 20% electricity savings, which will reduce greenhouse gas emissions by 0.6% to 2.6%. On the other hand, the plan to recover combustible gases in the polyethylene production process, according to the available technologies, can contribute to the reduction of greenhouse gas emissions by 1.2%. In general, it can be stated that the recovery of combustible gases is more reasonable than costly scenarios such as replacing the energy source.

The economic evaluation is a tool for decision-making based on data that helps to select and prioritize waste management components and their implementation based on economic criteria. The purpose of this study was a comprehensive economic evaluation of the waste management components by life cycle costing assessment (LCC) , Net Present Value index (NPV), and Internal Rate of Return (IRR).

The cost of each waste management component, was calculated by LCC for one tonne of waste in. The efficiency of each waste management component was obtained using the NPV and IRR indicators.

The results showed that recycling with 260%, and then composting with 40%, have the highest economic returns and the ability to return capital. The sensitivity analysis showed the profitability of these two processes despite the changes of ±30% in the influential calculation parameters.

In this study, comprehensive economic evaluation showed that using LCC, NPV, and IRR with their sensitivity analysis, simultaneity can have an important role in waste management decision-making.

Considering the worn-out public transport fleet in Karaj city, it needs to replace the fleet with up-to-date standards. Considering the economic and environmental dimensions, the effectiveness of the measures taken should be evaluated. Therefore, achieving the goal of evaluating the change in the emission of pollutants based on each alternative scenario can help the authorities to adopt air pollution reduction strategies. The purpose of designing scenarios in this research is to estimate the effectiveness of scenarios in the field of replacing the fleet of worn-out single buses in reducing the emission of air pollutants.
Material and First, the classification of buses and units based on parameters such as different systems, year of production, pollution standard, type of fuel consumed and vehicle class have been studied at 1398. Then, scenarios of reducing standard pollutants were designed in two plans, replacing the worn-out fleet with a hybrid fleet, dual-fuel and with fuel consumption, with Euro 4 pollution standard, and finally the scenarios were compared with the basic scenario. Pollution emission coefficients and scenario design were calculated using the International Model of Mobile Vehicle Emission (IVE) model for passages, 1st degree arteries, highways and freeways, with slopes of zero and 22%.
The results of comparing the scenarios showed that by replacing the entire worn-out fleet in terms of age (to the new fleet, scenario four), the maximum reduction in emissions of standard pollutants was 40% (CO, 60% (VOC), 42% (NOX), 86% (Also, the results of the distribution of pollutants in the city of Karaj, with Arc Map software showed that the highest emission of pollutants is related to region 10, and the lowest emission is in region 1, Karaj city.
Discussion and According to the findings, the effectiveness of replacement scenarios of the worn-out fleet (use of hybrid, dual-fuel vehicles with Euro 4 fuel) in reducing the emission of air pollutants has been 40 to 80%. Pollutant reduction scenarios and strategies to increase air quality are useful for policymakers and researchers to better understand the current state of air pollution in the region and are largely operational, requiring timely funding and well-planned planning.

Due to the environmental problems caused by wind erosion, it is necessary to stabilize the dust centers with mulches. The objective of the present study was to determine and compare the optimum vinasse mulches based on mechanical indicators for sensitive soil stabilization to wind erosion. In this research, vinasse (0, 100, 200 g) is combined with bagasse (0, 25, 50 g), ash bagasse (0, 25, 50 g), filtercake (0, 12.5, 25 g), and one-liter water (81 treatments). At first, the treatments were determined in the appropriate range of salinity and acidity (35 treatments) and in the next step, the mechanical indicators have been measured after mulching on laboratory trays (2×30×100 cm). Optimum mulches have been determined based on five indicators by mean comparison (Duncan). The mean comparison showed that treatments 33, 30, 34, 32, and 19 show the mean difference between the groups based on layer thickness, impact resistance, compressive strength, and shear strength properly. It can be concluded that vinasse (100 and 200 g) with 50 g bagasse reduces the crack coefficient greatly, and the application of vinasse, bagasse, and filtercake does not affect the compressive strength and impact resistance.

Population growth with the growth of urban communities has been increased consumer demand and waste production. Waste collection and transportation, as the most expensive element in the waste management system, is so important that a slight change in the cost of management process will reduce the related costs in the waste management system. Among these, transfer stations, as facilities that reduce the costs of collection and transportation, are particular importance. The aim of this study is to select a suitable site for the construction of a waste transfer station and then prioritize suitable options in Karaj. The innovation of this research is in the number of criteria and sub-criteria used for locating and prioritizing options. After setting the major criteria and sub-criteria related to the location of the waste transfer station in this city, their maps were prepared. A total of 3 criteria and 14 sub-criteria were used in this study, then the prepared maps were standardized to a range of [0, 1] and the weight of each criterion and sub-criterion was determined using the pairwise comparison method. The weighted linear combination method was used to prepare the suitability map. The results showed that the major criteria for choosing the transfer station were the boundaries and distances, followed by the physical criteria of land and land use. Then 10 options were selected as the final option and 2 criteria of future development plans and land price were also added to the research and the options were prioritized using the TOPSIS method and the most suitable option with an area of more than 4 hectares was selected in 4 regions. The approach used in this research can be used in other cities.

The purpose of the study is to investigate how urban environmental management in the district 22 of Tehran in order to provide a comprehensive model and improve it. The research is applied in terms of purpose and analytical-descriptive in terms of method, so in collecting data from internal and external sources and in the survey phase, 20 elite expert managers in the field of bio-urban management were used through a questionnaire. Executive model of strategic research planning derived from individual Fred.R.David `s strategic management model and the QSPM matrix was used to execute the decision making process. Presenting a comprehensive and environmental model with the environment of the 22nd district of Tehran municipality, which is capable of determining the weak points of urban management and providing a solution to improve it, is one of the innovations of this article. According to the findings of the research and the final score of less than 2.5 determined in the environmental management of the municipality of district 22 of Tehran, the strengths and opportunities obtained to overcome the disadvantages and threats have not been properly used and the type of strategy, defensive. The results showed that three strategies, “Evaluation of Areas Requiring Protection”, “Reforming Legal and Organizational backgrounds, Reforming Organizational Structure and Integrated Urban Management are the most important Promotion strategies for urban management.

The dust storm is recognized as a global problem which has a large-scale negative impact on the world. Dust strong winds transport them long distances. The dust storm caused a lot of damage to the economy, health and the environment. Therefore, an adequate understanding of the origin and time of dust storms can be effective in reducing dust damage. The purpose of the ongoing research is to identify the source of the dust storm events. For this purpose, the dust events in a period of 11 years were analyzed using the synoptic meteorological data of Kermanshah. The number of 646 dust storms were identified, and their detection operations and identifying of the areas affected by dust storm and areas of origin were performed using MODIS and Deep Blue. The HYSPLIT was used to route the dust storm and the entry routes of dust storm into the Kermanshah city. Based on the dust codes, the highest number of dust storms per year was registered in 2008 and 2009, respectively.  Most dust storms were observed in summer and during May, June and January. The results of DRS, HYSPLIT have shown that the western directions have the largest amount of dust input in Kermanshah, and the MODIS and Deep Blue images also confirm this fact. Overall, the findings showed that most of the routes come from the north and centre of Iraq and the Syrian Desert.  Dust storms originate at the border and arid lands of northern and central Iraq and Syria.

Fossil fuels, due to limited resources, causing pollution and global warming, have caused the use of renewable energy, especially wind energy, to be considered. For this reason, to determine the criteria for locating wind farms in the coastal area of Sistan and Baluchistan province, from reviewing the sources, studying the plans and research, standards, and reviewing documents from 30 internal sources 20-year ago and external sources was used. Due to a large number of criteria and indicators, summarization was done, they were divided into two ecological and human groups, which include 8 criteria, climate, land, uses and management areas, development infrastructure, capital resources, Itis management, health and consequence, the average wind speed and distance from the residence had the highest frequency of indicators in previous experiences. The Delphi method was used to screen the criteria and the opinions of 11 wind farm experts were used. The results of the content validity evaluation of the questionnaires showed that all the respondents chose the indicators of average wind speed, wind continuity, distance from landslide areas, distance from military operation areas, distance from the power grid, and development costs as the most important spatial indicators. Measuring the importance of the criteria based on the Delphi method is dependent on the calculation of two indicators, the percentage of importance and the degree of importance, which were used to calculate the final importance coefficient of the criteria through these two parameters. Based on Delphi calculations, the most essential site selection wind farm indicators were obtained, respectively, average wind speed, wind continuity, distance from the power grid, and wind power density. In order to evaluate the potential of wind energy for the development of wind farms in the coastal area, climate indicators, annual average wind speed, annual average wind power density, and annual average wind continuity percentage were used. Analysis of climatic criteria was done by using a geographic information system and kriging interpolation functions of mapping. Finally, the coastal area was divided into two zones, 91% suitable for wind power development and 9% unsuitable.

Ports are involved in transferring more than 80% of materials and goods. With life cycle assessment, all environmental impacts are assessed simultaneously and this method has not been implemented for non-container ports. The goal of the study is life cycle assessment of liquid, gas, container, bulk, and tanker loading in the port to define the most impactful sub-processes in the port operations. Life cycle assessment is done from the source of production to the port (scope 1) and from the gate of the port to loading to ships (scope 2). One MMt of loading material is considered as functional unit. The results of the study showed that the impacts of scope 1 are far lower than scope 2 and it is worth focusing on scope 2 for any environmental improvements. In the global warming impact, gas loading has the highest share of 35%, of which 50% is due to electricity, and 45% is due to flaring. Bulk loading with a share of 30% entirely due to electricity is the second. Liquid loading with a share of 20% has the third rank as a result of electricity by 95%. It can be seen that in all sub-processes, electricity has a major role in all impact categories. In port operation LCA, per each MMt of total loading, bulk, liquid, and gas loading have the highest share over 18 impact categories to different extents. It is suggested to develop improving scenarios focused on electricity consumption, considering renewable energy sources, and no flaring for the port.

Some heavy metals in the air are very important due to their biomagnification properties, persistence and harmful effects on human health. The main goal of this research is to identify and assess the risk of heavy metals that have carcinogenic and non-carcinogenic potential for the people of Region 21.

District 21 of Tehran was selected as the study area due to its industrial and semi-industrial uses. According to ASTM and EPA standards, 50 air samples were taken from different uses of Region 21 in 2021 using high volume pumps with the help of fiberglass filters. The concentration of heavy metals was determined using ICP-OES. Cancer and non-cancer risk assessments were also calculated using the IRIS integrated information system method.

The average concentration of heavy metals in the decreasing trend is Li <Ti <W <Pb <Sr <Mg <Fe <Zn <Cr <Al, respectively, with aluminum having the highest concentration of 58.87 µg/m3 and lithium with 0.01 µg/m3 has the lowest concentration. In addition, the results of respiratory risk assessment indicate that HQ aluminum with 1/13E+01 has a non-cancer risk and Cr lead with 1/49E-05 has a cancer risk.

Comparing the amount of lead with the US national standard shows that the concentration of lead is not at the appropriate level. The findings of this study can help in formulating appropriate strategies by city managers and prioritizing the control of heavy metals in the air.

Various models have been developed to predict methane generation and emissions from landfills. Due to their simplicity, the minimum number of required data, and the accuracy of the outputs, First-order decay are the most common models to predict methane generation in landfill,. Three important parameters in modeling landfill gas generation using a first-order model are the total weight of waste buried in the landfill, the methane generation potential, and the methane generation rate constant. The purpose of this research was to accurately estimate the parameters of the first-order model and to optimize it for estimating methane generation in the landfill and also to develop the ILGAM software.

ILGAM model consists of two submodels: 1) the gas generation sub-model and 2) the methane oxidation sub-model. The methane oxidation sub-model is based on the MOT model. The gas generation sub-model is based on a first-order equation with an emphasis on the contribution of the aerobic process in the estimation of the ultimate methane potential of waste. The parameters of the equation were modeled using the latest available results in the literature. To evaluate the model, the actual methane emission and methane oxidation were measured in the Karaj landfill. The results of the model, along with a few common models, were compared with actual data obtained from the Karaj landfill.

The ILGAM model predicted the gas emission from the Karaj landfill with an error of 5.8%. In contrast, LandGem, IPCC and CLEEN models predicted the methane gas emission from the Karaj landfill with an error of 74.4%, 40.2%, and 27.1%, respectively.

When compared to other models, the ILGAM model estimated the closest values to actual measurements for methane emission and methane oxidation in the Karaj landfill.  Owing to its user-friend Graphical User Interface (GUI), the model can be easily executed in a wide range of landfills by entering a few easy-to-measure data in the field.

Population growth and urbanization lead to mass production of waste. When municipal solid waste is landfilled, complex biological, chemical, and physical reactions occur that lead to greenhouse gas emissions. Methane is an important greenhouse gas, and the concentration of methane in the atmosphere is about 200 times lower than the concentration of di Is carbon monoxide, however, methane accounts for about 20% of heating. Emission of methane gas into the atmosphere will cause destructive environmental phenomena that reduce the stratospheric ozone of the ozone layer and over time increase the Earth's temperature. First, using the IPCC model, the amount of methane production in the Landfill of Halghe-Darreh in the study period from the beginning of 2015 to the end of 2019 is calculated and equal to 274.98 thousand tons of waste per year and the emission rate of methane gas in the landfill using the IPCC model. In the above time period is equal to 0.75 (g / sec). Then, the distribution of methane gas over a period of five years was investigated using the AERMOD model. The results showed that the distribution of methane gas with the AERMOD model for the whole landfill in the studied period in the northwest and southeast direction Around Landfill). Also, the maximum and minimum methane gas concentrations in the five-year period were 719.87 and 97.19 mg / cubic meter. Therefore, using two models, IPCC and AERMOD, the production and distribution of methane gas were calculated and the filling map up to 50 km of landfill was drawn.

In the last two decades, air pollution has become a serious problem, leading to a variety of harmful health effects. Street dust is a complex combination of pollutants from different sources, which can be a good indicator of air quality in the urban environment. So, this study was conducted to assess the health risk of toxic metals associated with street dust and identify their emission sources.

Dust samples were collected from three high-traffic districts in Karaj. After acid digestion, Cu, Zn, Cr, Mn, Ni, Ca, Ba, Sr, Li, Ti, Na, Mg, K, Fe, Al and V were measured using ICP-OES and Cd, Co, W and Pb were measured using ICP-MS.

The results of the measurement of elements in the street dust of Karaj indicated that compared to the amounts of elements in the earth's crust, the concentration (mg/kg) of Cd (X =0.9), Zn (X =479.15), Cu (X =159.37) and Pb (X =113.57) were at a very high level and the concentration (mg/kg) of Ni (X =69.36), Cr (X =93.96), Co (X =21.06), W (X =5.73) and Ca (X =75900) were at a relatively high level. In contrast, the concentrations of other elements (Ba, Mn, V, Sr, Ti, Li, Mg, Na, Ka, Fe, and Al) were in the range of values found in the earth's crust. Cluster analysis showed that Cd, Pb, Zn, Cu, Ni, Cr, Co, and Ca were mainly caused by anthropogenic activities, while other studied metals were associated with natural sources. Ingestion of dust particles was the main exposure pathway of toxic metals for both adults and children in Karaj. The Hazard Index (HI) in the children was higher than the adults, but it was lower than the safe level (HI≤1) in the both groups. Co, Cr and Cd had the highest carcinogenic risk among the studied metals.

The results of this study indicated that the street dust of Karaj is highly contaminated with toxic metals that long-term exposure with them can cause harmful effects, especially in children. Therefore, continuous monitoring of metal pollutants especially Co, Cr and Cd is recommended.

This study aimed to measure heavy metal concentration in the suspended particles which compare it in five different land uses in district 21 of Tehran.

The procedure was performed based on the ASTM D4096 and EPA standards. The sampling was performed using a high-volume pump for 20 minutes. The sampling was done every six days from five stations in district 21 in the spring of 2021. A total of 20 active samples of total airborne particles were collected from the residential, semi-residential, industrial, semi-industrial, and park stations. The airborne particle concentration was analyzed by the gravimetric method, and heavy metals were attached to particles using the ICP-OES. Descriptive tests of SPSS statistical software were used to analyze the data.

The results show that the lowest concentration of TSP is in the residential station with 42.34 µg/m3 and the highest concentration is in the industrial station with 253.30 µg/m3. In all applications except the park station, the aluminum has the highest concentration, and the lithium has the lowest concentration. The average concentration of the heavy metals in district 21 is an increasing trend of Al> Cr> Zn> Fe> Mg> Sr> Ti> W> Pb> Li, respectively.

The heavy metals in the airborne particles of district 21 have a high concentration and diversity. The factors affecting pollution in the study area include the resources, such as the industries, airports, and light vehicles.

The city of Tehran is always exposed to adverse consequences due to the establishment of various sources of heavy metals. Therefore, the purpose of this study is to identify the types of heavy metals in airborne particles and the origin of heavy metals in the 21st district of Tehran.

According to the EPA standard, 5 stations from District 21 of Tehran were selected for sampling. Using the ASTM D4096 method and using a high volume sampling pump, 50 samples of total airborne particles were collected. The samples were transferred to the laboratory and the concentration of heavy metals was measured by ICP-OES. The UNMIX source model was used to identify heavy metal sources.

The average concentration of heavy metals in 1400 is a decreasing trend including Li according to the concentration of heavy metals in the air in the SPECIATE database, the role of light vehicle sources was 47 percent 34 percent on the street and 18 percent at the airport.

The source of light vehicles exhibited the highest share of emissions and the element aluminum showed the highest concentration among heavy metals in Region 21. Therefore, the UNMIX source model can correctly identify index elements and priority sources for contaminant control.

Considering the importance of mobile sources in the release of air pollutants in the city, the need to develop and use public transportation is very important, for this purpose there are different approaches. Karaj city needs to replace the fleet with updated standards due to the outdated public transport fleet. Considering the economic and environmental dimensions, the effectiveness of the measures taken should be investigated. Therefore, evaluating the change in the release of pollutants based on each alternative scenario can help the authorities to adopt air pollution reduction strategies. The purpose of designing scenarios in this research is to estimate the effectiveness of scenarios in the field of replacing worn-out taxi fleets in reducing the emission of air pollutants. First, the classification of taxis based on parameters such as different systems, production year, emission standard, type of fuel consumed and vehicle class have been investigated. In the following, the scenarios of standard pollutant reduction were designed in two plans, the replacement of the worn-out fleet with a hybrid, dual-fuel fleet with consumable fuel, with the Euro 4 pollution standard, and finally, the scenarios were compared with the base scenario. The emission coefficients and design scenarios were calculated using the International Vehicle Emission Model (IVE) for roads, 1st grade arterials, highways and freeways, with slopes of zero and ±2%. The results of the comparison of the scenarios showed that by replacing the entire fleet worn out in terms of age (to a new fleet, the second scenario), the highest reduction in standard pollutant emissions was 68% (CO, 85% (VOC), 53% (NOX), 100% ( SOX) and 67% (PM). Also, the results of pollutant emission distribution in Karaj city, using Arc Map software, showed that the highest and lowest pollutant emissions are related to zone 10 and zone 1, respectively. Scenarios for reducing pollutant emissions And the solutions to increase air quality are useful and largely operational for politicians and researchers to better understand the current conditions of air pollution in the region, which require timely provision of funds and principled and detailed planning for implementation.

Today, due to the negative effects of oil mulches on the environment, has attracted a lot of attention the use of environmentally friendly mulches. The purpose of this study is to determine the best combination of vinasse, filter cake, bagasse and bagasse ash as mulch in terms of environmental indicators in the north of Khorramshahr. In this study, 81 treatments were provided with combination of vinasse (0, 100, 200 g), bagasse (0, 25, 50 g), ash bagasse (0, 25, 50 g), filtercake (0, 12.5, 25 g) and one-liter water. In the first step, among 81 treatments, were determined treatments in the appropriate range of salinity and acidity and in the second step, after mulching (35 optimal treatments in the first step) on laboratory trays (2×30×100 cm), have been measured shear strength, compressive strength, impact resistance, surface crack coefficient for optimal treatments with at least three replications. In the third step, the selected mulches are qualitatively scored. In the fourth step, the selected treatments in the previous step are examined in terms of the indicators of heavy elements (cadmium, chromium, lead, zinc, arsenic, mercury, vanadium, nickel), salinity, acidity and chemical properties (calcium, magnesium, sodium, sulfate, chlorine, phosphorus, (Potassium, organic carbon, nitrogen and sodium uptake ratio). In the last step, the treatments were ranked in terms of environmental indicators using the TOPSIS model and the treatment with the highest proximity index was selected as the optimal mulch. The results of TOPSIS model showed that treatment 19 (100 g vinasse, 50 g bagasse, no ash bagasse and 12.5 filter crack) with a proximity index of 0.89 was the first. Based on the results of this study, it can be concluded that the use of vinasse (100 g) in the optimal treatment will increase the rank of vinasse mulch in terms of environmental indicators with a proximity index of 0.89 and on the other hand, The presence of bagasse and filtercake in the optimal mulch has a significant effect on increasing the shear strength (up to 2 kg / cm2 compared to the control) and reducing the crack coefficient (up to 1.8% compared to the control).

Clean air is a necessity for human well-being and health. Air pollution is a major threat to humans and other organisms and is considered as one of the environmental challenges. Today, with the increase in air pollution, the need to know more about the causes of its occurrence has been raised. The various consequences of air pollution have made air quality monitoring and control inevitable in all societies at the forefront of environmental issues. In recent years, air pollutants have caused serious risks to human health and the environment. One of these pollutants Tropospheric ozone is the cause of health and environmental problems, especially respiratory problems and lung dysfunction and asthma attacks. Other effects of tropospheric ozone can be reduced lung capacity, cough, chest pain, sore throat, condition Nausea, damage to plants (growth disorders and the effect on germination) and reduced tire life, hence, it is necessary to know and study the tropospheric ozone in large and industrial cities. Tropospheric ozone is a pollutant because it plays an effective role in converting primary pollutants into secondary pollutants. Therefore, the aim of this study was to investigate the trend of changes in tropospheric ozone concentration with meteorological parameters, ozone precursors (nitrogen dioxide and nitrogen oxides). In this study, data from Kermanshah synoptic station and air quality station of Kermanshah General Department of Environmental Protection (Ziba Park station) in a long-term period of 10 years (2007-2016) have been used. Also, in this study using sensor images The OMI satellite Aura was surveyed in February and July 2016. Tropospheric ozone is known as a pollutant in Kermanshah. Therefore, no systematic studies have been conducted on the recognition of tropospheric ozone and the relationship between tropospheric ozone and meteorological parameters in Kermanshah over a long period of time. Tropospheric ozone and its relationship with changes in nitrogen oxides, nitrogen dioxide and synoptic parameters in Kermanshah were studied and the correlation between tropospheric ozone concentration and meteorological parameters was studied by Pearson test and the relationship between them was studied by linear regression. Based on the results. The maximum concentration of ozone occurs in the afternoon between 14:00 and 17:00 and the maximum amounts of nitrogen oxides occur at night and in the early morning of the year. Also, the study of seasonal changes in ozone concentration showed that in warm seasons due to the conditions of tropospheric ozone formation, including the intensity of sunlight, temperature and time of radiation and the presence of pollutants including nitrogen oxides, the concentration of tropospheric ozone was much higher. Ozone concentrations are highest in June, July, August, and spring and summer. The results also showed that there is a direct relationship between solar radiation and ozone concentration. Simultaneously with increasing solar radiation, it increases the air temperature, which increases the photochemical activity and thus increases the ozone concentration. This can be seen in the warm months of the year (June, July and August). Wind speed is also directly related to the concentration of tropospheric ozone. As the wind speed increases, the reactants mix faster and the tropospheric ozone concentration increases. However, precipitation is inversely related to the concentration of tropospheric ozone, which decreases with the occurrence of precipitation in the months associated with the onset of precipitation, and in the dry months of the year, the concentration is increasing. Therefore, meteorological factors and parameters play an important role in tropospheric ozone changes. Which can be seen by linear regression and Pearson test. The results of the study of nitrogen dioxide and nitrogen oxides showed that the highest concentration of nitrogen dioxide and nitrogen oxides during the day is the opposite of the concentration of tropospheric ozone and the lowest concentration of ozone occurs in summer due to increased solar radiation, increased oxidation of di Nitric oxide and nitrogen oxides, and as a result increase the concentration of tropospheric ozone, in autumn and winter, this amount has an increasing trend. Therefore, the trend of changes in tropospheric ozone concentration is the opposite of the concentration of nitrogen dioxide and nitrogen oxides, which can be seen in the daily, monthly and seasonal sections, which linear regression and Pearson test show this important and OMI sensor images confirm this fact. In conclusion of this study, all parameters related to the concentration of pollutants along with meteorological parameters have been effective factors in the concentration of tropospheric ozone.